Nutritional Diseases in Shrimp

P.M Dunukearachchi (VS/08/124)S.Sukeerthan (VS/08/118)H.K.Isuru (VS/09/127)

Overview

• Nutritional requirements of shrimp

• Proteins and amino acids

• Lipids (Fats, oils)

• Carbohydrate

• Ash and minerals

• Vitamins

• Nutritional diseases

Nutritional requirements

Nutrients

Proteins and amino acids

Lipids (Fats,oils)

CarbohydrateAsh and minerals

Vitamins

Proteins and Amino acids

An expensive component of the shrimp feed Need for formation of muscles, hormones and

enzymes Shrimp require 10 essential amino acids (EAA):

1. Arginine2. Methionine3. Valine4. Threonine5. Isoleucine

6. Lysine7. Leucine8. Histidine9. Phenylalanine10. Tryptophan

first limiting amino acids

of commercial shrimp feed

formulae

Lipids Essential for growth ,synthesis of cellular and subcellularmembranes and metabolic energy (ATP)

The dietary lipids required by penaeids can be categorized into 2classes

1. neutral lipids –i. essential fatty acids - shrimp require 4 essential fatty acids (EFA)

a. linoleic (18:2n–6, LOA)b. linolenic (18:3n–3, LNA)c. eicosapentaenoic (20:5n–3, EPA)d. docosahexaenoic (22:6n–3, DHA)

ii. sterolsiii. Phospholipids - Phospholipids (lecithin) have a growth-promoting effect

in shrimp

2. Carotenoids-Eg. Astaxanthin (responsible for the colour)

greater growth promoting effect

Carbohydrate

provide metabolic energy (ATP)

Important for synthesis of RNA and DNA, mucopolysaccharide

shrimp utilize complex starches like cornstarch better than glucose

Carbohydrates reduce (“spare”) the use of protein, allowing a lower optimal protein level

Chitin - enhanced growth , formation of exoskeleton

Ash and Minerals Important for

skeletal structures Maintaining osmotic pressure Conduction of nerve impulses and muscle contraction Maintenance of acid-base equilibrium Synthesis of enzymes, vitamins, hormones, respiratory pigments, cofactors in

metabolism, catalysts and enzyme activators.

Shrimp can assimilate some of their minerals directly from the water. - Eg: Ca

Macronutrients for shrimp nutrition Ca, P, Mg, K, Cl, S and Na Phosphorus is the most expensive mineral supplement in aquatic feeds. Unconsumed phosphorus leads to nutrient loading of culture systems and

aquaculture effluents. A high percentage of the P in feed grains forms phytic acid which is an

antinutritional factor

Micronutrients for shrimp nutrition Fe, Zn, Cu, Mn, Ni, Co, Mo, Se, Cr, I, Fl, Sn, si, As

Vitamins

Water soluble Vitamins Fat soluble vitamins

thiamine (B1)Riboflavin (B2)Niacin (B3)Pyridoxine (B6)Pantothenic acid (B5)FolateCyanocobalamin (BI2)BiotinCholinemyoinositol (inositol) vitamin C (ascorbic acid)

Vitamin AVitamin DVitamin E (tocopherol)Vitamin K

diets deficient in Vit C, biotin, folic acid, niacin, thiamine and a–tocopherol

poor appetite and cause histopathological changes in shrimp digestive gland cells

poor feed conversion efficiency

result in reduced shrimp growth

Feeding methods

Natural production formulated (compound) aquafeeds

•Stimulating natural production in a pond through fertilization.

•Low cost

•A complete feed is formulated (pellet ) whichprovides all required nutrients in the proper proportions.

•Consider of rapid weight gain, high feed efficiency and shrimp health and quality

•High cost

Nutritional Diseases

1. Soft Shell Syndrome

2. Blue Disease/ Pigment Deficiency Syndrome

3. Red Disease

4. Cramp Tail Syndrome

1)Soft Shell Syndrome

Clinical signs• Shell is thin, persistently soft for several weeks

• Dark and wrinkled

• weakness

• grow slowly, and eventually die.

Causatve agents• Pesticide contamination

• Poor pond water and soil condition

• Use of rancid or low-quality feeds

• Nutritional deficiency-lack of supplementary feeding in ponds with relatively

high stocking densities (Ca and P)

Prevention and treatment

Feed adequately and good-quality feeds.

Flush ponds thoroughly

Maintain the quality of pond water and soil

Provide supplementary feed

2)Blue Disease or Pigment Deficiency Syndrome(PDS)Also known as

• sky blue shrimp disease

• blue-shell syndrome

Caused by low level of carotenoid astaxanthin in feed.

Astaxanthin is the predominant carotenoid in penaeids

Astaxanthin improves colouration, enhances biological functions and improves survival, growth and stress resistance in penaeidshrimp

Treatment

• Natural carotenoids sources -dried Spirulina ,

-carotenoid extracted from Dunaliella

3)Red disease(Aflatoxin poisoning)

Caused by aflatoxin poisoning

Aspergillus sp. is a common contaminant in shrimp feeds and leads to aflatoxin in the food.

This causes red disease or red discolouration.

The condition leads to gradual mortalities and losses of up to 98% in three months.

Gross signs - cession of feeding

- dramatic slowing of growth

- leading to lethargy and weakness.

-The shrimp die rapidly if lifted out of the water.

-Shrimp gather in shallow water at the pond periphery.

-body color change into yellow and then to red,

- The fecal matter will appear red.

-Increased fluid in the cephalothorax ,

Prevention

-Use fresh, recently manufactured feeds.

-Store feeds properly in well-ventilated and cool rooms (preferably at 10–20 oC or lower)

4)Cramp Tail Syndrome (CMS)

• nutrition-related disease

• also called as cramped–muscle syndrome (CMS).

• CTS appears to be caused by one or

more of the following conditions:

• high temperature

• Vibriosis

• mineral imbalances

• toxins in the water.

reduced dietary and/or environmental potassium (relative to the cations Ca, Na and Mg)

• http://www.fao.org/fishery/affris/species-profiles/indian-white-prawn/nutritional-deficiencies/en/

References

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