January | February 2012 - International Aquafeed

Volume 15 I s sue 1 2 012

the international magazine for the aquaculture feed industry

The effects of dissolved oxygen on fish growth in aquaculture

On-farm feed management practices– for three Indian major carp species in Andhra Pradesh, India

Oxygenation in aquaculture

Developing a plant-based diet- for Cobia Rachycentron canadum

Volume 15 / Issue 1 / January-February 2012 / © Copyright Perendale Publishers Ltd 2012 / All rights reserved

WHO CARES...

DOES!

Alltech European Bioscience Centre | SarneySummerhill Road | Dunboyne | Co. Meath | IrelandTel: +353 1 825 2244 | Fax: +353 1 825 2245 | alltech.com facebook.com/AlltechNaturally @Alltech

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An internAtionAl mAgAzine for the AquAculture feed industryCONTENTS

aquaI n t e r n a t I o n a l

feed

Volume 15 / Issue 1 / January-February 2012 / © Copyright Perendale Publishers Ltd 2012 / All rights reserved

Aqua News

4 AquativisgrowinginVietnam5 CargillacquiresHigashimaruVietnamCoshrimpfeedmillinVietnam6 Newfilmshowsfirstlinkinafullyresponsibleaquaculturesupplychain6 DrMinTheinreceivesSeniorLifeTimeAchievementAwardinMicroAlgal

BioTechnologyatthe5thInternationalAlgaeCongressinBerlin8 WynveenmovestonewpremisesinHeteren9 PascalDivanachrecognisedbyhighestEASAward

Features

10 Theeffectsofdissolvedoxygenonfishgrowthinaquaculture

14 On-farmfeedmanagementpracticesforthreeIndianmajorcarpspeciesinAndhraPradesh,India

18 Bulkstorage&handling

26 Flakedfishfeedsversuspelletedfishfeedforthefishhobbist

28 Redefiningmineralrequirements:-Whyisitnecessary?

30 Oxygenationinaquaculture

34 Developingaplant-baseddietforCobiaRachycentroncanadum

40 Useofsoybeanproductsinaquafeeds:Areview

Regular items

24 PHOTOSHOOT42 CLASSIFIEDADVERTS43 BOOKREVIEW

MakingFisheriesManagementWork MethodsinReproductiveAquaculture

44 INDUSTRYEVENTS46 THEAQUACULTURIST48 WEBLINKS

International Aquafeed is published six times a year by Perendale Publishers Ltd of the United Kingdom.All data is published in good faith, based on information received, and while every care is taken to prevent inaccuracies, the publishers accept no liability for any errors or omissions or for the consequences of action taken on the basis of information published. ©Copyright 2012 Perendale Publishers Ltd. All rights reserved. No part of this publication may be reproduced in any form or by any means without prior permission of the copyright owner. Printed by Perendale Publishers Ltd. ISSN: 1464-0058 www.perendale.co.uk

Welcometothestartof2012andit’sgoingtobeaneventfulyearindeed.WeinGreat Britain are hosting the Olympic Games and Her Majesty the Queen’sDiamondJubileewillbemuchinthenews.TheUSAwillbeelectingtheirPresidentandlet'shopeabetterfinancial

yearisinstorewhatevertheoutcomes.

In February/March Aquaculture America 2012 will be held in Las Vegas with plenty of representa-tion from the feed industry and a list of interesting speakers. I will be there so I’m hoping to meet many of our subscribers and IAF will have a stand so please make every effort to visit us if you can.

Later in August we see the ISNF Fish Nutrition & Feeding Symposium in Molde, Norway, with a heavy focus on the research and development contributions from the leading scientists across the globe in the many disciplines of aquatic animal nutrition.

Topics will include sustainable resources of ingredi-ents, health, welfare and ethics, new methods and working-tools, feed technology and feeding regimes, nutrigenomics and molecular nutrition. ‘omics’ data and system biology models as well as nutritoxicology and whole life cycles nutritional require-ments. May sees the annual Alltech symposium in Lexington, Kentucky with a special session on aqua-culture nutrition.

In October, BioMarine Business Forum comes to London to be held at the prestigious Fishmongers’ Hall, which will turn our attention to emerging marine biotechnology and applications for the aquafeed industry with ‘think tank’ sessions to cover contemporary topics and especially the feed additive area. The last meeting in Nantes in September 2011 reported in the previous IAF was highly successful.

Aquaculture depends on quality feed, but the life support systems allowing maximisation and efficiency of production throughout the different life stages are critical too for metabolism of nutrients and to release energy from feed.

Oxygen is the key to life and certainly fundamental to the demands of fish and crustacean species but also to the aerobic micro-organisms inhabiting bio-filtration systems such as those encountered in recirculation technology. The effects of dissolved oxygen on fish growth in aquaculture are of para-mount importance and so I am pleased to see two articles in our first issue of 2012 concerning oxy-genation in aquaculture and relevance to aquafeed.

We have features from several experts in their knowledge of oxygen requirements for fish with atten-tion to fish physiology, environmental considerations and the relationship with feeding and diet com-position. Pavlos Makridis, Nils Hovden Yovita John Mallya, Kingolwira National Fish Farming Centre, Fisheries Division, Ministry of Natural Resources and Tourism Tanzania present a valuable perspective of balancing oxygen demands of fish with metabolism.

Pavlos Makridis, Nils Hovden and Martin Gausen (Stovic) describe the technical basis of oxygen meas-urements in water from a chemical perspective and ion/ electrode interactions.

Aaron Watson and colleagues discuss current trials to use selected plant ingredients as protein sources for cobia. Aaron is undertaking his Doctoral research programme at the Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and I am very grateful for his input, sharing his findings to a wider audience. Daniel Leeming is also a young PhD worker at Plymouth and reviews the role of zinc in fish nutrition as part of our trace element features.

Pablo Tepoot Founder of New Life Spectrum (fish food forum) and edited by Martin Little presents details of flaked food for ornamental fish and discusses the merits of controlled feeding regimes to safeguard tropical fish from problems associated with excessive feeding and nutrient digestibility.

Alf Croston Managing director of Croston Engineering Bulk Storage and Handling provides us with information on feed storage issues, translocation and the technology of bins and silos within the milling sector.

On farm feed management practices for three Indian major carp species rohu (Labeo rohita), catla (Catla catla) and mrigal (Cirrhinus mrigala) in Andhra Pradesh, India by R Ramakrishna adds to our regular Feed Management section, which has been expertly overseen by my colleague Krishen Rana for the last two years.

Together with our news and advertising pages and of course the regular Martin Little blog, we have an excellent line-up to initiate the New Year and offer informative reading, enjoy!

EditorProfessorSimonDaviesEmail:[email protected]

Associate EditorProfessorKrishenRanaEmail:[email protected]

Editorial ManagerMartinLittleBSc(Hons)Email:[email protected]

Editorial Advisory Panel• Abdel-Fattah M. El-Sayed (Egypt)• Professor António Gouveia (Portugal)• Professor Charles Bai (Korea)• Colin Mair (UK)• Dr Daniel Merrifield (UK)• Dr Dominique Bureau (Canada)• Dr Elizabeth Sweetman (Greece)• Dr Kim Jauncey (UK)• Eric De Muylder (Belgium)

• Dr Pedro Encarnação (Singapore)

Subscription & CirculationTutiTanEmail:[email protected]

Design & Page LayoutJamesTaylorEmail:[email protected]

International Marketing Team

CarolineWearnEmail:[email protected]

SabbyMajorEmail:[email protected]

LeeBastinEmail:[email protected]

Latin American Office

IvànMarquettiEmail:[email protected]

More information: InternationalAquafeed7StGeorge'sTerrace,StJames'SquareCheltenham,GL503PTUnitedKingdom

Tel:+441242267706Website:www.aquafeed.co.uk

Professor Simon Davies

Croeso (welcome in Welsh)

24 -25 October - Fishmonger’s Hall - London – UK

Marine Bio-Resources(ingredients, aquaculture, aquafeed, cosmetics, nutraceuticals

cleantech, biotech, and pharmaceuticals)

• Unique venue• 8 Think-tank sessions and 2 reporting sessions

• 12 Company Presentations

• 2 Networking lunches

• A Networking dinner

• Closing gala dinner• Opening key note session

• Closing key note session

• One-to-one meetings

A world of Business opportunities to explore:Seats are limited: Only 250 attendees (Executives and CEOs)


Marine Bio-Resources(ingredients, aquaculture, aquafeed, cosmetics, nutraceuticals

cleantech, biotech, and pharmaceuticals)

• Unique venue• 8 Think-tank sessions and 2 reporting sessions

• 12 Company Presentations

• 2 Networking lunches

• A Networking dinner

• Closing gala dinner• Closing gala dinner• Opening key note session

• Closing key note session

• One-to-one meetings

A world of Business opportunities to explore:Seats are limited: Only 250 attendees (Executives and CEOs)

Book now at: www.BioMarine.org

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Aquativ, par t of Diana Group and specialist of Functional Hydrolysates

for the aqua feed industr y, opened a representative office in Ho Chi Minh City in November 2011.

Nguyen Anh Ngoc, chief rep-resentative of the new develop-ment, is proud of this important step. Mr Ngoc has been part of the pioneer team since the begin-ning of the Aquativ adventure in 2007.

“I’m very happy that we are now opening this office in Ho Chi Minh. I spent a significant time in our research center based in

France to learn the fundamental of our product and a few years between Vietnam, France and Thailand to start and develop our sales network in the country.

“The opening of our produc-tion facility in Thailand with our partner TC Union Agrotech in 2010 helped us to offer a very good range of functional hydro-lysates for the fish and shrimp feed industry. As we planned, sales have been taken off very well in Vietnam where we supply both shrimp feed and fish feed manufacturers,” he said.

Aquativ offers two product r anges in the V ietnamese

aquafeed market. On is the Nutr ipal© range of qual ity mar ine raw mater ials (Tuna soluble extract, Tuna crude oil, Tuna liver powder) essen-tially used for its high nutr i-tional value in the formulations (protein, omega 3, DHA).

The Actipal© range, its new gen-eration of Functional Hydrolysates designed to improve the feed performance and ultimately the farming productivity.

Performance is due to the high concentration of low molec-ular weights compounds such as peptides, free amino acids and nucleotides generated by the hydrolysis bioprocess.

“This new office in addition with our factory in Thailand demon-strates our commitment to serve even more our Vietnamese cus-tomers and is aligned with our company tagline ‘the closer-the-better’. We are proud the

industry has been rewarding us beyond the product perform-ance by considering our capability to deliver consistent, reliable and fully traceable products.

“This result has been achieved thanks to our industrial standards such as GMP, HACCP as well as our strict supply chain control. This industry is driven by the high standards imposed by the overseas markets like EU and US and our product full traceability has been a major asset for our customers exporting to these markets.

“That makes us unique and very confident on the development of our sales in the South East Asia region,” says Vincent Percier, General Manager of Aquativ Thailand.

More inforMation

Nguyen Anh Ngoc Chief Representative Email:[email protected]:www.aquativ-diana.com

Aquativ is growing ......inVietnam

4 | InternatIonal AquAFeed | January-February 2012 January-February 2012 | InternatIonal AquAFeed | 5

Aqua News

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Ho Chi M inh C i t y, Vietnam, November 14, 2011. Cargill Vietnam

announced today that it has completed the asset purchase of a shrimp feed mill located south of Ho Chi Minh City from Higashimaru Vietnam Co LTD. The sale will give Cargill full ownership of the mill and will be Cargill’s first investment in Vietnam’s shrimp feed industry.

Constructed in 2008, the mill is strategically located close to some of the largest commer-cial shrimp farms in Vietnam. The shrimp mill acquisition will add to Cargill’s existing feed portfolio, which includes swine, poultry and fish feed. Cargill expects to begin producing Cargill shrimp feed for commercialisation within two to three months after making addi-tional investments to the mill.

“Shrimp farming is a growing

industry, and this mill is a good complement to our existing feed business in Vietnam. It allows Cargill to quickly enter the shrimp feed manufacturing market in Vietnam with significant capacity and to begin to service shrimp producers,” said Pedro A Curry, Cargill’s General Manager for Aquaculture in Vietnam. “We look forward to expanding our business and to working with Vietnamese shrimp producers and helping them succeed.”

Added Hoàng Thông Thái, Cargill’s National Sales Manager for Shrimp, “We are excited to be bringing our best technology to Vietnamese shrimp producers. Shrimp growers will be able to rely on Cargill to supply them with high-quality, top formulated and best-of-class manufactured nutritional solutions and technical services.”

Cargill is one of the leading animal nutrition companies in Vietnam. The company began with its first feed mill in 1997 and today operates six feed mills throughout the country. Serving the swine, poultry, fish and shrimp feed markets through a network of about 1,200 dealers in addition to direct sales; Cargill applies the newest animal nutrition technology to its feed.

About CargillCargill is an international producer

and marketer of food, agricultural, financial and industrial products and services. Founded in 1865, the privately held company employs 138,000 people in 63 countries. Cargill helps customers succeed through collaboration and innova-tion, and is committed to applying its global knowledge and experi-ence to help meet economic, envi-ronmental and social challenges

wherever it does business. For more information, visit www.cargill.com and its news center.

About Cargill in VietnamA whol ly owned subs id-

iary of Cargill, Cargill Vietnam Limited established a presence in Vietnam when the United States and Vietnam normal-ized relations in 1995. Today the company operates six animal feed mills, purchases and exports cocoa bean and imports ferrous, food ingredients and feed mate-rials. Cargill is a good corporate citizen of Vietnam and has built 48 schools throughout the country, mainly in remote rural areas to help economically disadvantaged children, and also provided over 1,000 scholarships. The company also supports centers for disabled children and helps victims of natural disasters.

Cargill acquires HigashimaruVietnamCo. shrimp feedmill in Vietnam


Aqua News

http://www.cargill.com/

http://www.cargill.com/

http://www.cargill.com/news/index.jsp

A new film on the inde-pendent cer tification program for fishmeal

and fish oil instigated by the Internat iona l F i shmeal and Fish Oil Organisation (IFFO) s hows how i t i s r ap i d l y becoming the recogn i sed s t andard fo r mar ine feed materials.

Leading supermar ket and seafood brands, international fish farmers and NGOs say why they believe the program i s the f i r s t l ink in a fu l ly responsible aquaculture value chain.

The eight-minute film was premiered at the IFFO Annual Conference in Lima, Peru. Delegates also heard that, just two years after its launch, nearly 30 percent of the wor ld’s fishmeal and fish oil production capacity was now certified to the RS Standard.

Steve Bracken of salmon pro-ducers Marine Har vest says of the cer tification program: “Having a Standard like that says a lot about the integrity of our feed supplies”.

Peter Hajipieris of Birds Eye Iglo

adds: “It is critically important to us to demonstrate to consumers that what they eat is safe and that we are not plundering the planet”.

Ally Dingwall of Sainsbury’s explains that his company’s responsibil ity to consumers must extend right back along the supply chain to ensuring that the wild fisheries that supply fishmeal and oil are responsibly managed.

The film features an animated diagram showing all the stages in the aquaculture value chain to the feed. Dawn Purchase of the Marine Conser vation Society explains that aqua-culture must develop in the most environmentally sustain-able way possible and that its future depends crucially on the responsible production of fishmeal and fish oil.

New film shows first link in a fully responsible aquaculture supply chain

Dr Andrew Jackson, Technical Director of IFFO, who led the development of the IFFO RS and features in the film.

Dr. Min Thein, General Manager (retd) from the Myanmar Spirulina

Factory, Sagaing and Professor Botany, Mandalay University in Myanmar, has received the Senior Life Time Achievement Award 2011 in Microalgal Biotechnology during the 5th International Algae Congress in Berlin December 6, 2011. He received this award because of his scientific and industrial innovations and the worldwide promotion of micro-algae.

