Chicken Meat - · PDF filePoultry Industry S G Heilbron and J T ... DAN-142A Production of distance learning materials for the ... and in forward planning of chick placements onto

RIRDC Completed Projects in 1998-1999 and Research in Progress as at June 1999

Sub-Program 3.1

Chicken Meat

August 1999 RIRDC Publication No 99/129

ii

© 1999 Rural Industries Research and Development Corporation. All rights reserved. ISBN 0 642 57930 X ISSN 1440-6845 "RIRDC Completed Projects in 1998-99 and Research in Progress as at June 1999 - 3.1 Chicken Meat" Publication No 99/129 The views expressed and the conclusions reached in this publication are those of the author and not necessarily those of persons consulted. RIRDC shall not be responsible in any way whatsoever to any person who relies in whole or in part on the contents of this report. This publication is copyright. However, RIRDC encourages wide dissemination of its research, providing the Corporation is clearly acknowledged. For any other enquiries concerning reproduction, contact the Communications Manager on phone 02 6272 3186.

RIRDC Chicken Meat Research Manager Dr Vivien Kite RIRDC Level 1, AMA House 42 Macquarie Street BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 9929 4077 Fax: 02 9925 0627 Email: [email protected] RIRDC Publications Manager Rural Industries Research and Development Corporation Level 1, AMA House 42 Macquarie Street BARTON ACT 2600 PO Box 4776 KINGSTON ACT 2604 Phone: 02 6272 3186 Fax: 02 6272 5877 Email: [email protected] Website: http://www.rirdc.gov.au

Published in August 1999 Printed on environmentally friendly paper by the AFFA Copy Centre

iii

Foreword This year RIRDC has produced Research in Progress, June '99, which contains short summaries of continuing projects as well as those that were completed during 1998-99 for all of the Corporation’s 20 program areas. The complete report on all the programs is only available in electronic format on our website at http://www.rirdc.gov.au The following report is a hardcopy extract covering Sub-Program 3.1. It contains all entries from continuing and completed Chicken Meat research projects funded by RIRDC as well as projects jointly funded through the Chicken Meat and Egg Industry programs. This program aims to support increased profitability and sustainability in the chicken meat industry through improvements in efficiency, product quality and market size and through the adoption of enlightened management practices. This report is the newest addition to our extensive catalogue of almost 400 research reports, videos and CD-Roms of projects supported by RIRDC. Please contact us for the latest publications catalogue or view it on our website. Peter Core Managing Director Rural Industries Research and Development Corporation

iv

v

Contents

3.1 CHICKEN MEAT COMPLETED PROJECTS

PROJECT

No PROJECT TITLE RESEARCHER PHONE ORGANISATION PAGE

No ACM-2A Nutrient analysis of Australian chicken Dr J Fairbrother 02 9929 4077 Australian Chicken Meat Federation 1 DAN-158A Infectious proventriculitis and stunting syndrome of

broiler chickens Dr R Reece 02 4640 6327 NSW Agriculture 1

DAV-120A The effect of Salmonella Sofia on intestinal infection with other salmonellae in chickens

Dr C Wilks and Ms P Young 03 9217 4200 Department of Natural Resources and Environment, Victoria

2

CSJ-2A Control of ovarian development and function in meat chicken females

Dr J Downing 02 4655 0600 University of Sydney 3

SGH-5A Managing Structural Change in the Australian Poultry Industry

S G Heilbron and J T Larkin 03 9249 9542 S G Heilbron Pty Ltd 4

UM-43A Scoping studies on infectious causes of immunodepression and transmissible viral proventriculitis in Australian broiler flocks

Dr T Bagust 03 9344 9676 University of Merlbourne 5

UMO-12CM Identification of in vivo expressed antigens of Pasteurella multocida

Prof Ben Adler 03 9905 4815 Monash University 6

UNE-54A Increasing efficiency of len tissue deposition in broiler chickens

Dr M Choct

02 6773 5121 University of New England 7

UNS-11A Odour and ammonia emission from broiler chicken growout farms

02 9385 5452 University of New South Wales 8

US-34A Development of DNA vaccines and techniques for cytokine manipulation for improved mucosal immunity in chickens

Prof A Husband and Dr W Muir

02 93517130 University of Sydney 9

US-38A Broiler feed formulation based on digestible amino acids

A/Prof W Bryden and Dr R Ravindran

02 46 550 658 University of Sydney 10

UTS-2A A maternally-delivered vaccine against coccidiosis in broiler chickens

Dr N Smith 02 9514 4013 University of Technology, Sydney 11

YCH-1A Chicken Meat usage and attitude survey Mr D Ellem, Mr M Steele, Mr Tam Tran

02 9927 0007 Yann Campbell Hoare Wheeler 12

3.1 CHICKEN MEAT RESEARCH IN PROGRESS

PROJECT

No PROJECT TITLE RESEARCHER PHONE ORGANISATION PAGE

No CSA-8A Removal of reticuloendotheliosis virus (REV)

contamination from Fowlpox (FPV) S vaccine and FPV field strains for use as enhanced Fowlpox vaccines in Australia

Dr D Boyle 03 5227 5018 CSIRO Animal Health 13

DAN-40CM On farm comparison of computer controlled tunnel ventilated and naturally ventilated broiler sheds

Ms A Mabey 02 4939 8811 NSW Agriculture 14

DAN-142A Production of distance learning materials for the poultry industry - stage III continued

Mr G Creek 02 6953 0299 NSW Agriculture 14

DAN-171A Infectious proventriculitis and stunting syndrome of broiler chickens

Dr R Reece 02 4640 6309 NSW Agriculture 15

DAQ-245A Risk factors for Campylobacter spp. in Australian broilers

Ms J Miflin 07 3362 9520 Department of Primary Industries (Qld)

16

DAV-147A A welfare audit for the broiler industry Dr J Barnett 03 9742 0433 Department of Natural Resources & Environment

17

DAW-74A The control of big liver and spleen disease (BLS) Dr S Plant 08 9368 3873 Agriculture Western Australia 18 DAW-94A Conditioning and analysis of broiler litter to prevent

fly breeding Dr D Cook 08 9368 3250 Agriculture Western Australia 18

IMVS-1A Molecular basis of benign colonisation of Salmonella Sofia in chickens

Dr M Heuzenroeder 08 8222 3275 Institute of Medical & Veterinary Science

19

RMI-7A Use of avirulent Campylobacter jejuni strains to control poultry-derived campylobacter food poisoning

Dr V Korolik 07 5594 8321 Griffith University 20

SAR-13A Physiological limitations in energy metabolism reduce production efficiency of broilers

Mr B Hughes 08 8303 7788 South Australian Research and Development Institute

21

UMO-21A Candidate vaccine antigens and genes of Pasteurella multocida

Prof B Adler 03 9905 4815; Mob: 0417 368 091

Monash University 22

UNE-53A The "New Season Grains" phenomenon and the role Dr M Choct 02 6772 5121 University of New England 22

vi

3.1 CHICKEN MEAT

RESEARCH IN PROGRESS

PROJECT No

PROJECT TITLE RESEARCHER PHONE ORGANISATION PAGE No

of the endogenous glycanases in grains for their nutritive value in poultry

UNS-10A Defined probiotic preparations for competitive exclusion of enteropathogens from poultry

Dr J Cox 02 9385 5665 University of New South Wales 23

UNS-15A Odour emission from broiler farm litter Mr John Jiang 02 9385 5452; 0419 986 886

University of New South Wales 24

US-35A The development of a model of abnormal bone development in broiler chicken as an aid in the assessment of welfare

A/Prof Wayne Bryden 02 4655 0658 University of Sydney 24

US-44A and US-68A

Manipulation of lean tissue deposition by altering the sensitivity of tissues to insulin; and Postgraduate Scholarship – Ron Newman

A/Prof Wayne Bryden 02 4655 0658 University of Sydney 25

US-55A Relationship of gluten proteins to wheat AME A/Prof Wayne Bryden 02 4655 0658 University of Sydney 26

1

3.1 Chicken Meat Completed Projects

Project Title

Nutrient analysis of Australian chicken

RIRDC Project No.:

ACM-2A

Researcher: Ms Janine Lewis, (Australia New Zealand Food Authority) Organisation: Australian Chicken Meat Federation

PO Box 579 NORTH SYDNEY NSW 2059

Phone: 02 9929 4077 Fax: 02 9925 0627 Email: [email protected] Objective

• To provide up-to-date information on the nutrient composition of current cuts of

Australian chicken, both raw and cooked.

