Fish Nutrition Flashcards
How much of production cost does nutrition of fish make up?
40-50% production cost
What are the nutritional requirements of fish?
- Proteins
- Lipids
- Energy
- Minerals & Vitamins
What is the major organic material in fish tissue?
Protein (in fish tissue 60-70% of fish dry weight)
What are the essential amino acids?
Methionine, lysine, arginine, threonine, tryptophan, histidine, isoleucine, leucine, valine & phenylalanine
What are the limiting amino acids in fish diets?
Methionine and lysine
What are lipids?
High energy nutrients. Transporters of fat soluble Vitamins. Important component of cellular membrane.
What provides essential fatty acids to the diet?
Lipids
What are the max % of lipids in a fish diet
up to 15%
What are the most economical source of energy in fish diets?
Carbohydrates (although not essential - they reduce cost of feed and have good binding activity for food manufacture)
Carbohydrate can comprise what % of the fish diet?
up to 25% DM.
Careful with fibre - handle up to 80% fibre. any higher, unable to absorb nutrients
T/F: Fish have a small requirement of energy compared to poultry and mammals
True.
No energy expenditure converting ammonia, no energy expenditure for maintenance of body temp, & their body density is close to water density, low energy expenditure on movement
T/F: Fish can not synthesise vitamins.
True.
Why is Vit C important in a fish diet?
Formation of collagen, bone repair and bone matrix.
Why is Vit E important in the fish diet?
Protects membranes, important to protect structure of cell.
What minerals are important for osmoregulation, bone integrity and bone formation?
Macrominerals: Ca, P, K, Na, Cl, Mg
What minerals are important for enzymes of the fish?
Microminerals: (trace elements) Cu, Fe, Se, Mn, Cr, Co, Zn
What does a trypsin inhibiter do?
binds to enzymes, fish are unable to use it.
How do you formulate a fish feed?
Least cost formulation using linear programming.
What information is needed to formulate a fish diet?
- Nutrient Requirements
- Bioavailable nutrient and energy content
- min and max restrictions of feed concentration of ingredients
- Cost of ingredients
What are the 2 types of fish feed?
- Extruded, (floating) pellets
2. Sinking (pressure-pelleted) pellets
What are more expensive, extruded or pressure-pelleted feed?
Extruded pellets (floating) more expensive.
What is the feed conversion rate of salmon compared to other terrestrial animals?
1.2 : 1 - almost perfectly,
not may animals can you feed 1 kg of feed and get 1 kg of product.
Compare to:
Cattle 8 : 1
Pigs 3.5 : 1
Poultry 2 : 1