Microalgae - the small versa-tile aquatic plants we are all fas-cinated with - were responsible

for pulling together more than 125 participants from around the world in the beautiful Radisson BLU Hotel in the German city of Berlin earlier this week.

Microalgae was the keyword under discussion. The organisers; the European Society of Microalgal Biotechnology, the German DLG e V and DLG BENELUX in the

Netherlands look back to a very successful event.

The international character of the 5th IAC was underlined by the fact that par-ticipantsthis time came from over 30 coun-

tries, +94 percent compared with the 4th IAC in

Amsterdam last year, and rep-resented not only European nations but also amongstothers companies and institutions from Suriname, Azerbaijan, Singapore, Japan, USA, Australia, India, La Reunion and Mongolia.

Dr Min Thein receives Senior Life Time Achievement Award in MicroAlgal BioTechnology at the 5th International Algae Congress in Berlin

LINK

6 | InternatIonal AquAFeed | January-February 2012

Aqua News

January-February 2012 | InternatIonal AquAFeed | 7


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Wynveen International BV moved into its new premises in

Heteren, The Netherlands, on December 1, 2011. This building, a brand-new production space with offices at the Poort van Midden Gelderland business park, replaces the premises at the business centre that had been home to

Wynveen for the past few years. The official opening took place on December 16, 2011.

Wynveen International bv is a leading edge Dutch company specialising in the design, produc-tion and erection of complete plant and installations for the animal feed industry and the key equipment and systems used in them. Wynveen plant and installa-tions can be found in many coun-tries.

Wynveen International BV is an innovative company that has been producing machinery and equip-

ment for livestock feed, aqua feed and petfood production for many decades. Quality, reliability and inno-vation are the pillars on which the organisation is built. The numerous examples of innovations intro-duced by Wynveen include the CryLoc rotary sifter, the special extraction bottom, the hammer mills with two grinding chambers

or adjustable brake plates, the unique vacuum coating system and the wide variety of mixers.

Wynveen was previously located in a business centre. Willem de Vaan says, “Increasing turnover and a growing workforce meant that we had to expand our office and pro-duction space. We also had an urgent need to carve out our own niche and develop a face of our own.”

The new premises were designed entirely with the aim of making Wynveen’s production process as efficient as possible. It is spacious and offers plenty of room to receive guests.

A solar installation generating just under 60,000Wp has been installed on the roof of the new building. The solar power system takes up a roof area of more than 1000m2. At a cautious estimate, the system should feed at least 52,000kWh electricity back into the grid. With an advanced data mon-itoring system, information such as electricity yield, energy savings and CO2# savings can be viewed anywhere in the world.

More inforMation:W de Vaan, Director Wynveen International BV Tel:+31264790699Fax:+31264790698Email:[email protected]

Inge Fokkes, Marketing ManagerTel:+31795932221Fax:+31795931147Email:[email protected]

WynveenmovestonewpremisesinHeteren“With thecompletionof thisnewbuilding,Wynveen InternationalBVnowhasafaceofitsownandanimagethatwecanbeproudof.”


Aqua News


At the final wrap up and closing session of the Aquaculture Europe ,

2011 event organised by the European Aquaculture Society (EAS) in Rhodes, Greece, Dr. Pascal Divanach, Director of

the Institute of Aquaculture and member of the Board of Directors of the Hellenic Center for Marine Research (HCMR), was presented with an Honorary Life Membership of EAS.

The Honorary Life Membership is the highest EAS award and is given to those persons that have had a marked impact on the development of European aqua-culture. Since 1981, EAS has bestowed this award on only 9

persons, including G. Ravagnan (Italy, since 1981), Dr. E. Monten (Sweden, since 1987 †), Dr. Bernard Chevassus-au-Louis (France, since 1989), Dr. Eric Edwards (UK, since 1991), Peter

Hjul (UK, since 1993 †), Prof. Trygve Gjedrem (Norway, since 1995), Mr. J. Bally (Mar tinique, since 1997), Dr. Colin Nash (USA, since 2000) and Mr. Cour tney Hough (Belgium, since 2010).

The EAS 2010-2012 President Y ve s H a r a c h e , w h o expressed his own personal pleasure in the nomination that had been approved by the EAS Board of Directors during AE2011, and fittingly presented to Dr. Divanach on his ‘home soil’, presented the award. His HCMR col-l e ague and a s soc i a te researcher at the Institute of Aquaculture, Dr. Nikos Papandroulakis, introduced the awardee...

“When the EAS president asked me to speak about this person, I thought it was easy until I actually started thinking what to say. Then I realized how difficult is to speak about a person that has done many things and actually marked Greek and I would dare to say European aquaculture.

This person has been working in the academia for his entire career but was/

is always speaking about com-mercial production. When he produced the first million juvenile sea bass, he used wild plankton and since then many millions have been produced.

The migration of this person through the Mediter ranean region can be associated with the “movement” of the aqua-culture production from West to East. A characteristic of this per son is his dedication to understand the logic behind the biology and the technology that led him to develop rearing methods that match per-fectly the physiological needs of the fish as for example the mesocosm larval rearing tech-nique and self-feeders.

Most probably you have already understood to whom I am refer-ring. Ladies and Gentlemen, it is my great honour and pleasure to present you the Director of the Institute of Aquaculture of the Hellenic Center for Mar ine Research, Dr Pascal Divanach”.

Yves Harache added his own personal appreciation of Pascal’s work and the way in which is set the standard to larval rearing of Mediterranean species. He there-fore found it fitting to present “Pascal the tenth” with a signed copy of a previous HLM award, Dr. Colin Nash’s book “The History of Aquaculture”. He added that a more formal commemora-tive plaque is being prepared for Pascal. Judging from the appre-ciation showed by the audience, Pascal Divanach was a deserving and popular awardee.

PascalDivanachrecognised by highest EAS Award

New EAS Honorary Life Member Pascal Divanach (left), being congratulated by EAS 2010-2012 President Yves Harache, with a signed copy of “The History of Aquaculture”.


Aqua News

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Commercial aquaculture isgrowing worldwide except inAfrica where production is stilllow. With fisheries reaching a

stagnating phase, the world and more soAfrica will have to look to aquaculture inthefuturetoprovidefishproductsthatwilllikelybeneeded.Inviewofthis,astudyonwaterqualitymanagementwasdonewhichspecificallylookedattheeffectsofdissolvedoxygensaturationonfishgrowth.Thestudywas done through a review of literatureand a case study usingAtlantic halibut. Inthecasestudy,halibutof20-50ginweightwere reared in replicate at 60percent, 80percent,100percent,120percentand140percent oxygen saturation levels in a tankrecirculationsystem.

The effect of oxygen saturation levels on growth and feed conversion ratios were taken after two weeks. The results showed that oxygen saturation level had a positive effect on the growth and feed conversion ratio when it was set at 80 percent to 120 percent saturation. At 140 percent the growth was slightly lower and the feed

conversion ratio was higher at 60 percent and 140 percent compared to the other groups. The conclusion was that oxygen saturation level has an effect on growth and feed conversion ratios of fish, and in the case of Atlantic halibut, the growth rate is higher when the oxygen level is between 80 percent and 120 percent. The feed conversion ratio for halibut was lower at 120 percent oxygen saturation.

Gas exchange and oxygen concentration in water

Oxygen as a gas has a low solubility in water. In addition, the amount of oxygen contained in water varies with temperature and

salinity in a predictable manner. Less oxygen can be held in fully air-sat-urated warm seawater than fully air-saturated cold freshwater. While the oxygen content of the water sets the absolute availability of oxygen in the water, it is the oxygen partial pressure gradient that determines how rapidly oxygen can move from the water into the fish’s blood to support its metabolic rate.

This is because oxygen moves by diffusion across the gills of fish. According to Fick’s law of diffusion, the gill area determines the rate of diffusion of oxygen across the gills, the diffusion distance across the gill epithelia, the diffusion constant and the difference in partial pressure of oxy-gen across the gills (Crampton et al. 2003).

Consequently, partial pressure of oxygen is the most appropriate term for expressing oxygen levels in aquaculture water.

However, oxygen concentration is the more commonly used term and, for a

given temperature and salinity, the par tial pressure of oxygen and oxygen content in water are linearly related. Another suit-able method for expressing oxygen levels in aquaculture is percent air saturation (often reduced to just percent satura-

The effects of dissolved oxygen on fish growth in aquacultureby Yovita John Mallya, Kingolwira National Fish Farming Centre Fisheries Division, Ministry of Natural Resources and Tourism, Tanzania

"The effect of oxygen saturation levels

on growth and feed conversion ratios

were taken after two weeks. The results

showed that oxygen saturation level

had a positive effect on the growth

and feed conversion ratio when it

was set at 80% to 120% saturation"


FEATURE


Figure 1

Figure 2: Diagram showing the structure for respiration (gas exchange) in fish. (Source: Microsoft Encarta.1993-2002. www.kwic.com 2008-02-08)

tion), which is directly propor tional to the par tial pressure and is repor ted on most oxygen probes that have built in algorithms for temperature and salin-ity (Bergheim et al. 2006). In this study percent saturation was used.

Oxygen uptake in and carbon dioxide release from the fish

During respiration fish, like other animals, take in oxygen and give out carbon dioxide. The process is done by using gills in almost all fish although some can also use the skin and some have lung like structures used in addition to gills. When a fish respires, a pres-surised gulp of water flows from the mouth into a gill chamber on each side of the head. Gills themselves, located in gill clefts within the gill chambers, consist of fleshy, sheet like filaments transected by extensions called lamellae. As water flows across the gills, the oxygen within them diffuses into blood cir-culating through vessels in the filaments and lamellae. Simultaneously, carbon dioxide in the fish’s bloodstream diffuses into the water and is carried out of the body (see Figure 1).

Function of fish gillsFor most fish species gills work by a

unidirectional flow of water over the epithelial surface of the gill, where the transfer of gases occurs (O2 in, CO2 out). The reason for this unidirectional flow of water is the energetic nature of the system. The energy that would be required to move water into and out of a respiratory organ would be much more than that used to move air because water holds low oxygen due to its low solubility (Groot et al. 1995). The blood flowing just under the epithelial gill tissue usually moves in a counter current flow to that of the water moving over it.

This allows for most of the O2 to be taken in by the blood because the diffusion gradient is kept high by the blood picking up

oxygen as it moves along, but always coming into contact with water that has a higher O2 content. The blood receiv-ing the O2 continues to pick up O2 as it moves along because fresh water is being washed over the epithelial lining of the gills (Jobling 1995). By doing so, the fish ventilate the gills while also taking in oxygen and releasing carbon dioxide (Groot et al. 1995).

However there are two ways fish ventilate their gills: buccal/opercula pumping (active ventilation) and ram ventilation (passive ventilation). In buccal/opercula ventilation the fish pull in water through the mouth (buccal chamber) and push it over the gills and out of the opercula chamber (where the gills are housed). At this time the pressure in the buccal chamber is kept higher than the pres-sure in the opercula chamber so as to allow the fresh water to be constantly flushed over the gills.

In ram ventilation, a fish swims with its mouth open, allowing water to wash over the gills. This method of ventilation is common to fast moving fish, and it enables tuna to keep enough oxygen going to the gill surface while swimming at high speed (Boyd and Tucker 1998). During this time the oxygen is absorbed into the blood while carbon dioxide diffuses out of the blood to the water.

Effect of oxygen on fish growth

Oxygen is impor tant in respiration and metabolism processes in any animal. In fish, the metabolic rate is highly affected by the concentration of oxygen in the rearing environment. As the dissolved oxygen concentra-tion decreases, respiration and feeding activities also decrease. As a result, the


FEATURE

growth rate is reduced and the possibility of a disease attack is increased. However, fish is not able to assimilate the food consumed when DO is low (Tom 1998). Overall health and physiological conditions are best if the dissolved oxygen is kept closer to saturation. When the levels are lower than those mentioned above, the growth of the fish can be highly affected by an increase in stress, tissue hypoxia, and a decrease in swimming activities and reduction in immunity to diseases.

However, there is a need to maintain the level of dissolved oxygen at the

saturation level which will not affect its physiological or metabolic activities, so as to have high production in any culture system (Wedemeyer 1996). More than that, one has to keep in mind that the oxygen level requirement depends on the species, but also on fish size and activ-ity of the fish. According to Tom (1998) oxygen require-ments per unit weight of fish significantly decline with increasing individual weight.

In carp this reduction may be expressed by the following ratios: yearling = 1, two-year-old carp = 0.5–0.7, marketable carp = 0.3–0.4. Significant dif-ferences in oxygen demand are also found for different species. Using a coefficient of 1 to express the oxygen requirement of common carp, the comparative values for some other species are as follows: trout 2.83, peled 2.20, pike perch 1.76, roach 1.51, sturgeon 1.50, perch 1.46, bream 1.41, pike 1.10, eel 0.83, and tench 0.83.

Growth There was no significant difference in

growth rate of the Atlantic halibut reared at different oxygen saturation levels (Figure 3) during the first period (SGR1). However, there was a significant difference (p<0.02) in the growth rate of the fish during the second period (SGR2). Then the SGR of fish reared at 100 percent saturation was significantly higher than that of fish reared at either 60 percent or 140 percent saturation.

The results of the experiment under different oxygen levels clearly showed that the level of oxygen saturation affects growth. During the second period the SGR was highest at 100 percent saturation. The best FCR was obtained in the groups with the highest growth rate although there was no significant difference in FCR of fish reared at different oxygen saturation levels. The growth of other species of fish is also affected by oxygen saturation such as tilapia (Tsadik and Kutty 1987) and Atlantic salmon (Crampton et al. 2003, Seymour et al. 1992, Forsberg and Bergheim 1996). The growth of Atlantic halibut and Atlantic salmon increases with increasing saturation up to 100 percent saturation. However, these species appear to be more sensitive to oxygen saturation than tilapia ■


FEATURE

Figure 3: The graph showing the specific growth rate (SGR) of Atlantic halibut reared at different oxygen saturation levels

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by R Ramakrishna Senior Scientist, Fisheries Research Station, SV Veterinary University Undi, Andhra Pradesh, India

Global aquaculture productionis estimated at 66.7 milliontonnes. Asian fed aquaculturecontributed for 54 percent of

the total aquaculture production.The esti-matedfishproductionfromAsiacontributed88.5percentoffishintermsofquantityand71percentintermsofvaluetototalworldfedaquacultureproduction(FAO,2006).

Global food fish production projected by the year 2020 is 130 million tonnes, out of which the production from aquaculture is expected to be 53.6 million tonnes. The estimated production form carps, barbs and other cyprinids from India was 10.74 million tonnes (Brugere and Ridler, 2004).

India is a carp country from aquaculture point of view. There has been a phenomenal expansion of commercial carp culture in con-structed earthen ponds in certain Indian states such as Andhra Pradesh, Punjab, and Haryana.

In several other states (Orissa, Karnataka and Tamilnadu) commercial carp culture is gaining momentum. Reservoirs and other freshwater bodies are also the important sources of Indian major carp production in India.

The recent freshwater fish production in India is 3.7 million tonnes of which about 80 percent (2.96 million tonnes) is from the production of the three Indian major carps namely Labeo rohita Hamilton (rohu), Catlacatla Hamilton (catla), and Cirrhinus mrigalaHamilton (mrigal) from Asia. There produc-tion is: rohu, 1,332,000; catla, 1,331,000 and mrigal, 360,000 tonnes (2008a). About 90 percent of the production of the three Indian major carps is expected to be contributed from India.

Widely cultivatedIndian major carps are widely cultured in

Bangladesh, Myanmar, Nepal and Pakistan also. Both rohu and catla were introduced in to nine non-native countries and mrigal in to seven such countries (Welcome, 1988).

Until the 19th Century carp culture was confined to backyard ponds in Eastern Indian states west Bengal, Orissa and Bihar. The source of seed for this type culture was natural seed from reverine resources. The advent of successful induced breeding through hypophysation in 1957, carp seed production technology provided an impetus for a new era of carp culture in the country.