Background:

The publicly available information on the nutrient composition of Australian chicken meat is out-of-date and is not completely comprehensive, new data is required.

Research

A range of chicken cuts currently sold were analysed by the Australian Government Analytical Laboratory for a comprehensive list of nutrients.

Outcomes

Excellent data has been produced and is already being used by a number of poultry companies in their promotional products.

Implications

Industry and the public will now have significantly better information available to them on the nutrient content of commonly used Australian chicken products.

Project Title

Infectious proventriculitis and stunting syndrome of broiler chickens

RIRDC Project No.:

DAN-158A

Researcher: Dr Rod Reece Organisation: NSW Agriculture

Elizabeth Macarthur Agricultural Institute PMB 8 CAMDEN NSW 2570


• To control outbreaks of infectious proventriculitis and stunting syndrome associated

with reduced growth and poor performance of broiler chickens by understanding the pathogenesis, determining the aetiology, developing diagnostic tests and producing an appropriate vaccine.

Background:

Infectious stunting syndromes have been an intermittent and sometimes serious problem in the Australian broiler chicken industry from the early 1980s. In the summer of 1993/94, and thereafter, the form of this infectious stunting syndrome involving proventriculitis occurred in several companies in NSW, Victoria and SA. In affected

2

flocks corrected feed conversion was poor, flocks were uneven, weight for age was reduced and litter deteriorated. Major problems were also encountered due to downgrading at abattoirs and difficulties were experienced in fulfilling market contracts and in forward planning of chick placements onto farms where chickens had to be kept for longer than anticipated in order to attain marketable weights. The clinical and pathological findings in the affected birds were similar to those described overseas for transmissible proventriculitis, the aetiology of which has not been defined. Thus, this disease was of considerable concern to the broiler chicken industry and warranted further studies aimed at providing control strategies based on the results of investigations into the aetiology and pathogenesis of the syndrome.

Research

During 1997-1998, broiler chickens from 56 flocks affected with typical infectious proventriculitis and stunting syndrome were examined. The syndrome was described and differentiated from other diseases with which it could be confused, and samples were collected for histological study, future transmission studies involving experimental chickens, electron-microscopy and possible isolation and/or characterisation of the aetiological agent(s). Three transmission trails were undertaken using intestinal and proventricular homogenates from affected birds as inoculae. In one trial, 100% of chickens showed typical gross and histological lesions at four weeks post-inoculation.

Outcomes

The infectious proventriculitis stunting syndrome was defined in pathological terms and confirmed as being associated with significant production problems in seven companies and in five states. Experimental studies demonstrated that the disease was transmissible and therefore due to some infectious agent, but the putative aetiological agent was not identified, let alone characterised.

Implications

The infectious proventriculitis stunting syndrome seen in Australian broiler flocks is transmissible and therefore due to an infectious agent. Further studies are now underway to identify the causative agent, so that appropriate diagnostic and control strategies for the disease can be developed.

Project Title

The effect of Salmonella Sofia on intestinal infection with other salmonellae in chickens

RIRDC Project No.:

DAV-120A

Researcher: Dr Colin Wilks and Ms Petrina Young Organisation: Dept of Natural Resources and Environment

Victorian Institute of Animal Science 475 Mickleham Road ATTWOOD VIC 3049


• To determine whether or not prior intestinal infection with Salmonella Sofia limits

the colonising ability, on subsequent exposure, of other salmonellae that are pathogenic to humans.

Background:

Infection of commercial broiler chickens in Australia with S Sofia is relatively common. This serovar of salmonella does not appear to be associated with significant disease in chickens nor has it been identified as a major cause of disease in humans. It is possible that an established intestinal infection with S. Sofia limits the ability of other pathogenic species of salmonella to subsequently infect and colonise the intestine. Such an effect

3

may be due to a process described as ‘competitive exclusion’. If S. Sofia is shown to be an effective competitive excluder then there are considerable advantages in exploring ways to use this property to control infection with other salmonella serovars of more health concern without the need to resort to antibiotic or vaccine usage.

Research

In the first stage of the research, strains of Salmonella Sofia and Typhimurium (a pathogenic species) were selected. They were made resistant to specified antibiotics to enable their direct culture and enumeration in the faeces of chickens that had been infected with them. In the second stage, a protocol was developed which reliably established a persistent infection in chickens with S. Sofia in chickens at one day of age and with S. Typhimurium at five days of age. In the third stage, a series of experiments were run in which chickens which had been infected with Sofia at one day of age were then challenged with Typhimurium at five days of age. This enabled a comparison to be made on the ability of Typhimurium to infect chickens that had or had not been infected previously with Sofia.

Outcomes

The appropriate strains were selected and rendered resistant to the required antibiotics. Optimal doses were determined for establishing the infections by oral dosing at one day of age for Sofia and at five days of age for Typhimurium. Work undertaken also demonstrated that chickens could be readily infected by spraying eggs at the point of pipping with a suspension of Sofia. When the effect of prior infection with Sofia on subsequent infection with Typhimurium was tested it was found that no protective effect could be demonstrated. About this time we became aware through the work of a colleague in South Australia that not all strains of Sofia were the same. With his assistance a collection of strains of Sofia was put together and the protective effect of each of these was tested in the model that had been developed. Almost all of the strains provided no detectable protection but one strain, Number 76, persisted for much longer in the infected chickens and clearly inhibited the ability of Typhimurium to become established.

Implications

It appears that with selection of a suitable strain of Sofia, inhibition of infection and persistence of Typhimurium can be affected. This experiment needs to be repeated to confirm the results but there is good reason to be optimistic that under suitable conditions and with suitable strains, that competitive exclusion could provide an alternative to other methods of minimising salmonella infection in chickens.

Project Title

Control of ovarian development and function in meat chicken females

RIRDC Project No.:

CSJ-2A

Researcher: Dr Jeff Downing Organisation: University of Sydney

Department of Animal Science 425 Werombi Road CAMDEN NSW 2570


• To determine whether hexadimethrine (HDM) and/or protamine sulphate could be

safely used to manipulate follicle development in hen

Background:

Broiler breeder hens do not produce as many eggs as laying hens. Earlier studies have suggested that this is because too many follicles develop in the ovary of these hens.

mailto:[email protected]

4

Research

The ability of two compounds to inhibit the stimulatory effect of fibroblast growth factor on ovarian follicle development was investigated. Studies on the safety of these compounds for hens were also undertaken.

Outcomes

One compound investigated was found to enter cells of the ovarian follicle. This demonstrated that the compound could be administered and reach the target cells. Large amounts of this compound were, however, extremely toxic for hens, but small doses appear to have no deleterious effects on hen health. Administration of the compound, at certain delivery rates, had effects on follicle numbers and/or on the egg production of layer hens.

Implications

A compound was identified which was capable of affecting follicular development in the hen. Whether it (or some related compound) can be used to manipulate egg production in broiler breeder hens has yet to be proven.

Project Title

Managing structural change in the Australian poultry industry

RIRDC Project No.:

SGH-5A

Researcher: Mr Selwyn Heilbron and Mr Terry Larkin Organisation: S G Heilbron Pty Ltd

832 High Street, EAST KEW VIC 3102


• To assist the industry in evaluating its performance and readiness for change and to

develop a blueprint for future growth

Background:

The Australian chicken meat industry has an impressive record of growth but it is now facing a new era of challenge and opportunity arising from deregulation, microeconomic reform, international trade challenges and structural change. The industry needs to assess its readiness for change and chart out a blueprint for future growth.

Research

The research applies techniques of business change management supplemented by economic and agribusiness analysis to evaluate performance and to develop a strategy for future development.

Outcomes

Improved competitiveness can substantially improve future growth. The international benchmark – the United States industry – however appears to be driving further ahead. The Australian industry is exhibiting evidence of successful change but more needs to be done. Value chain problems outside the industry’s control, particularly ACCC obstacles, feed costs and labour “on-costs” require policy attention by governments.

