Aquatic Feed Nutrition

• Principle of aquatic feed nutrition

• Feed and feeding management

Dong-Fang Deng (dengd@uwm.edu)

Objective of Feeding

To provide the nutritional requirements for

• good health & optimum yield

• minimum impairment on the environment

• cost effective operation

What to feed How much to feed What is the most efficient way to feed

How does fish food affect production costs?

Feed conversion ratio (FCR) = Feed fed (g)/Fish weight gain (g)

Feed

Fish Water Quality

Feed Management

Feed accounts for 30-70% cost in aquaculture production

FCR = 1-2

Trout Feed Salmon Feed

Year 1970 2000 1970 2000

Digestible protein (%) 28 41 43 35

Fat (%) 6 25 14 33

FCR 1.95 1 2.45 0.8

What to feed? How much to feedWhat is the most efficient way

to feed

Protein

Vit

amin

s

Nutrient Compositions of Feeds

•25-55% Protein

•5-35% Lipid

•10-50% Carbohydrate

Protein

•Consisting of a polymer of amino acids.•Indispensible amino acids (IDAA): are required from feeding.•Dispensable amino acids (DAA): can be synthesized by fish.

Amino Acids: building blocks of proteins

Indispensible Abbreviation

Arginine Arg

Histidine His

Isoleucine Ile

Leucine Leu

Lysine Lys

Methionine Met

Phenylalanine Phe

Threonine Thr

Tryptophan Trp

Valine Val

Dispensable Abbreviation

Alanine Ala

Asparagine Asn

Aspartate Asp

Cysteine Cys

Glycine Gly

Glutamate Glu

Glutamine Gln

Proline Pro

Serine Ser

Tyrosine Tyr

Common Protein Ingredients

• Fish meal and Fisheries by products

• Animal byproducts (meat and bone meal, poultry by product meal )

• Plant protein (Soybean meal, canola meal, extruded pea seed meal, corn gluten)

• Novel protein: algae, yeast, distillers dry grain with solubles (DDGS), insect protein

Body pool amino acids

Glucose

Dietary Protein

Ammonia & urine Body protein

Physiological needs

Lipid

Catabolism

Catabolism

Functions of Protein

Energy

Carbohydrate

Functions of Carbohydrates

Cheapest energy sources.

Carbohydrate can be converted into fat.

As a binder to support different physical quality of feed pellets and faeces

Function in cell membrane structure and immune system

Carnivores fish: 15-20%Omnivores fish: up to 40-50%

Common Carbohydrate Sources

• Wheat Flour/Starch, Wheat Bran

• Corn Flour/Starch

• Potato Starch

• Rice

• Cassava

Sources Starch Content Granule Size (um)

Maize 69 35-40

Wheat 65-68 22 (2-26)

Potato 73 40

Rice 88 3-8

Different carbohydrates are varied in digestion

due to their different structures

Lipid

Free fatty acid

Cholesterol

Phospholipid

Triglyceride

•Naturally occurring organic compounds

•Insoluble in water

Functions of Lipids

Palatability Essential fatty acids and energy. Biological membranes (phospholipids and sterols). Enzyme cofactors, fat soluble vitamin carriers, and

fatty acid chaperons. Metabolic regulations and immune functions

Lipid level in fish feed: 5-40% High lipid diet is recommended in RAS or high density

culture system

Common Shorthand Common Name Notation Source

Lauric acid 12:0 Coconut, palm

Myristic acid 14:0 Butter, animal fat

Palmitic acid 16:0

Stearic acid 18:0

Oleic acid 18:1(n-9)

Linoleic acid 18:2(n-6)

Linolenic acid 18:3(n-3) Marine oil, linseed oil

EPA 20:5(n-3)

22:5(n-3) Marine fish oil or algae oil

DHA 22:6(n-3)

Animal and vegetable oil

Universal

Adverse Effect of Excess Dietary Lipid on Fish

• Fish Health: high visceral lipid & fatty liver

• Oxidation problem

• Food intake: decreased intake of other nutrients

• Quality of end product (color, texture, storage shelf-life ect)

Vitamins

• Is present in natural foods in trace amounts.

• Must be obtained from the diet.

• Is essential for normal health, growth, and reproduction.

• Result in a specific deficiency disease or syndrome if it is inadequate from a diet.

• Water and fat soluble vitamins

A vitamin is an organic compound which

Vitamin Function Sources

Thiamin B1 Carbohydrate metabolism Plant seeds, animal tissues

Riboflavin B2 Hydrogen transfer Plant seeds, animal tissues

Pyridoxine B6 Protein metabolism Yeast, cereal brans, egg yolk

Pantothenic acid Lipid & carbohydrate metabolism Cereal, yeast, liver, fish

Niacin Hydrogen transfer Green vegetables, yeast, liver

Biotin Carboxylation & decarboxylation Egg York, animal organs, milk

Folic acid Single-carbon metabolism Yeast, green vegetables, fish

CyanocobalaminB12

Red blood cell formation Fish, and animal tissues

Choline Cell membrane component Wheat germ, soybean, heart

Inositol Component of cell membranes Animal tissue, peas, bean

Vitamin C Blood clotting, collagen synthesis Citrus fruits, liver, kidney

Water-soluble Vitaminfunctions as a coenzyme or a cofactor

Fat-soluble Vitamin

Vitamin Function Sources

Vitamin A Epithelial tissue maintenance, vision

Cod liver oil

Vitamin D Bone calcification, parathyroid hormone

Cod liver oil

Vitamin E Biological antioxidant, reproduction

Plant seed oils, corn oil

Vitamin K Blood clotting Alfalfa and green leafy

Minerals

• Are inorganic elements required for tissue formation, osmoregulation and other metabolic activities.

• Macro minerals: calcium (Ca), magnesium (Mg), sodium (Na), potassium (K), phosphorous (P), sulfur (S), and chlorine (Cl).

• Macro minerals constitute 60-80% of all the inorganic elements in the body.

Macro mineral Function

Calcium Bone, regulation, membrane permeability

Phosphorus Bone, muscle

Magnesium Enzyme activity

Sodium Osmotic balance

Potassium Osmotic balance

Chloride Osmotic balance, acid-base balance

Sulfur Sulfur amino acids, structure

Functions of Macro Minerals

Functions of Micro Minerals

Micro mineral Function

Copper Metalloenzymes

Cobalt Vitamin B12

Chromium Carbohydrate metabolism

Iodine Thyroid hormones, growth

Iron Hemoglobin

Manganese Matrix of bone

Molydenum Xanthine oxidase

Selenium Glutathione peroxidase

Zinc Metalloenzymes

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Energy

• Energy metabolism in fish is similar to that in mammals and birds with two notable exceptions:

– fish do not expend energy to maintain a body temperature different from that of their environment.

– the excretion of waste nitrogen(ammonia) requires less energy in fish than it does in land animals. ( Human: urea, bird and reptiles: uric acid)

Largemouth bass spends more energy in growth than Tuna

Factors affect energy need• Species• Water flow rate• Body size• Feeding level• Temperature and salinity

Optimal Feed & Feeding Management for Sustainable Aquaculture

Nutrition

EnvironmentCost

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