The demonstration of successful com-posite culture of Indian- and Chinese major carps by the Central Inland Fisheries Research Institute in West Bengal state during the peri-od 1963 through 1984 (Jhingran, 1991), and massive demonstration of this culture tech-nology through Fish Farmers Development Agencies located through out the country inspired private farmers to take up seed pro-duction and pond culture of major carps on a commercial scale.

In Andhra Pradesh, pond culture of Indian major carps was initiated in the Kolleru Lake region in 1976, with the construction of 133 fish ponds by the State Government, covering an area of 2040ha.

Success achieved by a few private farmers during the initial years of culture encouraged people belonging to a cross section of the society in Krishna and West Godavari districts to take up commercial fish culture in and around Kolleru Lake on a large scale.

Other factors, which contributed to the rapid development of fish culture in this region, include, frequent inundation of agricul-tural cropland due to floods, increased cost of labour, and low return from paddy crops.

By the year 1981 several fish farms ranging from 2 to 100ha were constructed in this region (Gopal Rao, 1987). Fish culture area

continued to expand beyond 1981 result-ing in the conversion of about 5000ha of flood-prone fallow land and even agricultural fields. Most of the carp culture area in Andhra Pradesh is located in and around the Kolleru Lake (Nandeesha and Gopal Rao, 1989).

By 1985, fish culture expanded on a large scale to other irrigated areas in Krishna and Godavari districts and on a smaller scale to Nellore, Guntur, Prakasam and East Godavari districts. shows the estimated culture area of Indian major carps in the Kolleru and surround-ing areas in the West Godavari and Krishna districts during 1981 to 2010.

The culture area of Indian major carps reached a peak of 80,000ha. With the gradual expansion of pangus culture, 10,000ha, of area originally belonged to the culture of Indian major carps has been converted for mono or mixed culture of Pangasianodon hypoph-thalmus, Sauvage, (pangus), introduced in to Andhra Pradesh in 1994 to 1995 from Bangladesh via West Bengal State, India.

Thus, the culture area of Indian major carps reduced to the presently estimated 70,000ha. Presently the total pangus area in the state is estimated to be 20,000ha. The field observations indicate that the culture area of both Indian major carps and pangus is still expanding in West Godavari, Krishna, East Godavari and Nellore districts.

The Kolleru Lake and surrounding areas in the West Godavari and Krishna districts is the present cradle of Indian major carps and pangus culture. In East Godavari and Nellore districts estimated the culture area is 4000ha each.

Capture fisheriesTraditionally, Kolleru Lake has been a rich

wild fisheries resource. Capture fisheries pro-duction was 7000 tonnes in 1974. During the years of normal environmental conditions the

On-farm feed management practices for three Indian major carp species

in Andhra Pradesh, India


FEATURE


production contributed by fish other than carps was about 50 percent, and prawns and carps was 30 percent and 10 percent respectively (Venkateswara Rao et al., 2003).

Source water for fish culture In West Godavari, Krishna and East

Godavari districts the fish farmers are allowed to draw water only from the agricultural drains, for which they pay Rs. 500/- as a revenue charge. In Nellore district water for fish culture is drawn from irrigation canals, drains. In this district sub soil water (drawn out mechanically for bore wells) is also a major sources for fish culture. The ponds or farms of a fish farmer are registered by the state government on the insistence that the farmer uses only drain water for the culture.

Organic manures and inorganic fertilizers

Manures and fertilizers play a key role in the Indian major carp culture in producing phytoplankton and zooplankton. The two most widely used organic manures poultry manure followed by cattle manure are abun-dantly available in the state and in the fish culture areas also since Andhra Pradesh is basically an agrarian state, with rich population of cattle, and stands number one in the coun-try in poultry farming. The poultry manure is a waste at poultry farms and is to be disposed off. Poultry manure is supplied to farmers through dealers, who maintain contacts with the owners of big poultry farms located across the state.

The mode of transport is by 10 to17 tonnes capacity lorries. The transport cost, which comes to Rs250 to 300 per tonne (Rs100=US$1.89) is included in the price paid by the farmer. The dealer gets a commission of Rs200 to 300 per 10 tonnes of poultry manure delivered. Cattle dung is usually procured from the production points in the near by

areas not by dealers, but by the trac-tor owners in the local

areas. They deal with the owners

of the production points and transport the manure up to a distance of five to 20km; each tractor can transport two to three tonnes of cattle dung. Besides the transport charge, the owners obtain a commis-sion of Rs75 to 100 (Rs100=US$1.89) per each tonne cat-tle dung delivered.

Among the chemical fertilisers, single super phos-phate, di-ammonium phosphate and urea is the widely used fertilisers, through potash and complex fertilisers are also used. These fertilis-ers are commonly used in the rice agri-culture and other crops grown in the same districts.

Both the groups of farmers, of agri-culture and fish cul-ture, purchase the chemical fertilisers from the state gov-ernment - author-ized local dealers, or local agricultural cooperatives stores.

All these are under the control and regulation of the district Agricultural


FEATURE

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Officers. During the periods of shortage, the agricultural officers ensure that the chemical fertilisers are sold to agriculture farmers only. Fish farmers have to wait till the free avail-ability of the fertilisers restores or they have to purchase them through rice agriculturists usually at a little higher price.

Electricity Fish farmers are allowed to use electricity

for fish culture management. The electricity is usually supplied for seven hours, but often intermittently due to shortage of power supply. Farmers represent that they need a continuous supply of electricity or at least uninterrupted power supply during 9pm to 8am, during which period the dissolved oxygen in the ponds often fall to critical levels and hence aeration of ponds with the help of engines becomes a necessary and often the most crucial remedial measure to save the crop.

Sources of finance The main sources of finance for fish farm-

ers in the state are the nationalised banks and the district co-operative central banks with their branches in the fish culture areas, and private financiers.

Nationalised banks The nationalised banks have an almost

uniform policy of granting loans to fish farmers in the state. The banks sanction an amount of Rs100,000 (Rs100=US$1.89) for construction and Rs400,000/ha for crop loan at 18 percent annual interest rate of against mortogation of the documents of the land of the farmer. The loan sanctioned for pond construction is called tern loan, and this loan may be repaid with in three to seven years, as opted by the farmer. The crop loan is to be paid after harvest of each crop.

A farmer is eligible to obtain crop loan for his next crop, even with in one year, if he repays

the current crop loan. If a lessee has a valid agreement signed by the owner of a pond or farm, for a period of five consecutive years, the lesser is also eligible to obtain crop loans from the nationalized and local co-operative banks.

Co-operative banks At the present the co-operative banks are

granting a working capital to meet the cost of culture for one year or less than on year culture period (not for pond digging or other costs of construction). The scale of finance for each ha water spread area is Rs275,000 to 300,000 (Rs100=US$1.89) for the culture of Indian major carps and Rs550,000 for pangus culture.

Private financiers In the interior Kolleru Lake the villages

from in to co-operative societies, not by reg-istration, but by mutual understanding. Each of these co-operative bodies, locally called ‘Bantas’ comprise 40 to 50 members and col-lectively culture ponds of 15 to 20ha.

The executive committee of the ‘Banta’ used to obtain loan required for one-year culture period from the private financers at 36 percent annual interest rate. Private financers usually don’t insist for any collateral security, the loans are given mainly based on the repay-ment capacity and personal creditability of the farmer. All the members share the net profit equally.

One variation of Banta management in the recent years is that the member’s lease out their ponds to a group of four to five villagers, who raise the capital required for culture and the lease amount, is shared by the members.

Of all the Indian major carp culture areas in Andhra Pradesh the lease amount is the highest in these Banta villages. As the Indian major carp culture established in the Kolleru area a rich class of farmers developed in these villages and presently, the Banta farmers bor-row money from these farmers at an annual

interest rate of 18 percent instead of from the private financiers elsewhere at higher rate of interest.

National Fisheries Development Board

The National Fisheries Development Board (NFDB) was established in July 2006, in Hyderabad, Andhra Pradesh. NFDB is an autonomous organization under the administrative control of the Department of Animal Husbandry, Dairying and Fisheries, of (the Government of India). The overall objective of the board is to empower all Indian states and union territories through implementing various activities related to almost all spheres of fisheries and aqua-culture in the country and also through providing financial support mainly through subsidies.

NFDB provides financial assistance to the eligible candidates for the establishment of feed mills of large scale (installed capacity five tonnes/ha), medium scale (two tonnes/ha), and small scale (1.2 tonnes/ha) units. For the first two categories a loan up to 40 percent of the cost of machinery equipment and building is sanctioned at an annual inter-est rate of five percent.

For the small scale unit a subsidy of 20 percent of the total unit cost (which is Rs750,000 (Rs100=US$1.89) in this case with a limit of Rs15,000 per unit) will be provided.

For freshwater fish culture NFDB sanc-tions Rs300,000/ha for construction of a new fishpond for culturing existing species or new species, (for example pangus), with 20 percent subsidy, but with a ceiling of Rs60,000/ha. For special category of farmers belonging to scheduled castes and schedule tribes the subsidy is 25 percent, with a ceil-ing of Rs75,000 / ha.

For cost of inputs, including feed, NFDB sanctions Rs50,000/ha (with 20 percent sub-sidy) for one crop period for Indian major carps, and all other existing species, (for example Chinese major carps which have been cultured in the state for many years).

For pangus culture, the input cost pro-vided is Rs500,000/ha with 40 percent subsidy for an initial period of two years and there after 20 percent for all farmers, and 25 percent for the special category farmers mentioned. NFDB also provides financial assistance for renovation of aged aquaculture ponds, fish seed farms, estab-lishment of fish hatcheries, prawn and shrimp hatcheries.

Besides, NFDB provide grants to the government fishery institutes, and the other eligible agencies for conducting training programs, demonstrations for the benefit of aquaculturists. ■


FEATURE


As with most things in life, thebasics remain thesamealthoughtheymaybecomemoresophisti-cated,orcomplicated,dependent

onone’sviewpoint.

And so it is with this overview covering the bulk storage and handling of materials in the animal feed and human food industries, from the intake of raw materials through to the discharge of finished products.

It is barely 60 years since a very high proportion of the milling industry was located at the major ports with raw materials in sacks being transported from the docks by horse and cart and then hoisted up to the various floor levels for storage there to be cut and tipped into process bins as and when required.

Gradually, as more home grown grain became available, together with the advent of purpose-built bulk vehicles and an improved road network, there was a move to country mills more conveniently located to service the farming community by buying grain locally, processing it into feed and selling the resultant product back to the farmer.

The use of computers and automation throughout the milling process has reduced what was a labour intensive industry to one controlled by a few technically proficient operators, but to whom the basics of mate-

rial handling must still apply, as do health and safety requirements, adherence to DSEAR/ATEX Explosion Regulations, plus health and hygiene control.

Hence this résumé.

Interruptions in productionThe interconnection of process plant is

designed to be fail-safe and so prevent chokes and interruption to production.

Intake capacity from bulk tankers has greatly increased over the years and is nor-mally well in excess of 100 tonnes/hour via an intake hopper with safety grid located under cover plus an efficient dust extraction system, and discharging into a screw or chain type conveyor which may, if wished, be fitted with a variable speed drive so that the intake rate may be varied to suit the characteristics of the particular material being dealt with in order to prevent overloading subsequent equipment.

The conveyor should be fitted with rota-tion control and overfeed detection.

The intake bucket elevator, as with all similar units in the mill, must incorporate explosion relief panels at prescribed intervals, electrically linked to shut down the plant in the event of an explosion occurring.

Because of their inherent design, bucket elevators have a built-in explosion risk factor and, if located within a building, the explo-sion panels should be ducted to atmosphere.

Elevators should also incorporate tensioning gear at the boot, anti-runback device to cater for a choke or power failure, rotation sensor to indicate if the belt is slipping and side align-ment indication.

Intake points are frequently out of sight of the control room so, to avoid being allowed to run empty for long periods, and a proce-dure should be in place to shut down when not in use.

A rotary drum pre-cleaner located at the top of the Mill to remove foreign matter prior to the material being conveyed to raw mate-rial bins will protect subsequent equipment from being damaged.

The conveyors feeding silos and bins will have multiple outlets and the electrical control system must be designed so that only one slide is open at a time in order to prevent the propagation of an explosion from one bin to another. As with the intake conveyor, all con-veyors should incorporate overfeed detection and rotation sensing.

To cater for dust laden air displacement at transfer points, small dust units with built-in exhaust fans at convenient locations will ensure a clean atmosphere.

Storing different materialsThe number, location and holding capacity

of new material bins is determined by site conditions and the particular requirements

Bulk storage & handlingby Alf Croston, Managing Director, Croston Engineering, UK


FEATURE


of individual clients, bearing in mind the large number of different materials to be handled and stored in the feed industry. Ranging from free flowing grains to a variety of meals and moisture content, the bins and discharge equipment should be designed to cater for those with the worst flow characteristics to ensure maximum flexibility so that individual bins can be used for the storage of any ingre-dients should the need arise.

Level probes are required to prevent over-filling, as are policed explosion panels.

Provision will be required for minerals and other ingredients that are delivered by bulk tanker and pneumatically conveyed to dedi-cated bins utilising either a blower mounted on the tanker chassis or, in some cases, by coupling up from a land-based blower. To prevent static electricity causing a spark, the tanker will be connected to an earthing point prior to starting the discharge process. Care is needed to ensure that the tanker only couples up to the correct intake line feeding the des-ignated bin and that intake lines are of correct diameter, earthed and routed with minimum horizontal length and number of bends in order to reduce the pressure needed to carry out the conveying operation.

As referred to earlier, the configuration of hopper design and type of discharge is all-

important in ensuring the free flow of materi-als from the bins to the blending operation. For accuracy this will include one or more main weigh hoppers, a small weigh hopper for minerals, and a smaller one for micro ingredients.

The blended batch is fed to the grinding plant preceded by a screen to allow meals and minerals to bypass the grinder before re-joining the ground materials and passing to

a three tier mix-ing assembly consisting of pre-mix bin, mixer and dump bin. Molasses and fats are added at the mixer.

Although heat treatment is outside this remit covering bulk handling it is a matter that requires attention whether it is for conditioning of mashes for direct sales or for pelleting. The three essentials being moisture, temperature and time, whilst bearing in mind


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LSL

MCC 2

LSL

MM

LS

DP

LS

MCC 1

66

LS

M

LS

LS

LS

4

5

10

6

DP

the heat sensitivity of some ingredients. For pelleting, correct conditioning is necessary to ensure starch gelatinisation and pellet quality.

An efficient cooling system is essential prior to finished products being conveyed to packing or bulk out loading bins, the latter discharging either directly to bulk vehicle or via a travelling weigher.

Most of the materials processed in the animal feed, pet and fish food, grain, flour, bakery, sugar, starch and fertiliser industries are subject to the DSEAR/ATEX Explosion Regulations that came into operation on July 1, 2003. There are many misconceptions and confusion as to the requirements of the Directives. It is timely to reiterate the general principles relating to the regulations, particu-larly for those who have only recently become involved in one or other of the industries in which potentially explosive materials are handled.

The DirectivesThe Directives apply from July 1, 2003,

to all new equipment and any existing that is modified or relocated after this date. This has particular relevance in ensuring that, if purchasing any second-hand equipment, it complies or can be economically altered to comply.

Good housekeeping, regular inspection and maintenance, plus an awareness of poten-tially hazardous processes or areas, are a requisite for trouble free operation. The Directives combine these aspirations into requirements and apply not only to the sup-pliers of equipment but, in particular, to the users themselves.

Dust classificationIt is the obligation of the user to sat-

isfy himself as to the class or classes of the materials to be handled and to provide this

information to the designer or manufacturer of equipment.

These are defined under four Kst classifica-tions (K staube = Class of dust), and relate to rate of pressure rise.

Kst. 0 = Non-explosiveKst. 1 = Weak to moderateKst. 2 = StrongKst. 3 = Very strong

Most materials used in feed mills are cov-ered under Kst. 1 but there are a few to which Kst. 2 could apply.