Implications

The industry should accelerate its positive attitudes to change and press on with further analysis of international benchmarks and domestic value chain improvement.

5

Project Title

Scoping studies on infectious causes of immunodepression and transmissible viral proventriculitis in Australian broiler flocks

RIRDC Project No.:

UM-43A

Researcher: Dr Trevor J Bagust Organisation: University of Melbourne

Faculty of Veterinary Science Post Office PARKVILLE VIC 3052

Phone: 03 9344 9676 Fax: 03 9344 9675 Email: [email protected] Internet: Objectives

• To define the dynamics of the viral infections which are challenging broiler flocks

during their production cycle, and relating findings to production performance. • To undertake scoping laboratory investigations to enable a clearer focus on the most

likely cause(s) of transmissible viral proventriculitis disease. Background:

In recent years, some Australian broiler flocks have been exhibiting lower growth rates and higher feed conversion ratios than are acceptable by industry standards. The deleterious effects of pathogenic (disease-causing) viruses, either by known or yet-to-be recognised viral agents, has been suspected by industry veterinarians.

Research

Flocks at four broiler production sites across NSW and Quuensland were studied by serological surveillance for evidence of infection by pathogenic viruses. Flocks were tested at two, four and six weeks of age and at kill-out. Findings for each flock were then compared with clinical histories, growth rates and mortalities. In addition, some 2000 serum samples from broiler breeders submitted from commercial companies were tested for evidence of avian leukosis subgroup J (ALV-J) infection. Transmissible viral proventriculitis (TVP) field occurrences that had been positively diagnosed at four field locations were examined virologically and serologically, in collaboration with the Elizabeth MacArthur Animal Institute of NSW Agriculture.

Outcomes

The immunodepressive pathogens, infectious bursal disease virus (IBDV) and chicken anaemia virus (CAV), were detected as challenges to young flocks on all sites. However the levels of maternal protection via antibody derived from parent breeders varied considerably between the sites, and in some cases was probably not sufficient to adequately protect one to three week-old chickens. Infectious bronchitis virus spread was also detected in problem flocks. ALV-J infection appears widespread in broiler parent stocks. TPV disease problems appeared to be most strongly associated with co-infection by an avian entero-like virus which was isolated in these studies and avian Group 1adenovirus. A contributing role for immunodepressive agents may also be occurring in these field cases.

Implications

Industry might need to reappraise control programs for immunodepressive pathogens such as IBDV. Laboratory technology for culture and rapid PCR diagnosis of ALV-J needs to be developed. Further detailed laboratory studies of TPV should be undertaken to determine the roles in the disease of the viruses identified above. TPV is a multifactorial disease syndrome.

6

Project Title

Identification of in vivo expressed antigens of Pasteurella multocida.

RIRDC Project No.:

UMO-12CM

Researcher: Prof Ben Adler Organisation: Monash University

Department of Microbiology CLAYTON, VIC 3168

Phone: 03 9905 4815 Fax: 03 9905 4811 Email: [email protected] Objectives

• To apply genetic techniques to identify potential vaccine antigens of P. multocida

with emphasis on antigens which are expressed only when the bacteria are growing within the host (i.e. in vivo expressed antigens).

• To produce each antigen in purified recombinant form and test its ability to protect chickens from fowl cholera infection.

• To identify P. multocida genes which are involved in pathogenesis (the ability of the bacteria to cause disease) with emphasis on those expressed in vivo.

• To construct mutant P. multocida strains for each such gene and assess their virulence and ability to stimulate protective immunity.

Background:

Infection by Pasteurella multocida causes fowl cholera in poultry, bovine haemorrhagic septicaemia and porcine atrophic rhinitis. It is thus of major economic importance worldwide, but especially in Australia and South East Asia. Despite this, very little is known about its pathogenesis (disease causing ability) or about immunity to infection. This project seeks to apply modern techniques of molecular microbiology to identify bacterial antigens involved in immunity to infection (especially cross immunity among different serotypes) and to identify bacterial virulence genes which might be potential targets for attenuating mutations and thus provide the basis for the construction of live, attenuated vaccines.

Research and Outcomes

A genetic system was developed which allowed the identification of genes which encode antigens or other proteins of P. multocida which are expressed in vivo. A second approach targeted other candidate genes and antigens on the basis of their similarity to those of other bacterial species. This allowed the identification of a panel of potential vaccine antigens which were expressed and purified in recombinant form. At the time of writing three of these are undergoing chicken testing and at least another four are in various stages of cloning, expression or preparation. The construction of genetically defined mutant strains has been delayed by technical difficulties. However, one mutant strain was constructed and a further four putative virulence genes have been identified, cloned and sequenced and the genes disrupted in E. coli. The corresponding P. multocida mutants are currently under construction.

Publications

Eleven scientific papers on P. multocida were published in the project period and ten conference papers were presented. In addition, the work supported here was presented at invited seminars in Australia, Austria, Denmark, France, The Netherlands, Singapore and the USA. Please contact the researcher for details.

7

Project Title

Increasing efficiency of lean tissue deposition in broiler chickens

RIRDC Project No.:

UNE-54A

Researcher: Dr Mingan Choct Organisation: University of New England

ARMIDALE NSW 23510 Phone: 02 6773 5121 Fax: 02 6773 3275 Email: [email protected] Objective

• To increase the efficiency of lean meat growth in broiler chickens through nutritional

manipulation of protein degradation via the insulin axis.

Background:

Genetic selection of broiler chickens over the past 40 years has resulted in extremely rapid growth rate. It has also increased carcass fat content. A combination of organic chromium and a branched-chain amino acid, leucine, and some long chain fatty acids may enhance protein deposition, thereby reducing fatness in broiler chickens.

Research

Two experiments were conducted to examine the effect of graded levels of organic chromium and leucine and four different fat sources on the body composition of broiler chickens.

Outcomes

Chromium picolinate at 0.5ppm significantly (P<0.05) lowered the carcass fat level. Leucine did not interact with chromium to effect lean growth. Chromium had no effect on bird performance. Dietary leucine above the recommended maintenance level (1.2% of the diet) markedly (P<0.001) reduced the breast muscle yield. The addition of fish oil to broiler diets reduced (P<0.05) the abdominal fat pad weights compared to birds on linseed diets. The amount of fat in the diet (2% or 4%) did not affect body composition.

Implications

Provisions could be made for chromium levels and some polyunsaturated fatty acids in practical feed formulations to take advantage of their effects on energy utilisation and carcass fat content.

Publications

Honours thesis entitled “Nutritional Manipulation of Lean Tissue Deposition in Broiler

Chickens” by Adam Naylor, University of New England, Armidale.

8

Project Title

Odour and ammonia emission from broiler chicken growout farms

RIRDC Project No.:

UNS-11A

Researcher: Organisation: University of New South Wales

Odour Research Laboratory Centre for Water and Waste Technology PO Box 1 SYDNEY NSW 2052

Phone: 02 9385 5452 Fax: 02 9313 8624 Email: [email protected] Internet: http://www.odour.civeng.unsw.edu.au Objective

• To quantify odour and ammonia emissions in and adjacent to a selection of typical

broiler farms and to identify and make recommendations on potential remedial measures with a particular focus on operational and management aspects.

Background:

n recent years, local councils have received increasing numbers of odour complaints from residents living in the vicinity of broiler growout farms. Growers have experienced difficulty in obtaining approval to expand existing farms and to establish new farms. Project outcomes should provide a more scientifically informed basis for establishing planning guidelines and the setting of regulatory requirements.

Research

Detailed studies were undertaken on two typical New South Wales broiler farms over four seasons and spot surveys undertaken at a further ten broiler farms in New South Wales and Victoria. The study included measurement of ammonia concentration, odour concentration and ventilation rates in broiler sheds, the investigation of odour intensity relationships for broiler farm odour, the application of Ausplume dispersion modelling to seven of the farms and the conduct of a community survey in the vicinity of one of the farms.

