nutritional diseases in shrimps
TRANSCRIPT
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