ZoningIn addition to dust classification, the user

is required to carry out a survey and to designate plant and buildings into zones which will be appropriately signed at points of entry. Zones 20, 21 and 22 are the most likely to apply to feed milling and associated industries.

Zone 20 covers an area in which an explosive atmosphere consisting of combus-tible dust in air is present frequently for long periods or continuously.

Zone 21 is where an explosive atmos-phere is likely to occur occasionally in normal operation.

Zone 22 is where an explosive atmos-phere would not normally occur but, if it does, it would only be for a short period.

Obviously it is the duty of management to ensure that standards of operation and cleanli-ness are maintained to meet the requirements of Zone 22 as far as is practical.

In carrying out risk assessments it is natural to concentrate on major processing equip-ment such as silos, grinders, elevators, dust collectors, etc., and to overlook the myriad range of smaller ancillary items that also need to be checked. Typical items include lighting, electrical fittings, motors, level indicators, sole-noid valves, control panels. In fact, anything that can generate a spark.

It is well known that three elements are required to cause an explosion – dust in suspension at a critical level, oxygen, and a spark or hot surface. The first two are always there, so it is against the third item that every precaution must be taken, including satisfac-tory earthing throughout the plant.

Bear in mind that dust in suspension appearing as a light fog provides the condi-tion in which a spark can cause an explosion. The finer the dust particles the greater the danger because of the increased surface area exposed to atmosphere.

The duties of the user having been described in general terms, what about the supplier of the equipment? Firstly, he has to satisfy himself that the user has provided him with all the necessary details concerning clas-sifications of materials to be processed and


FEATURE



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the areas in which equipment is to be located, together with any other relevant information.

The supplier then has to ensure that the equipment he supplies is designed, manufac-tured and installed to satisfy requirements by taking all precautions to prevent an explosion but also, and most importantly, to mitigate against an explosion should such an event occur.

Equipment can be manufactured in such heavy construction that an explosion would be contained but this is so expensive as to be impractical. The alternative is to fit a certi-fied explosion panel vented to atmosphere through a nearby wall or roof.

Due to the location of plant within a build-ing venting may not be practical and so the fitting of expensive flame quenching or explo-sion suppression equipment may be required.

To prevent the propagation of an explo-sion, items of equipment should be isolated from each other. An example being to incor-porate valves or slides so that only one bin can be filled and exhausted at a time. Bin dischargers and screw conveyors can be designed with chokes incorporated.

The installation of a rubble separator on the intake system and magnets at appropri-ate points throughout the plant are obvious precautions.

Very often a primary explosion in itself is not dangerous but the vibration it sets up dis-turbs any dust lying on floors, beams, rafters, into the atmosphere. If a source of ignition is present it can result in a secondary and dev-astating explosion. So, cleanliness throughout the plant is of first priority with particular attention being paid to “out of sight” areas and cleaning up spillages immediately – using one of a variety of vacuum cleaning systems available. Brushing up is definitely out – it only disperses the dust elsewhere.

Despite taking all precautions that one can

think of, it is sod’s law that incidents still take place – thankfully not too often in view of increased awareness of the dangers that are always present.

ExamplesThree examples illustrate the variety of

incidents that can happen. The first resulted from smouldering mate-

rial entering a bin, setting off a primary explosion which ruptured the explosion panel as it was designed to do. Unfortunately the escaping gases caused a secondary explosion which devastated the top floor of the build-ing. As it was impractical to vent every bin to atmosphere it was subsequently agreed

with HSE that the top floor over the bins would in future be a “no go” area whilst the plant was in pro-duction and for ten minutes afterwards. A lockable gate was fit-ted to the access stairs and a warning notice affixed.

The second result-ed from a hot spot due to a malfunction in the motor of a dust unit fit-ted on top of a grinder expansion hopper. The explosion panel rup-tured but had not been vented to atmosphere through a nearby wall.

Unfortunately, two employees were stand-ing nearby at the time and were badly burned. It was interesting to note that a choke had been fitted to the bin discharger beneath the expansion hopper and prevented the explo-sive gases passing into a subsequent elevator and storage bins, otherwise the result would have been even more serious.

The third was caused by welding being carried out on the side of a silo, one of several such accidents over the years, in which the operator was injured. In this case it was not the result of negligence. The silo had been isolated from its feeding conveyor, cleaned down internally and the subject of a work per-mit. Unfortunately, a small amount of material had remained in an inaccessible spot and on being disturbed created the conditions for an explosion to take place.

The foregoing describes in broad outline the rationale behind the ATEX Directives. Many of the requirements are common sense, but com-mon sense has to be backed up with documentation in this day and age. However, the following may be found

helpful as an “aide memoire” towards good housekeeping;• Enforce a strict no-smoking rule, on pain

of dismissal.• Ensure that all electrical equipment,

cabling and control panels conform to relevant standards and regulations, and are kept free of dust.

• Use only totally enclosed, fan-cooled motors, ensuring they are adequately earthed.

• Ensure light fittings are dust-proof.• Test cables and wiring regularly.• Locate switchgear and process control

panels in dust-free rooms under light negative pressure.

• Inspect liquid lines regularly for leaks. Ensure that insulation, if used, has not become impregnated, as this could be ignited by electrical trace heating.

• Bund walls around main storage tanks should be sized to suit.

• Check that bearings, particularly those fitted to elevators and grinders, are not over-heating.

• Detect belt slip and misalignment on elevators – a major source of fires – by rotation and side alignment sensing, and anti-run-back protection.

• Check for possible temperature rise in stored bulk materials, which could result in spontaneous combustion.

• Inspect bin interiors using only battery-operated, non-glass, flameproof inspec-tion lamps, which are suitably secured and never allowed to be in contact with the product. (In the past it was not unusual for naked electric bulbs to be lowered into bins – at best protected with a wire guard).

• Ensure hot work is carried out only on isolated, cleaned-out plant, against Work Permit issued by management, and pro-vision of fire blankets, extinguishers, etc.

Many fires have occurred during periods of repair, renovation or plant modification (as in the case of Windsor Castle a few years ago). During these special periods, in addition to taking fire precautions, it is advisable to inspect the area closely for at least an hour at the end of each working day.

Adherence to these principles will ensure not only a pleasant environment in which to work but also one that is as intrinsically safe as possible. ■

About the author:Mr Alf Croston is managing director of Croston

Engineering, at Tarvin, near Chester, which was founded in 1976. His company specialises in the design and building of bulk storage, handling and process plants throughout the UK and Ireland for many household names in industry.


FEATURE

"Many fires have occurred during periods

of repair, renovation or plant modification

(as in the case of Windsor Castle a few

years ago). During these special periods,

in addition to taking fire precautions, it is

advisable to inspect the area closely for at

least an hour at the end of each working day"


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Any discussion that involves fish food deserves a brief explanation on these two types of com-mercially prepared foods.

While flakes have been the most popular type of food for the past 50 plus years for hobbyists, commercial operations learned a long time ago that pellets are the superior choice for all feeding applications.

Pellets are preferred over flakes due to the fact that they are more nutrient dense, and much more stable in water. For species of fish over two-three inches, pellets are clearly the most optimum method of providing nutrition to your fish. Not only can you feed much less on a volume basis, but pellets will also remain stable in the aquarium for an extended period of time.

By their very design, flake foods are paper-thin; absorb water very quickly, and

while doing so leach out much of the water-soluble vitamins in a very short period.

Some studies suggest that once flakes are added to the aquarium, the majority of water-soluble vitamins (such as vitamin C) are leached out of a flake food within 60-90 seconds. This information has been common knowledge in the aquaculture circles for several decades, yet some hobbyists seem to be stuck using outdated and less than ideal methods for feeding their aquarium raised fish.

Using pellet food for all feed applications is yet another concept that has been proven in commercial aquaculture since its inception.

Learning to feed fishFeeding fish might seem easy, but it is actu-

ally one of the most difficult things to teach.

In my 35 years of being in the commercial fish business, I have rarely run across an employee who knows how to feed fish properly.

It is necessary to have the sense of aware-ness not to overfeed or underfeed. In some ways it is as much an art, as it is a science.

The first rule of thumb is; when in doubt, underfeed! If necessary you can always rec-tify the situation later by increasing the feed amount.

However, if you overfeed, then eventu-ally you can run into some serious prob-lems. While most hobbyists usually overfeed their fish; there are also those that underfeed their fish to such an extent that their fish actu-ally look anorexic.

Many reef keepers are guilty of this due to phosphate and nitrate concern. If the fish is truly fat, simply withhold food and feed less. If the fish is too thin, simply feed more.

A hobbyist should know that they are in control, not the fish. A healthy fish will always beg for food, but if the fish shows no interest in food, chances are you have a big problem. Either they are sick, or in very bad water conditions. When you feed pellets, the correct size is very important.

Large fish can eat small pel-lets, but if the pellet size is too large for the fish, they will usually spit it back out, or expel a large portion of the pellet into the water column while chewing.

Different sizes of pelletsThe key is to use a pellet size that allows

the fish to swallow it whole. If you keep a mixture of fish sizes in the same aquarium, you can mix different sizes of pellets to ensure that all of the fishes receive their fair share.

Another common mistake by some hob-byists is to pre-soak their pellets, in the

misguided belief that this will aid in digestion and prevent swelling of the pellets inside the fishes gut. This is nothing more than an urban myth created by those that simply do not understand the amount of enzymes and gas-tric acids that are released by most fish when they consume food.

Those hard pellets turn into soft mush in a very short period of time! If a pellet food causes gastrointestinal issues in a fish, it will usually be due to the use of poorly digestible ingredients, such as excessive amounts of grains and grain by-products, not from the food swelling up inside the fish’s stomach. Most importantly, when you pre-soak pellet food, you are allowing nutrients and water soluble vitamins and minerals to leach out into

the water. Palatability: Fish are governed

by olfactory senses and to cer-tain extent taste buds. Needless to say, unless the fish is attracted to the food, no matter how nutritionally superior it may be, it will be useless. Food as ener-gy intake has to surpass energy output i.e. locomotion, meta-bolic function, etc, especially in marine fish. Even though they may be eating in an aquarium, they can and often will waste away slowly until they cease to exist.

A nutrient packed food will produce substantial growth rate and optimum health. The type of protein used has to be easily digested and absorbed by herbivores, omnivores and carnivores. As stated earlier, fish do not receive an abundant food source in our miniscule aquarium environments. Whatever food you feed, it must provide ample daily nutritional requirements for the fish to thrive. Superior food generally produces less waste, hence less pollution in your aquarium.

A high quality fish food should be able to bring out the wide spectrum of natural colors

Flaked fish feeds versus pelleted fish feed for the fish hobbyistby Pablo Tepoot, founder of New Life Spectrum (Fish Food Forum), Florida, USA and sub-edited by Martin Little, IAF

"Superior food generally

produces less waste, hence less

pollution in your aquarium"


FEATURE


in a fish, not just the color red. It should not turn a Yellow Tang or Yellow Labidochromis, orange, which is often caused by excessive use of astaxanthin. Fat content should ideally be below 10 percent to avoid fatty liver disease, except in the case of juvenile fish, which require fat as an immediate energy source in order to spare the much-needed protein for building muscle.

Maintaining healthChoose a food that can maintain long-term

health for years, not months. I have personally maintained numerous Angelfish, Surgeonfish, Butterfly Fish, etc. for over 10 years, and they

show no sign of aging! How long do fish live if their nutritional needs are met? I suspect that in many cases it should be 20 plus years.

I also suspect that very few hobbyists have kept the aforementioned species of fish alive for such long periods of time. For some peo-ple one or two years would be considered a success story! We are not talking about Damsels, Clown fish, Triggerfish, or other spe-cies that are rather easy to keep in captivity, but the marine species that are considered ultra delicate by most hobbyists.

Superior food generally produces less waste, hence less pollution in your aquarium. In other words, excess undigested protein,

fiber, minerals (ash), will expel through the gills and feces creating phosphate, ammonia, and nitrogen compounds.

This is the reason why Kelp, Spirulina, grain and other difficult to digest proteins should keep at a reasonable percentage. Many hob-byists seem to think that they have to add more Kelp, vegetable matter or Spirulina into their fish’s diet, unknowingly adding more pol-lution to their aquarium. Fish simply cannot utilize all the additional mineral (ash) and fiber.

A quality food usually contains ample amount of vegetable matter and minerals. Always remember, what goes in has to eventually come out. ■


FEATURE

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The increasing development ofaquafeed technologies embraces anew generation of feed ingredientsand additives leading to changes in

thespecificationofdietformulations.

This necessitates a new understanding of mineral nutrition and the need to redefine trace element requirements in keeping with intensive production whilst promotion of fish health.

This short review gives a basic outline of the biological mechanisms involved in one of these trace elements, zinc and describes why it’s important to re-evaluate the mineral require-ments for salmonids.

Why is zinc important? ‘Micro-nutrients’ is a generic term for die-

tary components required in small quantities. Minerals such as copper, zinc, iron, manganese and selenium are all micronutrients although they are usually categorised as trace minerals, and are essential for the health of all animals, including fish.

In aquaculture these dietary essentials are often supplemented as part of a vitamin/mineral premix due to the inadequate supply obtained from many commercially used feed ingredients.

Zinc is the most abundant trace mineral found in fish. It is essential for growth, the development and maintenance of healthy bones, and over 300 proteins require zinc as either a structural of functional co-factor. These include approximately 20 metalloenzymes such as alkaline phosphatase (required for bone min-eralisation/formation), alcohol dehydrogenase (required for fructose metabolism) and carbonic anhydrase (required to aid the removal of CO2 from cell respiration).

Fish deficient of zinc shows growth retardation, cataracts, fin and skin erosion, increased mortality rates and taste dysfunc-tion resulting in reduced appetite and feed conversion.

How does the fish obtain zinc?Fish have two routes of zinc uptake, first from

the diet and second from the surrounding water. There is the potential for waterborne zinc to be absorbed in both the gut, from the swallowed external water, and also directly from the exter-nal aqueous environment via the gills.

Salmonids “drink” very little, especially when in freshwater; freshwater zinc levels are usu-ally less than 10µg/l and saltwater levels even lower. This is considered too low to make any significant contribution to the whole body zinc levels even though the gills affinity for zinc is extremely high.

However, even with this high affinity the uptake rate of zinc from the gill is three to four times lower than from the gut (Bury et al, 2003). The uptake mechanism in fish is described as high affinity low capacity in the gills and low affinity but high capacity in the gut.

This supports the theory that despite the high affinity for zinc in the gill, dietary uptake is the major contributor to the body zinc status.

Free zinc ions (i.e. not bound to other com-pounds) are potentially very toxic to many bio-logical processes, yet the incorporation of these free zinc ions in numerous proteins is vital for these very same biological processes to function.

Thankfully, from a toxicological stance, only a very small fraction of the total zinc in the environment is in this “free” state.

Unfortunately, from a nutritional stance, the majority of zinc in the environment is therefore unavailable. For the zinc to become available these compounds need processing in some way.

This processing occurs when the compound is digested, freeing the potentially toxic zinc ion, which can now cross the intestinal barrier; or breaking the large compounds down into their smaller components, which can cross the intestine and take the zinc with it. Once inside the organism any free zinc is usually bound to another compound generally termed a chap-erone, ready to be used or transferred around the body.

How and where is zinc used?Zinc is very highly regulated in all aspects of

the fish’s body: its uptake from the water or the diet; its excretion by the gills, the intestine, the urine or the integument; and also by its distribu-tion within the body.

This regulation means that even a dietary level of 1700mg/kg ZnSO4 is still non-toxic to the fish. The ability to regulate this appears to come from the intestine, it is thought that excess zinc is simply not absorbed and passes through the fish in its faeces, however, it hasn’t been proved that the high levels of zinc remaining in the faeces hasn’t been processed by the liver and excreted back into the faeces in the bile.