Outcomes

The primary outcomes of the project have been the development of a database of information on odour emission rates, odour intensities and ammonia emissions associated with broiler farms, the development of an improved understanding of odour generation within and dispersion from broiler farms and the development of a set of recommended strategies to assist in the reduction of odour impacts during the chicken growout phase of chicken meat production. Odour dispersion modelling undertaken on the odour emission data collected in the course of the project has established preliminary odour impact criteria for Australian broiler farms.

Implications

Baseline data on odour concentrations within and odour emissions from broiler farms generated by this research is now available for use by industry in assessing, in a quantitative way, its (odour) impacts on the environment and for use in planning applications. The project has paved the way for the development of an accepted protocol for assessing broiler farm odour impacts upon which planning guidelines may in the future be based.

Pulbications

Jiang, J. K. and Sands, J. R., (1997) Odour and ammonia emission at Australian broiler

and growout farms. Proc. Int. Symp. Ammonia and Odour Emissions from Animal Production Facilities. pp 239 -244

9

Project Title

Development of DNA vaccines and techniques for cytokine manipulation for improved mucosal immunity in chickens

RIRDC Project No.:

US-34A

Researcher: Prof Alan Husband and Dr Wendy Muir Organisation: University of Sydney

Department of Veterinary Anatomy and Pathology SYDNEY NSW 2006

Phone: 02 93517130 Fax: 02 93517348 Email: [email protected] Objective

• To improve understanding of the operation of the gut immune system in chickens by

(i) determining the ability of in ovo delivery of antigen and/or immunoregulatory substances to increase IgA antibody at the gut; and (ii) identifying soluble messengers of the immune system (cytokines) involved in controlling levels of IgA production at the gut.

Background:

IgA antibody acts as the first line of defence at the intestinal lumen, which is the site through which a number of pathogens first colonise the chicken. Therefore, increased IgA antibody titres at this site should assist in reducing pathogen infection of the gut. IgA antibody may be increased by immunisation, and in particular by delivery of antigen and adjuvant to the intestinal area. Secondly, extensive studies in mice have shown that particular cytokines very closely control features of the immune response. Further, delivery of the appropriate cytokines as a part of an immunisation strategy can increase IgA antibody titres. Therefore, these studies were designed to identify those avian cytokines which regulate IgA antibody in chicks.

Research

In ovo delivery of antigen with and without immunoenhancer to the 18 day embryo increased total IgA antibody in the first two weeks of life, compared to unimmunsed chickens. However, detailed assessment of the interactions between antigen/immunoenhancer combinations are required as not all substances will increase IgA antibody titres when delivered under this regimen. The cytokine, transforming growth factor-β (TGF-β), is intrinsically involved in regulating IgA antibody production in chickens following vaccination, being present at high levels during the first two days after delivery of an oral booster antigen to previously immunised chickens. A second cytokine, chicken myelomonocytic growth factor, may also regulate IgA antibody in chicks, however it is observed less frequently than TGF-β.

Outcomes

In ovo immunisation of antigen with or without immunoenhancer increases the presence of IgA antibody in chicks during the first two weeks of life. This effect is enhanced when chicks receive an oral booster immunisation of antigen at seven days of age. The cytokine TGF-β acts to direct the immune response in favour of IgA antibody production.

Implications

The levels of IgA antibody in young chicks is improved by the delivery of antigen/immunoenhancer to the 18 day embryo. The generation of IgA antibody at the intestinal site is controlled by the cytokine TGF-β. Ongoing research will evaluate the feasibility of delivering combinations of antigen/immunoenhancer and TGF-β to the embryo, using Embrex Inoveject, to improve levels of IgA antibody posthatch, thereby reducing morbidity and mortality due to enteric pathogens early in life. If successful, this in ovo immunisation strategy could be readily adopted by the industry where in ovo immunisation is already employed.

10

Project Title

Broiler feed formulation based on digestible amino acids

RIRDC Project No.:

US-38A

Researcher: A/Prof Wayne Bryden and Dr Ravi. Ravindran Organisation: University of Sydney

Dept of Animal Science CAMDEN NSW 2570


• To evaluate the formulation of broiler diets on a total amino acid basis vs digestible

amino acid basis, with particular reference to inclusion of cheaper, alternative feed ingredients.

• To examine the utility of the digestible amino acid concept in low-protein diets for broilers.

Background:

There is little doubt that the poultry feed industry requires a better feed formulation system than the one based on total amino acids. With the accumulation of amino acid digestibility data, there is also growing interest in how to use these values in feed formulations. Amino acid digestibility is not the same in all feed ingredients. Some ingredients have lower digestibilities than others. These differences in digestibility can be effectively used as a tool to improve the precision of feed formulations.

Research

A series of growth assays were conducted to demonstrate that differences in digestible amino acid content of feed ingredients result in comparable differences in broiler performance

Outcomes

Formulating diets using digestible amino acid values for meat and bone meal, canola meal and cottonseed meal resulted in superior bird performance than formulation on a total amino acid basis

Implications

Feed formulations based on digestible amino acids will allow the industry to increase the inclusion levels of cheaper, alternative protein sources, to improve the precision of least cost diet formulation and to reduce feed costs. Nitrogen excretion by birds will also be decreased.

Publications

Ravindran, V., Hew, L.I. and Bryden, W.L. (1998) Influence of guanidination on

apparent ileal amino acid digestibility in some protein sources for broilers. Poult. Sci. 77:873-877.

Ravindran, V., Hew, L.I. and Bryden, W.L. (1998) Broiler feed formulations with canola meal based on total or digestible amino acids. Proc. Aust. Poult. Sci. Symp. 10:209.

Bryden, W.L. and Ravindran, V. (1999) Enzyme combinations and nutrient digestibility of wheat for broiler chickens. Proc. Aust. Poult. Sci. Symp. 11:170.

Bryden, W.L., Hew, L.I., Ravindran, V. and Ravindran, G. (1999) Ileal amino acid digestibility for broilers of wheat grown in Australia. Proc. Aust. Poult. Sci. Symp. 11:162.

Ravindran, V. and Bryden, W.L. (1999) Evaluation of broiler diets containing graded levels of cottonseed meal and formulated on the basis of total or digestible amino acids. Proc. Aust. Poult. Sci. Symp. 11:168.

Ravindran, V. and Bryden, W.L. (1999) Evaluation of meat and bone meal in broiler starter diets formulated on the basis of total or digestible amino acids. Proc. Aust. Poult. Sci. Symp. 11:169.

Ravindran, V. and Bryden, W.L. (1999) Amino acid availability in poultry: in vitro and in vivo measurements. Aust. J. Agric. Res. In press.

11

Project Title

A maternally-delivered vaccine against coccidiosis in broiler chickens

RIRDC Project No.:

UTS-2A

Researcher: Dr Nicholas Smith Organisation: Molecular Parasitology Unit

Department of Cell and Molecular Biology University of Technology, Sydney Westbourne Street, GORE HILL, NSW, 2065


• To prove the feasibility of utilising maternal immunity in the control of coccidiosis

by determining whether it is possible to induce the production of maternal antibodies to protect hatchlings against infection with many species of Eimeria by immunisation of breeding hens with a single species of Eimeria specifically. − To confirm that immunisation of hens by oral infection with 10,000 oocysts of

Eimeria maxima results in maternal immunity to E. maxima, E. tenella and E. acervulina;

− To determine which stage of infection is affected by maternal antibodies induced by oral infection of hens with E. maxima.

• To confirm that immunisation of hens by injection of E. maxima gametocyte antigens results in maternal immunity to E. maxima, E. tenella and E. acervulina.

Background:

Coccidiosis is one of the most economically significant diseases of the commercial poultry industry. It is caused by protozoan parasites named Eimeria. Since 1990, considerable research has been devoted to assessing the feasibility of protecting broiler chickens against coccidiosis by vaccinating their parent hens with proteins derived from the parasite; the vaccinated hens produce large quantities of antibodies which are transferred into the egg yolk and are consequently absorbed by the hatchlings. These antibodies inhibit infection. One of the major impediments to the successful application of a subunit vaccine to control coccidiosis is the fact that several different species of Eimeria infect chickens and cause disease. There is, however, evidence that maternal immunisation with selected proteins from the parasite overcomes this obstacle. A subunit vaccine delivered maternally is anticipated to be a very effective and economical way to control coccidiosis in broiler chicken flocks.

Research

Hens were immunised with purified gametocyte proteins of E. maxima or by inoculation with virulent oocysts. The production and transfer of antibodies against Eimeria was monitored in hatchlings. Maternal immunity in hatchlings was determined by infecting hatchlings with various species of Eimeria and measuring how many parasites were able to reproduce in the chickens.

Outcomes

The experiments confirmed that immunisation of hens, either by infection or by injection of parasite proteins, resulted in maternal immunity to E. maxima and E. acervulina. The experiments did not confirm previous observations that this control strategy also induced maternal immunity to E. tenella. The antibody response of the Australian Ross 308 breeder used in these experiments was relatively weak compared to that seen in other breeds of chickens in previous trials and only protected hatchlings against weak or moderate infections, not against very virulent infections; this probably explains why no resistance to the very virulent Australian strain of E. tenella was seen.

Implications

This research has demonstrated that it should be feasible to use maternal immunity as part of a control strategy for coccidiosis in broiler chickens. This principle is being further developed by commercial interests.

12

Project Title

Chicken meat usage & attitude survey

RIRDC Project No.:

YCH-1A

Researcher: David Ellem, Matthew Steele, Tam Tran Organisation: Yann Campbell Hoare Wheeler

357 Military Road, MOSMAN NSW 2088


• To identify consumer perceptions which promote chicken consumption. • To identify consumer perceptions that act as barriers to increased chicken

consumption. • To determine the relative importance of these perceptions. • To establish baseline data for future research.

Background:

Although chicken meat consumption continues to grow, the industry is interested in identifying those consumer perceptions that may act as barriers to the growth in chicken consumption and those consumer perceptions which are promoting growth in chicken consumption so that strategies can be devised to further develop the market for chicken meat.

Research

The Chicken Meat Usage & Attitude study consisted of two separate stages. Stage 1 was a population incidence survey based on 1200 telephone interviews conducted nationally among adults 18 years and over between 27-29th November 1998. Stage 2 was a quantitative study based on 849 telephone interviews conducted in Sydney and Melbourne among main grocery buyers aged 18 years and over. This survey was carried out between 11th December 1998 - 11th January 1999. Data was post-weighted to reflect population incidence figures obtained in Stage 1.

Outcomes

The key perceptions of chicken are overwhelmingly positive. It is seen as an automatic choice for purchase because its popularity with the household, its value for money and its versatility mean it is a food that can be eaten often. Interestingly, the least important perceptions were those related to farming practices, sometimes raised in the media and often inaccurately reported or unfounded, that could give rise to concerns about the safety or health value of chicken meat. About one in four grocery buyers claim to eat “more” chicken compared to twelve months ago; about one in five grocery buyers claim to eat “less” chicken. The most common reasons given for eating “less” chicken than twelve months ago were “change in family numbers/lifestyle” and “change in personal taste”; whilst the most common reasons given for eating “more” chicken than twelve months ago were “health reasons” and “like the taste”. The main reasons given for lack of appeal among grocery buyers who found chicken unappealing are “dislike taste” and “vegetarian”.

Implications

It is recommended that the industry utilise a ‘public relations’ approach towards promoting and sustaining the current strong positive image which grocery buyers have of chicken as a food for main meals. The ‘public relations’ approach is more relevant than an ‘advertising campaign’ approach because the key sources of information used by grocery buyers to obtain information about food, as identified by the study, are newspaper articles, magazine articles and TV news programs.

13

3.1 Chicken Meat

Research in Progress Project Title

Removal of reticuloendotheliosis virus (rev) contamination from fowlpox (fpv) s vaccine and fpv field strains for use as enhanced fowlpox vaccines in Australia

RIRDC Project No.:

CSA-8A

Start Date: 1/11/98 Finish Date: 31/10/99 Researcher: Dr David Boyle Organisation: CSIRO Animal Health

Australian Animal Health Laboratory Private Bag 24 GEELONG VIC 3220


• To develop alternative fowlpox virus (FPV) vaccine strains for use in Australia.

These strains will provide enhanced levels of protection in the face of severe field challenge which is occurring at some locations in Australia. The new FPV vaccines will be of higher immunogenicity than those currently available and will be free of reticuloendotheliosis virus (REV) contamination either as free virus or as provirus integrated into the FPV genome.

Current Progress:

Three fowl pox virus (FPV) strains (isolates made from New South Wales and Victoria and the previously available S vaccine strain) have been selected for development as alternative vaccines. Additional primary isolates from outbreaks in NSW and Queensland have been obtained as a back up to the chosen isolates. Removal of the integrated reticuloendotheliosis virus (REV) genome from the FPV strains is being pursued by two strategies. Ninety-six individual plaques have been picked and cultivated from each of the three chosen strains. These plaques are being screened by hybridisation and PCR analysis for the presence of integrated REV. If plaque isolates are obtained free of most of the REV genome they will be developed further as potential vaccine candidates. The second strategy is to specifically delete the REV sequences from the FPV genome by recombinant DNA techniques. Three independent, twice plaque purified lines have been derived from each of the three chosen strains. The presence of REV in the genome has been confirmed by PCR analysis and these lines are being used as the parent strains for the specific deletion of the REV sequences. First round plaque purified derivatives are currently being cultivated and soon will be tested to determine if the REV sequences have been successfully deleted. Testing in chickens will be undertaken with FPV strains obtained by either of these two strategies.

14

Project Title

On farm comparison of computer controlled tunnel ventilated and naturally ventilated broiler sheds

RIRDC Project No.:

DAN-40CM

Start Date: 1/01/95 Finish Date: 31/7/99 Researcher: Ms Anne Mabey Organisation: NSW Agriculture

C B Alexander Agricultural College ‘Tocal’ PATERSON NSW 2421

Phone: 02 4939 8811 Fax: 02 4938 5549 Objectives

• To compare the performance of two commercial broiler shed designs. The two

designs are: (i) computer controlled, insulated, curtain sided tunnel ventilated sheds; and, (ii) computer controlled, curtain sided, insulated, naturally ventilated sheds.

• To compare the performance of these shed designs on the basis of financial return per square foot of shed space, bird feed conversion ratio, batch mortality rates, bird behaviour and several shed climatic factors (temperature, humidity vs ambient temperature/humidity and daily variations of both).

Current Progress:

The return per bird and feed conversion ratio figures show that the performance of all four sheds (two tunnel ventilated and two naturally ventilated) has been at or above the pool average for the last twelve batches. There appears to be little difference in terms of flock performance between the tunnel ventilated sheds and the naturally ventilated sheds. A preliminary analysis of mortality and weight gain versus the age of the breeder flocks from which the broiler flocks were derived suggests that the age of the breeder flock influences broiler performance. Preliminary examination of results suggests that broiler flocks derived from parent flocks less than 30 weeks of age or greater than 50 weeks of age may not perform as well as chickens from breeder flocks between these ages. Whether chicks from the older hens perform better in the tunnel ventilated sheds has yet to be examined. As reported previously, the tunnel ventilated sheds appear to be easier to manage than the naturally ventilated sheds. This was borne out this summer when a final clear-out of chickens was done on a very warm night. Chickens from the naturally ventilated sheds showed higher mortality in transit to the processing plant.

Project Title

Production of distance learning materials for the poultry industry - stage III continued

RIRDC Project No.:

DAN-142A

Start Date: 1/07/96 Finish Date: 31/07/99 Researcher: Mr Geoff Creek Organisation: NSW Agriculture

Murrumbidgee College of Agriculture PMB YANCO NSW 2703

Phone: 02 6953 0299 Fax: 02 6953 0268 Objectives

• To produce distance education material suitable for managers of chicken meat

enterprises.

15

• To evaluate the distance learning materials • To arrange accreditation for the distance education course "Commercial Meat

Chicken Management"

Current Progress:

It is expected that all units in the external study course for managers and supervisors in the meat chicken industry will be completed and ready for printing by mid-July 1999. This course will be available for delivery to external students in the meat chicken industry before the end of 1999. The nine units of distance learning materials are at the following stages of development: Unit A - Hatchery and Breeder Management - layed out; glossary and assignments to be added. Unit B - Land Use, Housing and Equipment - at printers. Unit C - Health and Welfare - published. Unit D - Feeding Practices - at printers. Unit E - Brooding and Rearing Meat Chickens - published. Unit F - Running the Business I - refereed; layed out; undergoing final edit. Unit G - Running the Business II - complete and refereed; assignment and review questions being modified; yet to be printed. Unit H - Industry Issues - layout underway; undergoing further refereeing. Unit I - Products and Marketing - layout on hold while awaiting further feedback from referees.