Either way, excess zinc in the diet does not seem to present a problem. Low dietary zinc levels are however more serious and the regula-tory mechanism more complex.

Every tissue of the fish can be broadly grouped into one of two categories; either functional or exchangeable. A functional zinc pool, such as the liver, fins, eyes, gills and skin are generally considered metabolically important. It is these tissues, which maintain their zinc concentration regardless of the dietary levels. Exchangeable pools seem to be less important metabolically but it is in these tissues (bone, muscle, intestine) we see fluctuations in zinc levels corresponding to the dietary levels.

When the dietary supply exceeds require-ment these tissues increase in zinc concentration and act as a storage facility and when the diet is deficient it is these pools that decrease quickly and allow the metabolically important tissues to maintain their zinc levels. Regardless of the ability of the fish to regulate zinc within its body the turnover of zinc is relatively fast (~1% per day). This means that in order to avoid deficiency a continual supply of dietary zinc is essential (Davies et al., 2010)

Dietary zinc requirementsResearch into mineral requirements, espe-

cially trace minerals such as zinc is well defined

Redefining mineral requirements:

by Dan Leeming PhD Research Student, Aquaculture and Fish Nutrition Research Group, University of Plymouth, Uk

Why is it necessary?


FEATURE


for many higher organisms, but for fish only the commercially valuable species have received sig-nificant attention. Numerous studies have been carried out on rainbow trout, Atlantic salmon and Channel catfish; these species have well defined and frequently cited requirement levels.

These requirement levels tend to be cal-culated using purified (non-realistic) diets and inorganic forms of the minerals. In reality, aqua-culture diets contain anti-nutritional factors (ANFs); these are components of the feed that inhibit the uptake or utilization of another part of the feed. When concerned with mineral digest-ibility and availability two of the main ANFs are tricalcium phosphate and phytate (phytic acid). Tricalcium phosphate is found in the bone tissue of animals and phytate in many plant proteins.

These ANF’s bind to minerals such as zinc and effectively render them unavailable to the fish. An example of the effect of these ANFs can be seen in rainbow trout. Rainbow trout have a requirement of 15-30mg Zn/kg diet (Ogino and Yang, 1987). This was calculated using a purified egg albumin diet, with no ANFs, and using an inorganic zinc sulphate. When a practical diet containing fishmeal was used an additional 40mg Zn/kg diet (probably bringing the total dietary zinc level closer to 80-100mg Zn/kg diet) was required to maintain normal growth.

Similarly, Atlantic salmon fed a fishmeal diet containing 65mg Zn/kg could not maintain their normal zinc status (Lorentzen and Maage, 1999).

The higher the bone content of the fishmeal the more zinc needs to be added, espe-cially when using an inorganic zinc salt. The replacement of fishmeal with plant protein may exacerbate this effect. Rainbow trout fed a soyabean meal based diet required 150mg Zn/kg to achieve optimal growth. The increased use of sustainable fishmeals, often from trim-mings high in bone content, and plant protein sources high in phytate may mean that a set of minimum requirement levels for fish fed more realistic diets will be of more practical use to the industry.

The development of more advanced feed supplements such as proteinate sources of min-erals may reduce the effect of ANFs on mineral availability. Mineral proteinates bind the mineral within their structure, ‘protecting’ the mineral from the ANFs.

This relationship between the protein and the mineral is complex. The mineral has to be bound tight enough not to be released in the gut where it would be a free mineral ion, susceptible to the ANFs, just like an inorganic salt, but the mineral still needs to be available to the animal once it has been taken into the cells.

If the correct protein/mineral complex is used the level of the mineral used in the diet can be reduced by as much as 70 percent (Paripatananont and Lovell, 1995; channel catfish with zinc methionine).

If research into the type of protein/mineral

complex is carried out for each species the effi-ciency of mineral supplementation can be hugely improved. It would also reduce the problems (lower availability and excessive mineral excretion) associated with higher levels of mineral inclusion, which is required when using more sustainable animal and plant based protein sources. ■

References:

Bury, NR, Walker, PA, Glover, CN, 2003. Nutritive metal uptake in teleost fish. J Exp Biol. 206, 11-23.

Davies, SJ, Rider, S, Lundebye, A-K, 2010. Selenium and zinc nutrition of farmed fish: new perspective in feed formulation to optimise health and production. In: Bury, NR, and Handy, RD (Eds) surface chemistry, bioavalability and metal homeostasis aquatic organisms: An integrated approach. SEB, London, pp. 159-181.

Lorentzen, M, Maage, A, 1999. Trace element status of juvenile Atlantic salmon Salmo salar L fed a fish-meal based diet with or without supplementation of zinc, iron, manganese and copper from first feeding. Aquac. Nutr. 5, 163-171.

Ogino, C, Yang, G.Y, 1978. Mineral requirements in fish.4. Requirement of rainbow-trout for dietary zinc. Bulletin of the Japanese Society of Scientific Fisheries. 44, 1015-1018.

Paripatananont, T, Lovell, RT, 1995. Responses of Channel Catfish Fed Organic and Inorganic Sources of Zinc to Edwardsiella ictaluri Challenge. Journal of Aquatic Animal Health. 7, 147-154.-


FEATURE

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D ry air consists of approxi-mately 21 percent oxygen,78 percent nitrogen andonepercent argon. In addition to

these gases there is also carbon dioxideat a concentrationof0.04percent,whichdespite its low level is physiologicallyimportantforalllivingorganisms.

In comparison with air, oxygen content in water bodies, which are in equilibrium with the atmosphere, is considerably lower.

There is a variability of solubility of atmospheric gases in water. Oxygen is about twice as soluble as nitrogen, but carbon dioxide is in its turn 30 times more soluble than oxygen. The concentration of oxygen in water and air is 0.007 liter/liter and 0.209 liter/liter, respectively. This means that the oxygen content in water is approximately 30 times lower than oxygen in an equal volume of air.

Besides oxygen concentration, two more factors are physiologically important in rela-tion to physical constraints of gases and ultimately the way land-living animals and aquatic animals have evolved to obtain oxygen in their respective environments: density of medium and diffusion. Air is the medium for land-living animals and it is about 800 times lighter than water. In addi-tion oxygen diffuses much faster from air to living tissues in comparison with oxygen dissolved in water.

Analysis of all these factors makes it clear that respiration is a much easier task for land-living animals than for aquatic animals. The only disadvantage of air-breathing animals in relation to breathing is the loss of water during breathing, which is not an issue of course in the case of aquatic animals.

Oxygen content in the water is influenced by temperature, salinity

Temperature has a major impact in relation to oxygenation of fish or other animals: on one hand the metabolic rate of the animals increases (as long as the increase in temperature is within the tolerance limits of the cultured animal), and on the other hand the solubility of oxygen in water gets lower. In other words, at higher temperature, the demand for oxygen gets higher, while the oxygen available decreases.

Another factor that reduces the solubility of oxygen in water in addition to increased temperature is the presence of dissolved salts. The presence of salt ions reduces the ability of gases to dissolve in water. Oxygen is therefore less soluble in seawater compared with freshwater. As shown in Table 1, temperature has a much stronger effect on oxygen solubil-ity than salinity, as at high tem-perature solubility decreases by more than 30 percent, whereas at high salinity solubility decreases

by 16-18 percent. We noted before that solubility of gases is influenced by the solids dissolved in it.

It is important to underline here, that the solubility of each gas is not influenced by the other gases dissolved in the water within physiological limits. This means that for exam-ple the solubility of oxygen is not directly influenced by the amount of carbon dioxide dissolved in it.

Respiration in fishIn fish, gills are the respiratory organs. The

gills are highly perforated with thin blood capillaries, which get loaded with as much oxygen as possible from the water. The gills are enclosed in the gill cavity. The anatomical arrangement of the gills is such that blood flows in the gill lamellae in the opposite direc-tion than the flow water. The counter-current principle is therefore applied which results in

the pattern of flow of the blood, such that blood just before it leaves the gill lamellae is in contact with highly oxygenated water (see figure), and it is possible to increase further its oxygen content.

There are two basic mechanisms to achieve a flow of water over the gill surface. The first mecha-nism is the respiratory pump composed by the mouth cavity and the opercular cavity. The mode of action of the respiratory pump in fish is not continuous, but takes place in pulses composed of two phases. The respiratory pump consists of two compartments: the mouth cavity (buccal cavity) and the gill cavity (opercular cavity).

The gills separate these two compartments. So water passing from mouth to gill cavity has to pass through the gills.

Oxygen requirements are influenced by species cultured, temperature, fish size and feeding regime. Fish, like other animals, consume food and break it down to more simple compounds. The dual purpose of metabolism is thus the gain of energy (catabolism) and the build-up of tissues (anabolism) by polymerisation of more simple compounds, which becomes visible in the form of growth.

The anabolic processes besides building stones require as well energy. Production of energy takes place through oxidation and requires in the case of fish the presence of oxygen which is extracted from the water surrounding the fish, and acquired through the gills as described earlier. If a substrate

Oxygenation in aquacultureby Pavlos Makridis, Nils Hovden and Martin Gausen, Storvic Ltd, Scotland, Uk

Figure 1. Schematic diagram showing the blood flow in secondary gill lamellae which are the actual site of gas exchange in fish. Water flows in the opposite direction than blood optimizing the extraction of oxygen from water to the blood in this counter current pattern of flow.

table 1: Solubility coefficient of oxygen in water expressed as ml per liter per mm Hg as a function of salinity (ppt) and temperature at extreme temperature and salinity to demonstrate the effect of the two factors.

5 ppt 35 ppt

5oC 54.7 44.9

25oC 36.4 30.7


FEATURE


is utilised for the production of energy, it is fully oxidised and the final products are: energy, carbon dioxide and water.

All these processes are included in the term of metabolism. The rate of metabolism is influenced by a large array of abiotic and biotic factors (see Table 2). From all these factors it should be underlined here that that activity is the most potent factor. Oxygen consumption is proportional to the metabolic rate, and it is therefore a common approach to measure metabolic rate by measuring oxygen consumption.

Temperature has a strong impact on oxygen requirements as it affects the activity of enzymatic processes. Besides the enzymatic processes, tem-perature has an effect on the ability of hemoglobin to bind oxygen and the solubility of membranes. Another important effect of temperature on metabolism is related to the amount of water bound by proteins. Water molecules are bound to polar groups in the protein molecule, and the amount of water is influenced by temperature. The effect of temperature is normally described by a Q10 value, which expresses the multiplication factor when temperature is increased by 10oC. Q10 receives a value between two and three in most cases.

When calculating the need for oxygena-tion it is important to know the average size of the fish comprising the population in question. As a general rule, per kg of biomass, smaller fish require much higher quantities of oxygen than larger fish.

Monitoring of oxygenation

Measurement of oxygen concentration in water usually takes place by use of an oxy-gen electrode, which was developed by Prof. Leland Clark in 1956. This basically measures an electric current, which is based on the reduction of oxygen at the cathode:

O2 + 2H+ + 4e- 2 0H-

Whereas at the

anode electrode sil-ver fells out of solu-tion:

Ag Ag+ + e- The sensitivity of

this type of oxygen sensor depends on the area of the cath-ode and thickness of the membrane of the sensor, which may limit the diffu-sion of oxygen to the cathode. It becomes evident from the equations above that the sensor in one way consumes oxygen, which is the parameter it actually measures.

To circumvent this practical problem, the sensor should be in motion in relation to the water. In prac-tical terms, this means that if the measure-ment is taken manu-ally by a technician, this person should shake smoothly the sensor in the water

until a stable value is established. In the case of a sensor mounted at a stable point, the measure-ments are of little value, in the case of standing waters or a container of water with low current.

The Clark type of oxygen sensor requires a current of at least five cm/s to function properly. In the case of currents in cages as shown in Table three, this value is not so easy to achieve, and stirring is necessary. To sum up, in the case of manual measurement, this type of electrode can function well, whereas if the sensor is mounted at a fixed point, the issue of current speed becomes an important issue.

The Clark-type of oxygen sensor - electrode requires frequent replacement of electrolyte and membrane, and frequent calibration. A relatively

Figure 2. A schematic diagram showing the respiratory pump. Water entering the mouth is further led by suction to the gill cavity and passes thereby through the gills. Opening and closing of the mouth and the opercular valve ensure that water flows in one direction.


FEATURE

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new technology has been developed based on the presence of a fluorescent compound in the sensor.

This methodology does circumvents several of the technical disadvantages of the previous method as it does not consume oxygen and stirring is therefore not necessary. These optic oxygen sen-sors are more expensive to purchase, but on the other hand have a lower maintenance cost.

Factors that may be influenced by insufficient oxygenation

It has been documented that the single most important factor for increased growth and productivity in aquaculture is to maintain sufficient oxygen saturation level over time in the water where the species grow. At saturation level below 85 percent, feed utilisation begins to fall and the fish is increasingly vulnerable to sickness and, in the end, mortality:- at 75% saturation reduced appetite starts to

appear- at 60% saturation increased mortality is shown- at 40% saturation there is no appetite among fish- at 30% saturation there is massive mortality.

Feed is composed of three main groups of food-stuffs: protein, fat, and carbo-hydrates. The amount of oxy-gen needed to metabolize a gram of food differs for these three groups of foodstuffs. Fat gives more than double the energy released during the catabolism of protein and car-bohydrates and at the same time requires a proportionally increased amount of oxygen to achieve this process.

It is logical to assume that fish consuming a fatty diet will have higher oxygen requirements compared with fish consuming a larger propor-

tion of carbohydrates. It has been postulated that decreased oxy-gen levels may have an impact on resistance of fish to infectious diseases (viral and bacterial dis-

eases), as in the case of channel catfish, Atlantic salmon and other species. Increased infestation of parasites has also been observed.

Basic principles in oxygenationInjection of a gas in aquaculture is governed

by certain principles which will be described here in order to make easy to perceive the limitations and possibilities related to oxygenation.

An important factor that influences efficient injection of a gas in water is the size of bubbles as they exit the diffuser. Small size show several advantages in related to larger ones. If gas is divided to small bubbles the contact surface with water is much higher than in the case of large bubbles. In a sphere, as the diameter increases the

ration of volume to external sur-face decreases.

This means that the content of large bubbles has fewer chances to dissolve in the water that the same amount of gas in small bubbles. It is needless to point out here that both in the case of oxygenation in tanks and in cages oxygen that reaches the surface of water and burst is a loss for the farmer as it enters the atmos-phere and is of no use for the fish farmed. If you thereby oxygenate your farm and notice the water “boiling” due to gas injected in the water, you should take it as warning that large amounts of gas are getting wasted.

Another disadvantage of large bubbles is that they rise fast in the water column to reach the surface and thereby remain for a reduced time in the water reducing further the ability of oxygen to dissolve. A further disadvantage of large bubbles is that large

bubbles show a tendency to “merge” and thereby becoming even larger increasing the problem.

From the description above it becomes clear that ideal oxygenation involves the formation of small bubbles, which rise slowly in the water column, and result in efficient oxygena-tion of the water as a maxi-mal interface of gas-liquid is provided. These tiny gas

bubbles give a “milky” appearance to the water.A second important factor is the distribution

of the gas in the cage or the tank. In the case of circular tanks, these are not so deep so the bubbles have a short distance to cover before they get dissolved so the need for small bubbles is quite high. On the other hand, as the water is well mixed compared with other systems a few areas of gas injection are sufficient to provide fish the necessary oxygen.

In earth ponds or in raceways it is impor-tant to inject oxygen in the area close to the entrance of the raceway so oxygen has higher chances to be utilised by the fish population. In the case of fish cages, oxygen has to be distributed over a large area. The gas can be injected at a larger depth than is usual in the case of tanks or ponds, so there is more distance to be covered in the water column

by the bubbles and thereby more time to achieve oxygenation over the water masses.