Project Title

Infectious proventriculitis and stunting syndrome of broiler chickens

RIRDC Project No.:

DAN-171A

Start Date: 1/07/98 Finish Date: 30/06/01 Researcher: Dr Rod Reece Organisation: NSW Agriculture

Regional Veterinary Laboratory Elizabeth Macarthur Agricultural Institute PMB 8 CAMDEN NSW 2570


• To understand the cause of infectious proventriculitis and stunting and develop

relevant control strategies.

Current Progress:

Progress on the project has been somewhat set back by the considerable involvement of the principal investigator in activities related to diagnosis and control of the virulent Newcastle disease outbreaks which occurred in NSW poultry flocks in late 1998 and early 1999. Nevertheless, several field cases of stunting and poor performance in NSW broiler flocks associated with severe proventriculitis were submitted for investigation. The histology in these cases was similar to that previously described for infectious proventriculitis and stunting syndrome (IPSS). Electron-microscopic examination of affected proventriculii revealed intranuclear, hexagonal, non-enveloped, virus-like particles in alveolar oxynticopeptic cells. These particles were 140 nm in diameter and larger than those reported by Goodwin from the USA (60-70 nm). Two groups of transmission trials were conducted. Proventriculitis was reproduced in these trials (45% in Trial 98/2 room 8; 20% in Trial 99/1 room 7). The inoculated birds in these trials had serological or histopathological evidence of infection with infectious bursal disease virus, infectious bronchitis virus, chicken anaemia virus, reovirus, virulent fowl adenovirus

16

type 8, pancreatic degeneration and enteropathic picornavirus. In addition, a cytopathic avian nephritis virus was isolated from one inoculum by Dr Bagust at the University of Melbourne, along with laboratory evidence being obtained for the presence of avian adenovirus, infectious bronchitis virus (possibly a vaccine strain) and avian nephritis in this field derived material. Histological lesions consistent with avian nephritis virus and positive serology were found in other groups. This indicates that the inoculae contain a number of serious pathogens, some of which may prove difficult to remove. Alternatively, the presence of these other pathogens may be predisposing factors for the development of the full IPSS syndrome.

Project Title

Risk factors for Campylobacter spp. in Australian broilers

RIRDC Project No.:

DAQ-245A

Start Date: 1/07/98 Finish Date: 30/06/01 Researcher: Ms Jeanette Miflin Organisation: Department of Primary Industries (Qld)

Animal Research Institute Locked Mail Bag No 4 MOOROOKA QLD 4105


• To reduce the levels of Campylobacter spp. in Australian broilers by the development

of on-farm HACCP plans that are based on risk factors relevant to Australian conditions.

Current Progress:

The first phase of the project, a cross-sectional study to determine the on-farm prevalence of Campylobacter spp., is almost complete. This survey is based on a formal random sample of all broiler growout operations supplying the three major chicken meat companies in south east Queensland. Fifty six farms are being sampled in the week prior to partial depopulation (30-35 days of age). Ten fresh faecal droppings per shed from every shed are collected and cultured for Campylobacter spp. The study will determine, by means of a questionnaire, the farm management variables that might constitute risk factors for colonisation. The survey indicates that it is possible to provide Campylobacter-free poultry to the abattoir. Testing of 2330 samples to date demonstrates that approximately 50% of farms and 70% of sheds are negative at this age. Campylobacter colonisation may be attributable to such practices as re-use of litter, variation in shed cleaning procedures, or other biosecurity issues including use of footbaths or presence of other animals. The next phase of the project will involve longitudinal studies on selected farms starting at day-old and covering several consecutive production cycles. DNA-based typing methods will be used in an attempt to verify the source(s) of the organisms.

17

Project Title

A welfare audit for the broiler industry

RIRDC Project No.:

DAV-147A

Start Date: 1/07/98 Finish Date: 31/08/99 Researcher: Dr John Barnett Organisation: Department of Natural Resources & Environment

Animal Welfare Centre Victorian Institute of Animal Science Private Bag 7 WERRIBEE VIC 3030


• To provide practical audit documentation for industry to use either independently or

to incorporate into quality assurance programmes for use in welfare assessment that reflects industry's continuing commitment to high standards of animal welfare for all sectors of the broiler industry (breeding, hatching, transport of newly hatched chickens, rearing, growing).

Current Progress:

The first step in this project was the formation of a project management group. Membership was offered to appropriate people on the basis of advice provided by RIRDC, the Victorian Chicken Meat Council and local contacts. The group comprises 16 people and includes researchers, educators, company and industry representatives and welfare representatives (both Government and community based). Draft documentation has been prepared for the following industry sectors: brooding/rearing, layer, hatchery and grower. The format for each sector is (i) audit questions to be completed by yes/no answers; where appropriate, code of practice recommendations and some suggested targets are included (ii) a purpose and rationale for the categories of questions; this puts the questions into the context of relevant codes of practice and explains the importance of various practices from the perspective of ‘good farming practice’ and (iii) various appendices, including recording sheets for growers/producers to demonstrate compliance with the audit process. A pilot test of the grower documentation will commence shortly to obtain additional grower inputs into the audit process. Documentation for the remaining sectors of the broiler industry (transport and slaughter) will be the focus of a new project.

18

Project Title

The control of big liver and spleen disease (BLS)

RIRDC Project No.:

DAW-74A

Start Date: 1/07/96 Finish Date: 30/06/99 Researcher: Dr Sarah Plant Organisation: Agriculture Western Australia

Chemical Services 3 Baron-Hay Court SOUTH PERTH WA 6151


• To reduce the financial losses associated with BLS by the development of appropriate

diagnostic and control measures including vaccination schedules.

Current Progress:

The degenerate PCR primers developed from the amino acid sequencing of purified 16-18 kDa protein of BLS virus were used to obtain sequence data for a 500bp section of the viral genome. Specific PCR primers have been designed which amplified a 490bp product from livers infected with several distinct BLS isolates but not from uninfected livers. The sequence data from all isolates has been similar and showed significant homology with hepatitis E virus. Further sequencing along the genome is in progress to attempt to identify and clone the BLS genome segment that translates to the 16-18 kDa immunodominant protein. Expression of this protein in E coli may provide an efficient alternative for vaccine production. Studies using vaccine prepared from the 16-18k Da BLS protein plus adjuvant were completed in broiler breeder and SPF layer hens. They showed that vaccinated birds given a large virus challenge cleared antigen from tissues significant more rapidly than control birds. A large scale vaccination trial in commercial boiler breeder hens is underway at Medina Research Station. Vaccinated groups, by two weeks after challenge, had BLS antigenaemia rates of 0-3% compared with unvaccinated controls (28%) indicating the vaccine had provided significant protection.

Project Title

Conditioning and analysis of broiler litter to prevent fly breeding

RIRDC Project No.:

DAW-94A

Start Date: 1/12/98 Finish Date: 30/06/00 Researcher: Dr David Cook Organisation: Agriculture Western Australia

Entomology Section Locked Bag 4 BENTLEY DELIVERY CENTRE WA 6983


• To determine the critical requirements of the conditioning process needed to prevent

fly breeding in poultry litter; • To evaluate the agronomic performance of conditioned poultry litter (CPL) relative to

raw poultry litter and compost in crop production (pre and post-plant); • To network key stakeholder groups to a) provide commercial input into the field

19

research and development of the treatment process, and b) direct communication strategies to ensure industry usage of CPL.

Current Progress:

Poultry litter has been conditioned (turned and watered daily) for up to eight weeks over summer. Samples of conditioned litter from each of three different litter bases (jarrah, pine and sawdust) has been collected and both exposed to flies in the field and analysed for a range of physical and chemical parameters. Strips of (a) raw poultry litter (b) conditioned poultry litter (four to eight weeks of conditioning) with/without two to eight weeks of storage and (c) compost, have been exposed across six horticultural properties and fly eggs/larvae in this material allowed to develop into adult flies under laboratory conditions. Counting and species identification of the adult flies will be complete by August 1999. No adult flies were able to develop in compost. Detailed chemical analyses of poultry litter through the conditioning process and after two to eight weeks of subsequent storage has been undertaken to determine the key indicators of plant fertilizer value of the material and to enable correlations of physico-chemical parameters with levels of fly larval development. Seven agronomic trials using eight week conditioned poultry litter as a preplant and postplant fertiliser in vegetable, turf and strawberry production have been established. Marketable yields from crops grown with either raw poultry litter or conditioned poultry litter, with or without nitrogen fertiliser, have been measured in three crops.

Project Title

Molecular basis of benign colonisation of Salmonella Sofia in chickens

RIRDC Project No.:

IMVS-1A

Start Date: 1/08/97 Finish Date: 30/07/00 Researcher: Dr Michael Heuzenroeder Organisation: Institute of Medical & Veterinary Science

PO Box 14 Rundle Mall ADELAIDE SA 5000


• To continue to offer to industry the conventional and molecular typing service

developed in the course of RIRDC projects. • To evaluate Salmonella Sofia strains that have been characterised genetically (ie

rationally chosen) for their ability to colonise and competitively exclude virulent serovars eg Typhimurium.

• To identify the bacterial factor involved in the efficient colonisation of chickens by S Sofia and to genetically characterise them by DNA sequence analysis.

• A long term aim of the project (outside of the three year time frame of the current project and contingent upon the objectives above being successfully achieved) would be to place the factor characterised above into a non Salmonella organism for competitive exclusion purposes.

Current Progress:

In 1998/99 no significant change in the distribution of Salmonella serovars in chickens occurred. Salmonella II Sofia is still the most commonly isolated serovar from chickens and is still rarely seen in humans. The Australian Salmonella Reference Centre is now offering a phage typing service for S. Virchow together with molecular typing by pulsed field gel electrophoresis (PFGE). Experiments conducted in collaboration with the Victorian Institute of Animal Science have demonstrated that certain Salmonella Sofia strains are better colonisers of chickens

20

than others. High numbers of bacteria could still be isolated from chickens after 36 days post-infection in the case of these strains. It was also demonstrated that certain S. Sofia isolates could persist for similar periods after challenge with S. Typhimurium. At this stage, it is unclear whether S. Sofia reduced the numbers of S. Typhimurium colonising the birds. Further testing is underway to confirm this observation. Fimbriae are bacterial appendages important for colonisation of host animals. The SEF17 (agf) and lpf fimbrial gene sequences have been identified in most S. Sofia. The genes encoding these fimbriae have been cloned and mutagenised to prevent fimbrial synthesis. It is planned to test these mutants in chickens to determine whether these fimbriae are responsible for stable S. Sofia colonisation of chickens.

Project Title

Use of avirulent Campylobacter jejuni strains to control poultry-derived campylobacter food poisoning

RIRDC Project No.:

RMI-7A

Start Date: 1/07/97 Finish Date: 30/06/00 Researcher: Dr Victoria Korolik Organisation: Griffith University

School of Health Sciences, Gold Coast Campus PMB 50 GOLD COAST MAIL CENTRE QLD 4217


• To detect and identify those strains of Campylobacter jejuni that colonise chickens

but do not constitute a disease problem in humans • To establish a typing scheme for campylobacter spp that will be available to

characterise flock isolates • To develop a molecular typing scheme that will distinguish human virulent strains of

campylobacter spp from normal flora animal strains • To develop an inoculation mixture for use in chickens that will constitute avirulent

competitive exclusion strains of campylobacter spp for use in chickens.

Current Progress:

Thermophilic Campylobacter species such as C.jejuni and C.coli are recognised as major causes of acute gastroenteritis in humans following consumption of contaminated foods. C. jejuni and C. coli are widespread in the gastrointestinal tract of food animals, where they are present as normal intestinal flora and do not cause disease. Previous work has shown that C. jejuni strains associated with disease in humans are genetically different from the majority of those strains that colonise chickens and also that campylobacters vary in their ability to colonise the chicken intestinal tract. One of the major objectives of this project is to identify a Campylobacter strain that colonises chickens but is not pathogenic in humans. Such a strain may be able to be used as a ‘bio-replacement’ organism to reduce the occurrence of disease causing campylobacters in chickens destined for human consumption. A selection of Campylobacter strains has been tested for their ability to efficiently colonise chickens and also their ability to invade human cells in tissue culture. It has been demonstrated that C. jejuni strain 331 is highly efficient at colonising chickens. The strain has been extensively tested for its invasive (and thus potentially pathogenic) characteristics using human tissue culture cells and in four independent assays this strain was not invasive. Other potential virulence characteristics of this strain need to be examined, but the lack of invasiveness in human tissue culture indicates that C. jejuni 331 may be a candidate ‘bio-replacement’ organism to minimise occurrence of virulent C. jejuni in chickens.

21

Project Title

Physiological limitations in energy metabolism reduce production efficiency of broilers

RIRDC Project No.:

SAR-13A

Start Date: 31/10/98 Finish Date: 31/03/02 Researcher: Mr Bob Hughes Organisation: South Australian Research and Development Institute

Nutrition Laboratory Pig and Poultry Production Institute, Roseworthy Campus ROSEWORTHY SA 5371


• To develop non-invasive methods for measuring gut function in chickens. • To define the role of gut structure and function in limiting energy metabolism. • To identify the mechanism(s) by which physical and chemical properties of feed

promote sub-optimal digestion of energy. • To develop a clearer understanding of the physiological limitations of digestion

which will under-pin opportunities for development of specific strategies to reduce the cost of production of lean chicken meat.

Current Progress:

Breath analysis is a well-accepted, non-invasive method for diagnosing gastro-intestinal tract dysfunction in humans. Breath tests for specific gut functions are based on measurement of 13CO2 or non-labelled hydrogen and methane in breath samples taken periodically after ingestion of suitable dietary substrates. Preliminary experiments have provided proof of the concept of using breath tests as tools to study gut physiology in broiler chickens. Individual three week old chickens were given 13C-octanoic acid via gelatine capsule or naturally labelled corn via a tube inserted into the oesophagus. Serial breath samples were taken through a simple plastic helmet placed over the head and neck of the chicken for 30-45 seconds. A sample of gas was drawn from the helmet into an evacuated tube which was loaded directly into a mass spectrometer for determination of total CO2 and the relative proportions of 13CO2 and 12 CO2. The patterns of recovery of the stable isotope 13C in breath samples are similar to those seen in humans and other animals, with the possible exception of the rate of release, which is not surprising given the relatively rapid transit of digesta commensurate with the growth rate of broilers. The techniques developed for breath collection can now be applied to the development of specific breath tests to examine energy metabolism in chickens along the lines of those developed for diagnostic purposes in humans.

22

Project Title

Candidate vaccine antigens and genes of Pasteurella multocida

RIRDC Project No.:

UMO-21A

Start Date: 1/12/98 Finish Date: 30/11/00 Researcher: Prof Ben Adler Organisation: Monash University

Dept of Microbiology CLAYTON VIC 3168


• To build upon previous work on the evaluation of the potential of genes of

Pasteurella multocida as candidates for attenuating mutations for the construction of live vaccines.

• To assess the capacity of expressed recombinant antigens to protect against infection in chickens.

• To make firm recommendations with respect to the choice and development against fowl cholera.

Current Progress:

A number of recombinant antigens and target genes, which have been identified as potential candidates for development into new P. multocida vaccines, are currently at various stages of evaluation. The P. multocida Oma87 outer membrane protein which protected mice, failed to protect chickens. However, the homologue of Oma87 in H. influenzae (called d15) is protective and so fragments of Oma87 corresponding to the protective d15 region are currently being prepared. The P. multocida fimbrial subunit protein also did not protect chickens and therefore recombinant whole fimbriae are being cloned and expressed in Pseudomonas. An acapsular mutant of P. multocida B:2 was attenuated in mice; a similar mutant from type A:1 (fowl cholera strain) is therefore under construction. Other cloned antigens (Tbp1, Tbp2, OmpM, OmpX) are presently undergoing expression and purification for immunogenicity testing.