CagesThere is a widespread belief among farmers

that oxygen demands of fish farmed in cages at sea are under all situations covered by the currents existing at sea. It is easy however to determine at first that oxygen concentration inside the cages is lower than the oxygen concentration a few meters outside the cage (Figure 3). This difference is powered by two factors: (a) the consumption of oxygen within the cage, and (b) the ability of the current to replace the depleted oxygen with the fresh supplied brought by water rich in oxygen. The current in the area of the cages is much lower than the current outside the cages (Table 3).

It is obvious that the work of the currents is hindered in the case of cages placed in the sea by the net surrounding the cage. This net in the case of most farms in the Mediterranean is double to hinder the escape of fish. In addi-tion, the size of fish is smaller than for example is the case in salmon farming, so mesh size is on average smaller than in salmon farming. An additional problem that arises is the fouling of nets with micro- and macroalgae which reduces considerably the renewal of water and causes further problem in the cages.

In the case of farming of gilthead seabream and seabass, production is such that there is a peak of the total biomass towards late summer and autumn. The large biomasses in the on-growing cages results in increased demand for oxygen, where addition of oxygen in the cages by natural currents may not be sufficient, as the temperature is still quite high in autumn.

This type of oxygenation may be applied either after manual registration of low oxygen concentration in the cage or after continuous monitoring by an automatic system. An auto-

matic system for monitoring of oxygen level in the cages ensures that low levels at any time of the day or night will result in an alarm procedure, able to result in addition of oxygen within a reasonable time period. ■

Figure 3. Dissolved oxygen concentration outside and within a cage. The difference in oxygen level indicated an exchange rate between about 3-6 times/hour.

table 3: Parallel monitoring of current velocity at surface outside a farm and inside a cage.

Current outside farm (cm/s) 2-4 4-6 6-8 8-10 10-12

Current inside farm (cm/s) 1.7 1.7 2.1 2.2 2.2

reduction of current (%) 44 67 70 76 80

table 2: Factors that influence metabolic rate and consequently the oxygen requirements in fish.

abiotic factors Biotic factors

temperature activity level

Salinity Weight

oxygen oxygen debt

ammonia Stress

acidity Starvation

Season Quality of feed


FEATURE


Aquaculture reached a landmarkin 2009, supplying greater thanhalfofthetotal fishandshellfishfor human consumption (Naylor

et al. 2009).With global fisheries indeclineand human population increasing, the gapbetweenproteinsupplyandproteindemandis widening.Aquaculture must continue toexpandtomeetthesegrowingneeds,anditmustdosoinasafe,sustainablemannerthatdecreasestheworld’srelianceonharvestingfish for fishmealwhilestillproducingahighquality product. There are several difficulthurdles theaquaculture industrynow facesifthisneededgrowthistooccur.

These include, but are not limited to; the continued heavy reliance upon capture and reduction fisheries to supply fishmeal and fish oil as the major base components for aquatic feeds, build-up of con-taminants from these wild caught ingredients in the final products, and public perception that aquaculture in its current state is not sustain-able and is a detriment to local ecosystems (Naylor et al. 2009). Tacon and Metian (2009) reported that 36.2 percent of total worldwide catch in 2006 was destined for non-human consumption, meaning the reduction to fishmeal and fish oil for aquaculture diet formulation, the pet food industry, or as bait.

The aquaculture industry cur-rently consumes roughly 68.2 per-cent of global fishmeal production and 88.5 percent of global fish oil production (Tacon and Metian, 2008). These trends are not sustain-able given the state of the world’s fisheries and alternatives to fishmeal and fish oil must be found to ensure the sustainability and expansion of the industry as well as the conserva-tion of wild populations and ecosys-tems. Replacement of fishmeal and fish oil in aquaculture diets has been a goal for several decades but has met with limited success often due

simply to the cost and inconsistency in the quality and quantity of the product produced. Replacing fishmeal and fish oil for freshwater species without loss in production is easier to accomplish than it is with marine species.

This may be due in part to the fact that many freshwater fish are extensively cultured and enjoy a much deeper knowledge and experience base than their marine counter-parts, but it may also be a result of most freshwater species in culture being herbivores, omnivores, or scavengers in their natural systems. Most marine species that are sought for intensive culture on the other hand, are carnivorous, which precludes different dietary habits and requirements.

Our research has centered on replacing fishmeal with a blend of plant protein sources to completely eliminate the need for fishmeal

in diets for Cobia, Rachycentron canadum, and other high-value marine carnivores. Cobia are a highly carnivorous species (Franks et al. 1996; Arendt et al. 2001) found tropically and sub-tropically around the world except for the eastern Pacific, are highly fecund and can be spawned both naturally and through artificial induction in captivity, display rapid growth rates and high natural disease resistance, and are adaptable to a variety of culture and tank conditions (Holt et al. 2007).

This species is a prime target in the need to increase aquaculture production and serves as an excellent model species due to its rapid growth and limited competition from a wild fishery. Several physiological issues are presented however, with the use of plant pro-teins as opposed to other alternative protein sources such as animal meals. Digestibility of

Developing a plant-based diet for Cobia Rachycentron canadum by Aaron M Watson MSc, George Wm Kissil PhD, Frederic T. Barrows PhD, and Allen R. Place PhD The Institute of Marine and Environmental Technology, Baltimore, USA

table 1: Composition of diets used for determination of individual ingredient digestibility.

Diet

FM1 FM2 WG BM CG SPC SM WF

Component (g kg-¹)

Fish Meal 1 978 678 678 678 678

Fish Meal 2 978 678 678

Wheat Gluten 300

Barley Meal 300

Corn Gluten 300

Soy Protein Concentrate 300

Soybean Meal 300

Wheat Flour 300

algal Meal

Vitamin Pre-Mixa 14 14 14 14 14 14 14 14

Chromium oxide 8 8 8 8 8 8 8 8

Proximate Analysis (g kg -¹ DM)

Crude Protein 593 656 647 456 642 599 611 515

Crude lipid 165 95 191 103 75 77 73 73

ash 200 160 130 148 130 135 157 152

Gross energy (MJ kg-¹) 20.27 19.38 19.17 20.05 20.92 19.1 13.61 13.95

Contributed per kg diet; vitamin A, 13510 IU; vitamin D, 9.2 IU; vitamin E, 184.4 IU; menadione sodium bisulfite, 6.6 mg; thiamine mononitrate, 12.7 mg; riboflavin, 13.4 mg; pyridoxine hydrochloride, 19.2 mg; pantothenate, DL-calcium, 141.5 mg; cyanocobalamine, 0.04 mg; nictonic acid, 30.5 mg; biotin, 0.46 mg; folic acid, 3.5 mg.


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plant proteins, possible anti-nutritional factors present, palatability, and lack of essential amino acids all must be solved to successfully replace fishmeal with plant proteins. Digestibility can be examined on a species-specific basis, one protein source at a time as we have done with juvenile cobia utilizing an inert marker such as chromium oxide (Table 1).

This process involves feeding experimental diets containing a fishmeal base along with each individual protein source, gently stripping feces and analyzing them for protein, lipid, and energy content in relation to the concentra-tion of the inert marker, and comparing results to those obtained from diets only containing the fishmeal base (Lupatsch et al. 1997). Through this process, digestible protein, lipid,

and overall energy can be determined for the test ingredient. It is important to note how-ever, that the ability to digest plant proteins may be different at different developmental stages depending upon the species’ comple-ment of digestive enzymes and intestinal flora.

In our examination of six plant proteins (wheat gluten, barley meal, soy protein con-centrate, corn gluten, soybean meal, and wheat flour) with juvenile cobia (400-700g), only one plant source (barley meal) was deemed to have too low a digestibility to be considered a via-ble replacement candidate, with the rest of the plant proteins having digest-ibility’s similar to fishmeal sources (Table 2), indi-cating that for the most part, digestibility itself is not a primary obstacle. The lack of known essential amino acids from plant protein sources can easily be remedied by their addition during the for-mulation and manufacture of the diet, a com-mon practice in the industry already for lysine, methionine, and threonine, along with other com-ponents known to be lacking in fishmeal replace-

ment sources, or as additives simply to enhance growth, health, and palatability.

The biggest issues have arisen when attempting complete fishmeal replacement as opposed to simply reducing the amount of fishmeal utilized in favor of plant proteins. Many researchers and growers have encoun-tered lower growth and survival rates when reducing the percentage of fishmeal inclusion in diets for marine fish below 10-20 percent, depending on the species. There appears to be at least one essential component found in

Figure 1. Growth of juvenile cobia (30g initial weight) during 9 week growth trial. 120 fish per tank, 27°C, 25 ppt salinity. Average weight ± s.d.

Figure 2. Growth of juvenile cobia (120g initial weight) during 8 week growth trial. 60 fish per tank, 27°C, 25 ppt salinity. Average weight ± s.d.


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fishmeal and other animal meals that is lacking in plant sources that is responsible for the inability to formulate plant based diets with complete fishmeal replacement.

Taurine, an amino acid that is not incorpo-rated into any proteins but plays critical roles in lipid metabolism, oxidative stress responses, muscle activity, and photoreceptor protection (Schuller-Levis and Park 2003) is found in high concentrations in many tissue types in carnivorous fish and their prey (Satake et al. 1988), as well as fishmeal (Kim et al. 2005). Taurine is not found in high concentra-

tions however, in many fishmeal replacement sources, most notably plant protein sources such as wheat flour, soy protein concentrate, and corn gluten. Due to its water solubility, taurine is also often found in low concentra-tions even in fishmeal based diets and other fishmeal replacement sources, as large quanti-ties of taurine are often lost in the processing of these ingredients.

The re-addition of the stickwater by-product, which is high in taurine and other free amino acids, back to the manufacturing of diets has been shown to increase growth in Atlantic salmon (Kousoulaki et al. 2009). Several researchers have noted increased feeding and growth rates in marine fish fed diets supplemented with taurine, especially when attempting to replace fishmeal either partially or completely (Martinez et al. 2004, Matsunari et al. 2008, Lunger et al. 2007, Gaylord et al. 2007).

Based on the digestibility of the individual ingredients examined, two experimental plant protein based diets (EPP1 and EPP2) were formulated (Table 3) with equivalent protein (~45%) and energy (~20Mj Kg-1) digestibility to commercially available feeds. Grow-out trials were conducted at the Institute of Marine and Environmental Technology (IMET) in eight foot diameter, four cubic meter, recirculating systems sharing mechanical and bio-filtration as well as life support systems. Both trials were conducted at 27°C and 25 ppt, with 120 fish per tank in the first trial and 60 fish per tank in the second.

The results of the first growth trial with

EPP1 resulted in poor feed conversion, poor percent weight gain, and poor spe-cific growth rate (4.66, 199%, 1.09 respec-tively, Table 3). Top coating EPP1 pellets with attractants did not improve accept-ance. Fish being fed the commercial feed had normal perform-

ance indices (FCR 1.32% weight gain 900, and SGR 3.65) that indicated that this batch was healthy and grew at similar rates as other batches of cobia raised in our facility, and were larger upon completion of the trial (ANCOVA, p <0.001, with diet as covariate, Figure 1) than fish fed EPP1.

In the second trial with EPP2, a plant-based trout diet (Gaylord et al. 2007) was modified for use with marine spe-cies. The changes in formulation between EPP1 and EPP2 include reducing the lipid con-tent from 15 percent to eight percent, replac-ing barley meal with wheat flour because of the low digestibil-ity of barley meal, and replacing wheat gluten with solvent extracted soybean meal. Taurine was absent in the for-mulation of EPP1, and due to taurine’s known

table 2: apparent digestibility coefficients (aDC) of individual ingredients.

apparent Digestibility (%) Ingredient

FM1 FM2 WG BM CG SPC SM WF

Crude Protein 91 84 83 53 92 85 76 89

Crude lipid 97 91 52 16 37 25 29 32

Gross energy 90 84 62 27 86 43 38 37

DCPa (g kg-¹) 540 567 685 96 736 558 387 152

Dlb (g kg-¹) 155 85 24 5 19 5 6 6

Dec (MJ kg-¹) 18 15 13 5 19 9 7 6aDigestible crude protein, bDigestible lipid, cDigestible energy

table 3: Diet formulations and performance indices for plant based diets

Diet

Ingredient (g kg-¹) ePP1a ePP2b

Soy Protein Concentrate 364.3 269.3

Corn Gluten 201.0 211.0

Wheat Flour - 226.5

Barley Meal 104.5 -

Soybean Meal, Solvent extracted - 121.0

Wheat Gluten 82.3 -

Menhaden oil 146.0 84.0

Di-calcium Phosphate 40.7 23.7

Vitamin Pre-mixc 10.0 10.0

lysine-HCl 21.5 15.5

Choline Cl 6.0 6.0

trace Mineral Pre-mixd 1.0 1.0

Magnesium oxide 0.5 0.5

Stay-C 3.0 3.0

Dl-Methionine 3.4 5.8

threonine 2.1 2.1

Potassium Chloride 5.6 5.6

taurine - 15.0

Proximate Compositione Calculated Measured

lipid, % dm 15.1 7.87 ± 1.07

ash, % dm 4.5 4.98 ± 0.03 (5.15)

Protein, % dm 47.4 49.50 (47.3)

Carbohydrate, % dm by difference 32.67 35.14

Fiber, % dm (0.33) (2.51)

Moisture, % 5.3 7.14 (9.96)

energy Content, MJ Kg-1 20.7 19.30 ± 0.77

Performance Indices ePP1i ePP2j

FCrf 4.66 1.35

Weight Gain (%) 199 379

Hepatosomatic indexg nt 2.34 ± 0.001

Specific Growth rateh 1.09 2.36

Survival 95% 98%

aExperimental Plant Protein 1bExperimental Plant Protein 2cContributed per kg diet; vitamin A, 9650 IU; vitamin D, 6.6 IU; vitamin E, 132 IU;

menadione sodium bisulfite, 4.7 mg; thiamine mononitrate, 9.1 mg; riboflavin, 9.6 mg; pyridoxine hydrochloride, 13.7 mg; pantothenate, DL-calcium, 101.1 mg; cyanocobalamine, 0.03 mg; nictonic acid, 21.8 mg; biotin, 0.33 mg; folic acid, 2.5 mgdContributed in mg kg-¹ of diet; zinc 37; manganese, 10; iodine, 5; copper, 1eValues in parentheses were determined by New Jersey Feed Labs, IncfFeed conversion ratio (g fed/g gained)gLiver weight/body weight*100 ± standard deviationhSGR=specific growth rate= ((lnBW2-lnBW1)*(days of growth trial-1))*100iInitial Weight 30g, final weight 62g, 27°C, 25ppt, 8 week growth trialjInitial Weight 120g, final weight 572g, 27°C, 25ppt, 8 week growth trial


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physiological roles and that it has been shown to increase growth in a variety fish species (Gaylord et al. 2007; Kim et al. 2005a; Takagi et al. 2008), including cobia (Lunger et al. 2007), it was included in the formulation of EPP2 at 1.5 percent.

Fish fed EPP2 performed better than fish fed EPP1, with better feed conversion, higher percent weight gain, and higher specific growth rates (1.35, 379 percent, 2.36 respec-tively for the EPP2; Table 3), even given the larger starting size of individuals in the second trial. Fish fed the commercial diet during the second trial had significantly lower growth (FCR 1.85, percent weight gain 255, and SGR 1.93) and were smaller upon completion of the trial compared to those from EPP2 (ANCOVA, p=0.018, with diet as covariate, Figure 2).

During the first growth trial with diet EPP1 fish grew very poorly as evidenced by the slow growth rate and high feed conversion. This poor performance clearly suggests an issue outside of protein digestibility since several highly digestible protein sources are included in the blend. Although poor palat-ability is another possibility, the addition of feeding stimulants to EPP1 did not alter feed-ing behavior.