Project Title

The new season grains phenomenon and the role of the endogenous glycanases in grains for their nutritive value in poultry

RIRDC Project No.:

UNE-53A

Start Date: 1/08/96 Finish Date: 1/08/99 Researcher: Dr Mingan Choct Organisation: University of New England

Department of Animal Science ARMIDALE NSW 2351


• To investigate the new season grains phenomenon, in particular the role of

endogenous glycanases (non-starch polysaccharide-degrading enzymes) in cereal grains for their nutritive value in broiler chickens.

Current Progress:

Four samples of the cereal grains, wheat, barley, triticale and oats, were collected at the

23

time of harvest in 1997/1998 and their metabolisable energy (ME) values determined as a measure of their nutritive value in broiler chickens. ME trials were conducted approximately at three-month intervals, with the first one being completed within 30 days of harvest. The results from the 1997/1998 harvest season demonstrated that the post-harvest improvement in ME of cereal grains differed widely, with wheats responding most positively to normal storage. Barleys and oats also responded positively, but the magnitude of increase in ME with storage was smaller compared to wheats (0-0.5MJ for barleys and oats vs 0.7-3.0MJ for wheats). Sorghum and maize, used as controls in the ME assays, did not respond to storage. Three triticale samples (Tahara, Abacus and Madonna) grown in north west NSW had high ME values (>14 MJ/kg DM) at the time of harvest and did not exhibit post-harvest change. One triticale grown in Riverton, South Australia, had a lower ME value (13 MJ/kg DM) and did not respond to storage. The post-harvest improvement in ME usually peaked after three to four months of storage at ambient temperature. However, storage of selected samples at 4oC extended this response time by another three to four months. For wheat samples that had a low-ME value at the time of harvest, the difference between normal storage and low-temperature storage was up to 0.8MJ after twelve months. The post-harvest improvement in the nutritive value of cereals for poultry is probably due to changes in the cell wall structure of the grains, which may in turn be related to the activities of the endogenous enzymes.

Project Title

Defined probiotic preparations for competitive exclusion of enteropathogens from poultry

RIRDC Project No.:

UNS-10A

Start Date: 1/03/97 Finish Date: 31/03/00 Researcher: Dr Julian Cox Organisation: University of New South Wales

Dept of Food Science and Technology SYDNEY NSW 2052


• To develop fully defined microbial consortia which prevent colonisation of meat

chickens with enteric pahtogens, particularly Salmonella, thereby markedly reducing the significance of poultry as a vehicle of transmission for these pathogens.

Current Progress:

Various mechanisms of competitive exclusion (CE) were investigated in one or both of in vitro and in vivo assays, but there was no correlation between the in vitro assay and protective efficacy in day-old chicks. The standard in vivo assay still remains the ideal method of assessing the efficacy of a CE treatment prior to any field application. CE preparations of different source materials, including fresh caecal fluid or faeces obtained from enteropathogen-free adult birds, were evaluated with respect to reduction or prevention of colonisation by Salmonella in day-old broiler chicks. Such preparations are also currently being evaluated against Campylobacter. A highly efficacious, freshly prepared mixture of caecal fluid and mucosal material was developed, but its efficacy deteriorated with frozen storage and batch fermentation. A bank of approximately 200 undefined isolates was collected from the fresh caecal mixture and studies are currently being carried out to develop a fully defined mixture of isolates, which will be equally or more efficacious than the fresh caecal mixture. At present the protective efficacy of PROTEXIN® is also being determined by trialing it

24

against a range of Salmonella and Campylobacter species prevalent in poultry. Project Title

Odour emission from broiler farm litter

RIRDC Project No.:

UNS-15A

Start Date: 1/01/99 Finish Date: 31/08/99 Researcher: Mr John Jiang Organisation: University of New South Wales

Centre for Wastewater Treatment School of Civil Engineering University of New South Wales NSW 2052

Phone: 02 9385 5452; 0419 986 886 Fax: 02 9313 8624 Email: [email protected] Objectives

• To establish the composition of the off-gases generated in and on litter and relate

these to litter conditions including pH, moisture content, total carbon, nitrogen and sulfide concentrations through a typical broiler growout batch cycle.

• To identify litter characteristics and off-gas composition under both aerobic conditions.

Current Progress:

An experimental laboratory scale reactor comprising four columns (500 mm in height and 100 mm in diameter) has been set up in an air-conditioned laboratory room. A sample of litter comprising portions and pads of faeces, feed, water and wood shavings was taken from the litter surface at week eight of a growout cycle on a broiler farm and packed into the columns. Two columns have been continuously supplied with and without moist nitrogen to simulate anaerobic conditions and two columns supplied with and without moist air to simulate aerated (ie mixed aerobic/anaerobic) conditions. Factors characterizing litter conditions, including pH, moisture content, aerobic and anaerobic bacteria counts, and total carbon, nitrogen and sulfide concentrations have been monitored over a period of four weeks. Samples of off-gas have been collected, twice a week, through Tenax tube for GC-MS analysis for odorous compounds, with ammonia and hydrogen sulfide analyzed on site. Preparatory work for the follow on field study has been delayed as a result of the current Newcastle disease outbreak.

Project Title

The development of a model of abnormal bone development in broiler chicken as an aid in the assessment of welfare

RIRDC Project No.:

US-35A

Start Date: 1/05/96 Finish Date: 31/03/00 Researcher: A/Prof Wayne Bryden Organisation: University of Sydney

Dept of Animal Science Werombi Road CAMDEN NSW 2570


• To develop a model of tibial dyschondroplasia (TD) using the mycotoxin

fusarochromanone. • To examine the influence of factors reported to modulate the incidence of disease in

25

this model. Current Progress:

Although the aetiology of tibial dyschondroplasia (TD) has yet to be fully elucidated, it has been demonstrated that genetic factors play a role in the incidence of the disease. The plasma concentrations of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) and its plasma binding protein, and the apparent proportion of free 1,25(OH)2D3 have been demonstrated to differ in strains of commercial broiler chickens known to vary in their susceptibility to TD. It is the ‘free’ rather than the specifically protein-bound 1,25(OH)2D3 which is available for cellular uptake. Hence, in the susceptible birds with a higher proportion of free 1,25(OH)2D3, this metabolite is likely to be cleared quickly by the liver with less being available for normal bone development. These observations are being further assessed in a TD model induced by feeding chickens the Fusarium toxin, fusarochromanone.

Project Title

Manipulation of lean tissue deposition by altering the sensitivity of tissues to insulin; and Postgraduate Scholarship – Ron Newman

RIRDC Project No.:

US-44A and US-68A




• To reduce fat deposition and increase muscle protein synthesis in the broiler by

altering the sensitivity of tissues to the metabolic hormones in lipid and protein metabolism.

Current Progress:

Feeding broilers a diet containing either a source of n-6 polyunsaturated fatty acids (PUFA) or a source of n-3 PUFA resulted in a 50% reduction in abdominal fat pad mass compared to chickens fed a diet containing the saturated fat tallow. Consistent with the decline in fat deposition was an increase in breast muscle mass and an improvement in feed efficiency. The repartitioning of nutrients by PUFA reflects increased insulin stimulated glucose uptake and utilisation by avian muscle.

26

Project Title

Relationship of gluten proteins to wheat AME

RIRDC Project No.:

US-55A




• To characterise the role that wheat storage (gluten) proteins play in determining

wheat starch digestion and to define the immunological properties of these proteins in chickens.

Current Progress:

In wheat grains, starch granules are embedded in a protein matrix and these proteins may reduce starch digestion and the energy value of wheat. The matrix of storage (gluten) protein is not homogenous but is composed of a number of proteins, especially glutenins and gliadins. Studies are continuing to determine the gliadin and glutenin content of various wheats which have differences in protein and metabolisable energy content. In conjunction with these studies, a gluten rich fraction from wheat has been isolated which will be evaluated for antinutritional properties in feeding studies with broilers.

Documents

Chicken Meat - · PDF filePoultry Industry S G Heilbron and J T ... DAN-142A Production of distance learning materials for the ... and in forward planning of chick placements onto