Growth on EPP2 resulted in much higher feeding rates and greatly increased perform-ance characteristics such as fillet yield and lower feed conversion ratios (Table 3). Fish in the other tank of the paired system being fed the in-house, commercially available feed had slightly and significantly lower FCR, SGR, and percent weight gain from 120g to 355g during the trial. Growth and FCR observed on EPP2 are equivalent to results found by other researchers with various sizes of juvenile cobia, using diets based on fishmeal as well as several fishmeal replacement trials (Lunger et al. 2007; Salze et al. 2010).

Although there were several differences in the plant protein blends used for the two experimental diets in the current study (barley meal and wheat gluten in EPP1 replaced by wheat flour and soybean meal in EPP2) other differences in the two formulations include the addition of taurine and reduced lipid content of EPP2. Due to the roles that taurine has been shown to play, such as a possible feed attractant (Brotons Martinez et al. 2004) and its involvement in bile salt conjugation (Kim et al. 2007), it is our opinion that the

most important difference in the formulations of the diets in this study is the addition of taurine to EPP2. Taurine is not incorporated into any known proteins and therefore is only considered semi-essential in most species but is considered essential for at least one strict carnivore, felines.

The findings from the digestibility portion of our study demonstrate that several plant protein sources are highly digestible and suita-ble fishmeal replacements for cobia, which are strict carnivores. The results of the grow out trials present evidence that taurine needs to be added to diets for carnivorous marine fish-es, especially when attempting to completely replace fishmeal with alternate sources that may be naturally devoid of taurine. In addition, the growth rates observed with EPP2, an eight percent lipid diet, were equivalent to growth seen on the commercial diet, a 15 percent lipid diet, indicating that cobia may be able to utilise lower lipid diets, helping to reduce the overall cost of feed required to reach market size. Interestingly, regardless of lipid content of the diet, fillets from fish fed either EPP2 or the commercial diet maintained equivalent lipid levels within their fillets (~12-13 percent dry weight).

Upon completion of these pilot-scale trials, several more questions involving the use of plant proteins and taurine have arisen that are currently being examined in our lab with juvenile cobia as well as other high-value species such as gilthead seabream and striped bass. The next hurdles are to determine what the effects may be on the final fillet in terms of taste and texture when eliminating fishmeal in favor of plant proteins. Can the fish oil com-ponent of the diet also be replaced without detrimental effects to production character-istics or final fillet quality? Will raising farmed fish on plant-based diets reduce contaminants such as mercury and PCB’s that are known to accumulate in fish raised on traditional, fishmeal based diets as well as found in wild-caught fish brought to market? Is taurine an essential amino acid for marine carnivores?

Although our research is now focused primarily on taurine and its biosynthesis path-way in an effort to establish taurine as an essential amino acid for marine carnivores, encouraging results to all of these questions have been obtained in our work so far. This work, and that of many others in the field is indicating that complete fishmeal replacement

is possible with marine carnivores in intensive aquaculture systems. Reducing the industry’s reliance upon the reduction fisheries to supply fishmeal and fish oil for diets will not only allow the needed expansion of aquaculture to supply the world’s growing protein demands, but will also immensely benefit the recovery and sustainability of the oceans forage and food fishes and the ecosystems that have decimated by decades of over fishing and poor fishing practices. ■

Acknowledgements

The authors would like thank the staff of the Aquaculture Research Center at the Institute of Marine and Environmental Technology; Steve Rodgers, Chris Tollini, and Joy Harris as well as Matteo Avella, Gordon Taylor, and Michele Thompson for assistance in the digestibility trials and analysis. Special thanks, to Ernest Williams for laboratory assistance throughout the study and Jason Frost, USDA/ARS for assistance in manufacturing of the experimental diets.

This work was funded by award #NA080AR4170821 from the NOAA National Marine Aquaculture Initiative. Parts of this work have also been featured on Earth Focus @ linkTV; http://www.linktv.org/video/6868/oceans-turning-the-tide

About the Authors

Aaron M. Watson MSc

Allen R. Place Ph.Da Institute of Marine and

Environmental Technology University of Maryland Center

for Environmental Science 701 East Pratt St. Baltimore, MD 21202. USA.

George Wm. Kissil Ph.D

Israel Oceanographic and Limnological Research National Center for Mariculture, Eilat, Israel.

Frederic T. Barrows Ph.D

U.S. Department of Agriculture Agricultural Research Service, Hagerman Fish Culture Experiment Station Hagerman, ID 83332, USA.


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The world demand for seafood isincreasing dramatically year by year,although an annual upper limit of100million tons is set soasnot to

exhaustreserves.Itisforthisreasonthatthereis a considerable move towards modernisingandintensifyingfishfarming.Tobeeconomicallyviable,fishfarmingmustbecompetitive,whichmeans that feed costs amongst others mustbecarefullymonitoredastheoperationalcostgoes 60 percent for feed alone. Thereforeselection of cheaper and quality ingredientsis of paramount importance for sustainableand economical aquaculture. Identification ofsuitablealternateproteinsourcesforinclusionin fish feeds becomes imperative to counterthescarcityoffishmeal.

In addition to its scarcity and high cost, often fishmeal is adulterated with sand, salt and other undesirable materials. All these factors have forced fish feed manufactures all over the world to look for alternate sources. In this context they have been left with no protein but to substitute animal protein with plant protein sources. A variety of plant protein sources including soybean meal, leaf protein concentrate and single cell protein have been tested. The tests have shown that these can be included as alternatives to fishmeal (Ogino et al, 1978, Appler and Jauncy, 1983).

Of various plant protein sources, soybean meal (SBM) is one of the most promising replacements for part or whole of fishmeal. Soybean meal is the by-product after the removal of oil from Soya beans (glycine max). At present soybean meal is the most important protein source as feed for farm animals and as partial or entire replacement of fishmeal?

The products obtained from soybeans and their processing are as follows:-

• Soybean meals, solvent extract• Soybean meal from dehulled seeds, sol-

vent extracted,• Soybean expeller• Soybean expeller from dehulled seeds• Full fat soybean meal• Full fat soybean meal from dehulled seeds

The chemical composition of soybean meal is fairly consistent (Figure 1).

The crude protein level depends on the soybean meal quality. Soybean has one of the best amino acid profiles of all vegetable oil meals. The limiting amino acids in soybean meal are methionine and cystine while arginine and phenylalanine are in good supply (New, 1987).

The fat content of the solvent extracted soy-bean meal is insignificant but soybean expeller has oil content between six and seven percent, while full fat soybean expeller has oil content between 18 to 20 percent. Soybean meal and soybean expeller are lower in macro and trace elements than fishmeal. There is no substantial difference between the indi-vidual soybean meal products. The calcium content is low and the phosphorus level is rather higher. However, the phospho-rus is bound to phytic acid and its availability for aquatic animals is, therefore, limited.

Soybean meals and expel-lers are reasonable source of B-vitamins. For most vitamins there are insignificant differences between the different products. However the full fat soy-bean meal tends to be higher in some vitamins. While the products are mainly higher in choline content, the vitamin B12 content is low and pan-tothenic acid is mainly damaged by heat treatment.

The digestible energy of soybean meal over all fish species ranges from 2572 to 3340 Kcal/kg (10.8 to 14.0 MJ/kg). The metabolisable and digestible energy of full soybean meal increases with the increase heating temperature at a given time due to the inactivation of trypsin inhibitors.

Deleterious constituents of soybean products

Trypsin inhibitors: - About six percent of the total protein of soybeans reduces activities of trypsin and chymotrysin, which are pancreatic enzymes and involved in protein digestion (Yen et al., 1977). The activity of trypsin inhibitor is not fully understood, but is responsible for the poor performance of certain fish species (Alexis et al., 1985, Balogum and Ologhobo., 1989).

Lectins: - This type of toxic protein is chemi-cally hem agglutinin, which causes agglutination of RBC's (Liener, 1969). There are indications that lectins reduce the nutritive value of soybean meal for Salmonids but are inactivated by treat-ment of the meals (Ingh et al, 1991).

Other properties: - Soybean is unpalatable for some fishes such as Chinook salmon. While as herbivorous and omnivorous species are less choosy. The size or age of the fish may also affect the palatability of soybean meal.

Utilisation of Soybean Products in Aquaculture

Comprehensive research work has been done to evaluate soy-bean meals as a replace-ment of animal protein sources in diets for fishes but the replacement of all fishmeal by soybean meal has not been very successful perhaps due to the limiting amino

acids and insufficient heat treatment of the soy-bean meals. Smith et al (1980) claimed success in feeding rainbow trout a diet based almost entirely on raw materials of vegetable origin containing 80 percent full fat roasted soybean. In a similar report, Brandt (1979) evaluated a diet based entirely on plant ingredients (containing 50 percent heated full fat soybean + 10 percent maize gluten meal to overcome a possible defi-ciency of S-amino acids).

Reinitz et al (1978) observed that rainbow trout fry fed a diet containing 72.7 percent full fat soybean had a greater daily increase in length and weight with an improved feed conversion ratio compared with those fed a control diet based on 25 percent herring meal, five percent fish oil 20 percent soybean oil meal. The mortal-ity rate for both groups was similar. Taste panel studies indicated that there was no effect of dietary treatment on firmness and flavour of the fish.

Kaneko (1969) reported that 1/3rd of white fishmeal could be replaced by soybean meal with no negative effects on growth of warm

Use of soybean products in aquafeeds: a reviewby T. H.Bhat, M. H.Balkhi and Tufail Banday (Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir)

Figure 1: The chemical composition of Soyabean meal


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water fishes. Viola (1977) iso-nitrogenously reduced the fishmeal content in the diet of carps containing 25 percent protein supplemented by soybean meal with the addition of amino acids, vitamins and minerals and opined that soybean diet did not induce good growth in carp. Similarly Atack et al (1979) reported poor utilisation of soybean protein by carp when it formed the sole protein source. Gracek (1979) used different qualities of soybean meal to sup-plement ground maize for feeding carp fry and recorded better survival.

No difference in growth was observed when common carp (Cyprinus carpio) were fed either with 45 percent soybean meal (+10 percent fishmeal) or 20 percent soybean meal (+22 percent fishmeal). Other trails however showed that the growth performance and feed efficiency of common carp were reduced when dietary fishmeal was replaced by soybean meals.

There were no differences in performance between extruded full fat soybean meal and oil reconstituted soybean meal (Inghet et al; 1991). A better weight gain was reported when soybean meal was incorporated in the diets of carp fish (Cristoma et al; 1984). Similarly sklyrov et al (1985) successfully used soybean meal in rearing carp fish commercially. It is claimed that soybean meal is deficient in available energy and lysine as well as methionine for carps. Supplementation of soybean meal diets with methionine coated with aldehyde treated caesin significantly improved utilisation of amino acid by common carp (Murai et al; 1982).

Lack of phosphorus rather than the sulphur amino acids may be the cause for poor perform-ance of common carps when 40 percent soy-bean meal diets were fed to them. Addition of 2.0 percent sodium phosphate did not improve their performances (Viola et al; 1986). Kim and Oh (1985) attributed the poor performance of common carp fed with a diet containing 40 percent soybean to lack of phosphorus rather than sulphur and amino acids, since addition of two percent sodium phosphates to soybean meal diet improved their performance to a level obtained with the best commercial feed.

Nour et al (1989) studied the effect of heat treatment on the nutritive value of soybean meal as complete diet for common carp by autoclaving the soybean seeds for 0, 15, 30, or 90 minutes and recorded maximum average daily weight gain with diets containing soybean seeds autoclaved for 30 minutes. Nandeesha et al (1989) incorporated soybean meal in the diets of Catla and indicated the possibility of utilising soybean meal in carp diets.

Keshavapa et al (1990) used soybean flour in the diet of carp fry and recorded better survival. Senappa (1992) studied protein digestibility from soybean-incorporated diets and recorded better digestibility when fed to fingerlings of Catla. Naik (1998) studied the effect of Soya flour and fishmeal based diets in the diet of Catla catla & Labeo rohita and observed a better growth and

survival of carps when reared together and also in combination with fresh water prawn.

Channel cat fish (Ictalurus punctatus) fed on all plant protein diets grew significantly less than fish fed diets containing fishmeal (Lyman et al, 1944). Growth was substantially reduced when menhaden fishmeal was replaced by soybean meal at an isonitrogenous basis (Andrews and Page, 1974). Full fat soybean meal heat treated differently replaced fishmeal at low levels in diets for channel cat fish showed that replacement gave satisfactory results (Saad, 1979).

Growth and feed efficiency of fingerling hybrid tilapia (Oreochromis niloticus) was significantly depressed when soybean meal replaced fishmeal at the optimum level (30 percent) in their diet (Shiau et al, 1988). The growth depression of the hybrid tilapia was reduced when a 30 percent crude protein diet containing soybean meal but by adding two to three percent dicalcium phosphate to the diet, growth rate of tilapia was comparable to the control (Viola et al, 1986). Soybean meal with supplemental methionine could replace up to 67 percent fishmeal in the diets for milk fish (Chanos chanos) (Shiau et al, 1988).

Growth, feed conversion and survival of tiger prawn (Penaeus monodon) juveniles fed two levels of soybean meal under laboratory conditions were lower with higher levels of soybean meal (Piedad, Pascual and Catacutan, 1990). No significant differ-ences in growth and survival could be established when soybean meal at levels from 15- 55 percent replaced par-tially or completely fish meal in the diets for tiger prawns stocked in cages in ponds at 10 to 20 shrimps per square meter (Piedad, Pascual et al, 1991). Lim and Dominy(1991) obtained compara-ble results in feeding Penalus Vannamel with diets containing up to 17 percent of dry extruded full fat soybean meal as a partial replacement for fish protein.

Generally the studies outlined above together with several others indicate that there is an advantage to be gained from using properly processed soybean products for formulating diets for fish due to their better quality protein

and higher dietary energy value in full fat soybean which is more advantageous with cold water fish species because warm water fish (Carp, Catfish etc) can utilise carbohydrates more efficiently. The only recommendation relating to the limit of inclusion of full fat soybean in fish diets is not to exceed the known practical limits relating to fats in general in order to avoid problems of feed preparation and to reduce the risk of high fat levels in the meal.

Recommended Inclusion RatesSoybean may replace animal protein in diets for

aquatic animals to a certain extent. However, with increasing substitution of e.g. fish meal by soybean meal the performance of fish decline. Herbivores may tolerate higher levels of soybean meal than carnivores. It appears that full fat soybean meal is more beneficial for cold-water fish than for warm water species due to the better utilization of the energy from the soybean products. Only properly heat-treated soybean products should be used for aquatic feeds. Furthermore, it is advisable to use only soybean meals processed from dehulled seeds in order to reduce the crude fisher content in the diet. ■

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FEATURE

Aquaculture UK 201223-24 May 2012

Aviemore, Scotland

The UK’s major Aquaculture exhibition and conference

featuring the latest aquaculture products and innovations.

Visit www.aquacultureUK.com for further information or

contact [email protected]

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BOOKSHOP

Perendale Publishers Ltd, the publishers of Grain & Feed MiIling Technology and International Aquafeed, has set up an online Amazon-based ‘Book Shop’ that lets you browse a wide range of recently-published reports and books on related topics. You can now read an extended review before making your selection and purchasing directly from Amazon.

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This book was edited by Stig S. Gezeliusfrom the Norwegian AgriculturalEconomics Research Institute (NILF),Oslo, Norway and Professor Jesper

Raakjær Innovative Fisheries Management (IFM),Hirtshals,Denmark.

The project was carried out over a two-year period from January 2006 to March 2008.

This book is a combination of many authors and researchers with all the information being finally edited by Stig S. Gezelius and Professor Jesper Raakjær.

Fisheries is an emotive subject, especially now in the 21st Century, with the declining stocks and still many oceans being overfished. In this book the authors have used Norway as an example of a fisheries management system.

A country that has 7000 fishing vessels spread along a 20,000km of coastline and the use of surveillance and enforcement in Norway’s control of its fisheries.They highlight the difficulties of many coastal states of the European Union and their approaches to the management of fisheries, using Total Allowable Catch (TACs), Individual Transferable Quotas (ITQs) along with other systems of control and enforcement. The following list shows contents by section:

1 The Problem of Implementing Policies for Sustainable Fishing

2 The Arrival of Modern Fisheries Management in the North Atlantic: A Historical Overview

3 Implementation of Resource Conservation Policies in the Norwegian Fisheries: A Historical Outline

4 From Catch Quotas to Effort Regulation: Politics and Implementation in the Faeroese Fisheries

5 Recovery Plans and the Balancing of Fishing Capacity and Fishing Possibilities: Path Dependence in the Common Fisheries Policy

6 Implementation Politics: The Case of Denmark Under the Common Fisheries Policy

7 The Politics of Implementation in Resource Conservation: Comparing the EU/Denmark and Norway

Conservation plays a pivotal role in modern fisheries, and in recent times we have seen a move to stop extreme waste by fishermen in the use of discards. This book has a lot to offer in the understanding of the fisheries, and the regulations used to enforce and control not just from a modern perspective but an historical one too. I think this is a book worth reading for anyone with an interest, in fisheries and fisheries regulations, students of marine conser-vation but also for those in the unique position to be involved in this industry as a fisherman or a fisheries inspector. A great read with a lot of good solid information.

Making Fisheries Management Work ISBN:978-1-4020-8627-4

BOOK REVIEW

Methods in Reproductive Aquaculture

Methods in ReproductiveAquaculture, published in 2009included some 80 authors whocontributed materials. The book

was edited by: Dr Elsa Cabrita, a researcherassociate in the Spanish National ResearchCouncil ICMAN-CSIC, Spain; Dr VanesaRobles, a researcher associate in theCentreofRegenerative Medicine in Barcelona CMR(B),Spain and Dr Paz Herráez, Professor in the

Department of Molecular Biology at theUniversityofLeón,Spain.

The aim of the book was to cover aspects that are considered important in the reproduction

of marine and freshwater species. The book is split into five sections to make the information contained more easily under-standable. Sectionone - chapters one and two: reviews basic methods and techniques for gamete extraction, spawning stimulation and strip-ping.Sectiontwo - chapters three and four: looks at sperm and egg

quality and is focused on gamete characteristics and methods used to evaluate quality.Section three - chapter five: deals with artificial fertilization in aquaculture species: from normal practice to chromosome manipulation.Section four - chapters six to 10: is a review of methods and advancements in gamete and embryo preservation and storage.Section five - this section describes specific protocols for the cryopreservation of sperm from several species. Sperm cryo-preservation protocols are detailed for fifty-six species, several marine, freshwater, anadromous and catadromous species of teleosts, chondrosts, molluscs, decapods or equinoderms.This is a well-written and well laid out book, giving informa-tion on endangered species and species that are important in aquaculture, as well as species with high potential in labora-tory research. Each section is laid out in an easy-to-read format with excel-lent descriptions. I think this is a must have book to anyone who works in the field of aquaculture and marine species reproduc-tion. A must have book for fish farmers, scientific researchers, students and teachers, an excellent book.

ISBN:978-0-8493-8053-2


INDUSTRY EVENTS

EventsKey:

*=Seeourmagazineatthisshow

•=Moreinformationavailable

EVENTS20122nd-3rdFebruary12 *Aquafeed Platform AMERICAS 11th Practical Short Courses: Trends and Markets in Aquaculture Feed Ingredients, Nutrition, Formulation and Optimized Feed Production and Quality Management, Costa Rica Marriott Hotel San Jose, Costa Rica

Contact:SefaKoseoglu,Filtration&MembraneWorldLLC309-C,ManuelDriveCollegeStationTX77840(U.S.A)

Tel:+19797648360Fax:+19796947031Email:[email protected]:www.smartshortcourses.com

7th-9thFebruary12 *EuroKarma 2012, MTPolska CenterUl. Marsa 56 c, 04-242 Warszawa, Poland

Contact:AgnieszkaNiemczewska,POBOX73,32-332Bukowno,Poland

Tel:+48514544048Email:[email protected]:www.eurokarma.eu

8th-9thFebruary12 *Ildex Bangkok, BITEC, Bangkok International Trade & Exhibition Centre, Bangkok, Thailand

Contact:Mr.JobeSmithtun,N.C.C.ExhibitionOrganizerCo.,Ltd.,(NEO),60NewRachadapisekRd,Klongtoey,Bangkok10110–Thailand

Tel:+6622293000Fax:+6622293001Email:[email protected]:b:www.ildex.com

15th-17thFebruary12 *FIAAP, Victam & GRAPAS Asia 2012, BITEC, Bangkok, ThailandContact: Andy West, Victam International, P O Box 411, Redhill, RH1 6WE, United Kingdom

Tel:+441737763501Email:[email protected]:www.victam.com

22nd-24thFebruary12 *VIV/ILDEX India 2012, BIEC centre, Bangalore, IndiaContact: Guus van Ham, PO Box 8800, 3503 RV Utrecht, The Netherland

Tel:+31302952302

Fax:+31302952809

Email:[email protected]

Web:www.viv.net

28thFebruary-3rdMarch12*Aquaculture America, Las Vegas, USA

Contact:JohnCooksey,POBox2302,ValleyCenter,CA92082,USA

Tel:+17607515005Fax:+17607515003Email:[email protected]:www.was.org

22nd-24thMarch12 *Ildex Vietnam, The New Saigon Exhibition and Convention Center (SECC), Ho Chi Minh City, Vietnam

Contact:Mr.JobeSmithtun,N.C.C.ExhibitionOrganizerCo.,Ltd.,(NEO),60NewRachadapisekRd,Klongtoey,Bangkok10110–Thailand

Tel:+6622034241Fax:+6622034250Email:[email protected]:www.ildex.com

22nd-24thMarch12 *Fishing, Aquaculture & Seafood Expo, Scottish Exhibition & Conference Centre (SECC), Glasgow, UK

Contact:CharleneHarris,SECC,ExhibitionWay,Glasgow,G38YW,UK

Tel:+441415763253Email:[email protected]:www.fasexpo.com

1st-4thMay12 *Skretting Australasian Aquaculture 2012 International Conference and Trade Show, Melbourne Convention Centre, Australia

Contact:Sarah-JaneDay,POBox370,NelsonBayNSW2315,Australia

Tel:+61437152234Fax:+61249841142Email:[email protected],auWeb:www.australian-aquaculture-portal.com

23rd-24thMay12 *AQUACULTURE UK 2012, Macdonald Highland Resort, Aviemore, UK

Contact:DavidMack,Rosebank,AnkervilleStreet,TainIV191BH,UK

Tel:+441862892188Email:[email protected]:www.aquacultureuk.com

1st-5thSeptember12 *Aqua 2012, Prague, Czech Republic

Contact:MrMarioStael,Marevent,Begijnengracht40,9000Gent,Belgium

Tel:+3292334912Fax:+3292334912Email:[email protected]:www.marevent.com

24th-25thOctober12BioMarine London 2012 - Business Convention, Fishmongers Hall, London, UK

Contact:PierreErwes,ChairmanBioMarineandCEOBioTopicsSAS,France

Tel:+33678078284Email:[email protected]:www.biomarine.orgWeb:http://convention.biomarine.orgLinkedIn:http://ca.linkedin.com/in/biomarineTwitter:http://twitter.com/#!/BioMarineTwitts

13th-16thNovember12 *EuroTier 2012, Hannover / Germany

Contact:DrKarlSchlösser,DLG,EschbornerLandstrasse122,60489Frankfurt/Main,Germany

Tel:+496924788259Fax:+496924788113Email:[email protected]:www.EuroTier.com

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‘ t h e n e x t t e n y e a r s ’

INDUSTRY EVENTS

Seafood is recognised as impor-tant in the diet and as an imper-ative for solving hunger issues

for the growing global population, but wild fisheries quantities have been maximised and aquaculture is not growing at the speed it needs in order to meet global demand for marine proteins.

That’s the dilemma put to the BioMarine 2011 ‘Think Tank on Aquaculture’ in Nante, France, late last year.

It found that, change could only be brought about via a culture change in terms of working across scientific and technology disciplines and sharing knowledge and experience to increase aquaculture opportunities through the three pillars of sustainability - environ-ment, economic and social.

BioMarine Business Convention was attended by over 200 CEOs of bio-technology companies, senior business development and licensing executives, public and private equity investors, research analysts, investment bankers and senior-level industry executives focused on investment trends and business development opportunities in marine bioresources.

The Think Tank on Aquaculture’s report stated, “We will aim to foster the creation of new interdisciplinary teams who focus on the proposed themes under the areas of aquacul-ture governance, aqua-feed, safety and regulation, environment and sustain-able development and promotion/marketing.”

It said that aquaculture, being one of the most relevant activities in marine bio resources and simultaneously one of the fastest growing primary industry sectors must undoubtedly evolve in a more sustainable way. This evolution is a very complex process that must be seen by all its players as essential and urgent, from designers and policy makers to all end users, implying changes in behavior, business models, and partnerships, cultural, social and political patterns.

“The synergy of networking, thinking outside the 'box', creating ideas through our passion and energy will benefit us all, and the world will be a

better place for our input and con-clusions.”

Governance SelfGovernance- Be pro-active. Be the driver of Standards e.g. retailer. Impose our own standards rather than have them imposed upon us. Simplifylegislation- Framework in EU as first step as far too many barriers. Create the Strategy for development in aquaculture enabling industry pro-ductivity. KnowledgeManagement- Ensuring that science supporting policy is a com-mitment. Use European Aquaculture (EATIP) Communication- Covers all areas but communication strategy is essential to government, industry, stakeholders, NGO‘s, Consumers, etc. Build the trust and goodwill. Think globally.

Feed Promotethebenefitsofthehealthoffeeds- Transparency in the feed chain right down to macro ingredients is essential. Omega-3 long chain essen-tial fatty acids are essential.

Growing fish on marine algae needs to be promoted over usage of land planted products.

“However, we strongly support the development of any and all types of algae or land based sources of long-chain fatty acids and essential oils that can substitute for fish-based feeds ingredients,” says the report. Functionality- Increase knowledge and information about functionality of feeds. Reduce antibiotic usage Animalrawmaterials- Revisit usage of these items in scientific manner and research opportunity Communication- Better information to be supplied to end users especially on feed ratios and comparisons with land animals

Safety and regulation Simplifyregulation- Too many regula-tions, hard to keep up. Unifywithglobalperspective- Maximum effort to get Governments working together to find efficiencies Environmental,Antibiotic,Chemicals- Pollution effecting health is an issue.

Unified Standard methods for testing and protocols Trainingstaff- Streamline and make cost efficient without losing emphasis.

Environmental sustainable development Definesustainability- Agree on a def-inition that accepts impact. Sustainable impact as a tradeoff of higher output in food production

If we get a globally agreed definition we can find solutions. Do not let the opposition define sustainability. Impacts–inputsandoutputs

Honest introspection. Involve stake-holders. Treat water without longterm disadvantages. Feed sources. Create business model of integrated aqua-culture. Gaps between offshore and coastal aquaculture Useallofourtools–nolimits

Do not narrow future develop-ment by restricting use of whatever tools there are. We need all the tools to protect the environment and maximise production in sustainable fashion

Maximize sustainability – promote not constrain

Aquaculture has different starting point to other agriculture industries. If they were forced to start today they might not be in business. Need to understand we are shaping a new industry where customer demands are highest ever seen in this area.

Regulation and Governmental Agencies focus should be on pro-moting sustainable business models rather than constraining industrial development. If through regulation, there is creation of economic value associated to sustainable practices, then the industry will naturally migrate towards sustainability.

Good transparent Sciences In the quest for sustainability, all tech-

nologies and scientific inquiries should be evaluated on their merits, and none prejudged as to efficacy or suit-ability

Marketing & Promotion Communication&Education

Battle the misconceptions/mis-information with factual informa-tion · Accurate, transparent informa-tion Bewillingtoengageindialogue

“We should be proud of history (Aquaculture started in 6000BC) as well of our achievements and we need to spread the messages. Suppor t and promote research which can answer critical claims. Encourage research that can further the (and rise the) level of the dialogue on the sustainability and positive aspects of aquaculture,” says the report.

Proactive An example is www.gillseafood.

org a website which covers all issues regarding seafood and health and is being driven by universities. It will be in several languages. Global Initiative for Life and Leadership through Seafood (GILLS) establishment of website.

“Where to from here? We need to find a solution of bringing industry groups together globally,” concludes the report.

The next BioMarine Business Convention is being organized for London from October 24-25, 2012. Space at the convention centre – Fishmongers Hall, London - is limited to just 200 delegates.



ThinkTankonAquaculture Buildingproductiontomeetincreasingdemand

by Roy Palmer, SEA; IAFI, WAS-APC and Aquaculture without Frontiers, Australia


The AquaculturistAregularlookinsidetheaquacultureindustry

http

://th

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We here at Perendale Publishers Limited wish all our readers a happy new year and we hope that 2012 is a year of growth and development and success. In the coming year we will be delivering news stories, features and stories of interest to the aquaculture industry. News doesn't happen on the days that suit our magazine's publishing dates,

nor do they take account of our postal delivery. Thats why we put in significant effort into our maintain our blog on a daily basis so that you the reader of IAF, can be kept up to the minute on developments and news that happens in and around our industry no matter where you are. Why not sign up to our news service its free. Why not let us deliver these short news items direct to your business or social website account? Just visit our blog and click the link to sign up. I'm here to keep you informed. I look forward to welcoming you to our service! you can find our blog at http://theaquaculturists.blogspot.com/

Hi my name is Martin Little. I am the Aquaculturists, with a background in Marine Zoology and eight years working in the field as a consultant fisheries observer in the North Atlantic, I am now part of International Aquafeed magazine, and as well as my column in the pages of the magazine I will be running an accompanying blog that can be found at http://theaquaculturists.blogspot.com/


www.viv.net

VIV/ILDEX India2012

February 22 - 24, 2012

Your portal to India’s Feed to Meat trade

Bangalore, India

Feedtech Croptech

The dedicated event for theIndian Milling industries

Special theme

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Register now for free entrance!

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EDICIONESPANOLA

Alltech = http://www.alltech.com

Amandus Kahl GmbH & Co = http://www.amandus-kahl-group.de

Andritz Feed & Biofuel = http://www.andritz.com

Biomin Holding GmbH = http://www.biomin.net

Buhler AG = http://www.buhlergroup.com

Dinnissen BV = http://www.dinnissen.nl

Empyreal 75 = http://www.empyreal75.com

Extru-Tech Inc = http://www.extru-techinc.com

Format International = http://www.formatinternational.com

Geelen Counterflow = http://www.geelencounterflow.com

Griffin Industries Inc = http://www.griffinind.com

Leiber GmbH = http://www.leibergmbh.de

Muyang Group = http://www.muyang.com

NK Chemicals Pte Ltd = http://www.nkchemicals.com.sg

Nutri-Ad International nv = http://www.nutriad.net

Ottevanger Milling Engineers B.V. = http://www.ottevanger.com

Reed Mariculture = http://www.reedmariculture.com

Rubinum SA = http://www.rubinum.es

SCE nv, Silo Construction & Engineering = http://www.sce.be

Sino-Aqua Corporation = http://www.sino-aqua.com

Storvik Limited = http://www.storvik.no

Wenger Manufacturing Inc. = http://www.wenger.com

YSI Incorporated = http://www.ysi.com

Zhengchang Group (ZCME) = http://www.zhengchang.com

48 |

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2012

Innovations for a better world.

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Fatten up your bottom line. Bühler high-performance animal and aqua feed production

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costs and increases capacity utilization. To find out more, visit www.buhlergroup.com

Visit us at Victam Asia 2012 in Bangkok, Thailand, booth A071 (15 - 17 February 2012)

Aqua_Feed-Jan_2012.indd 1 23.12.2011 14:28:03

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January | February 2012 - International Aquafeed