Basic Nutrients Proteins Lipids Carbohydrates Energy Vitamins Minerals Antinutrients/toxins Attractants

Proteins Most expensive feed component Utilization varies—animal vs plant protein Major source of nitrogen in effluents Must be balanced with energy

Protein Requirements Important due to implications in feeding costs and effluents Must be established with small rapidly growing fish Requirements decrease with increasing size of fish

Protein Studies Minimum requirement studies Individual amino acid requirements Feeding regimes--metabolic studies Alternate protein sources--palatibility, attractability

Weight Gain-Protein Requirement % Dietary Protein ** Serrano et al., 1992

Weight gain (g) g digestible protein/kg bw/day Weight Gain--Metabolic Study McGoogan and Gatlin, 1998

Amino Acid Requirements Must be met to ensure maximum weight gain and health Deficiency symptoms—reduced weight gain, amino acid specific symptoms Methionine and lysine usually most limiting Studies involve feeding diets containing graded levels of test amino acid Data usually fitted to regression analysis or broken line method to determine requirement

Lysine Requirement—Red Drum % initial wt

Methionine Requirement—Red Drum % initial wt

Lipids Efficient energy source Essential fatty acids Phospholipids, steroids, prostaglandins Deposition

Lipid Deposition Excessive deposition--inefficient energy utilization Physiological/health concerns—oxidation of membrane lipids Final product quality

Lipid Studies Inclusion level Essential fatty acids Alternate lipid sources

Lipids--Indicators Weight gain Intraperitoneal fat (IPF) ratio Enzymatic/biological indices

% Dietary Lipid Weight Gain--Lipid Requirement % initial wt Williams and Robinson, 1988

Weight Gain--Lipid Study % Dietary Lipid b a ab % initial wt.

IPF Ratio--Lipid Study % Dietary Lipid c b a ab IPF wt. x 100/body wt.

Lipids--Essential Fatty Acids Certain fatty acids necessary for normal growth and health--n-6 and n-3 Important implications for human health Marine lipids high in n-3 fatty acids,

Lipids--Essential Fatty Acids Freshwater fish usually require linoleic (18:3n-3)--chain elongation:channel catfish Marine fish usually require EPA and DHA-- no chain elongation Other fish--tilapia require n-6, eels, chum salmon, carp require mixture n-3 and n-6

Dietary Lipid Sources Source Characteristic Menhaden oilHigh HUFA Corn oilHigh 18:2n-6 Coconut oilHigh 12:0,14:0 Beef tallowHigh 16:0, 18:0 Soy oilHigh 18:1 TricparylinHigh 8:0

Weight Gain--Alternate Lipid Sources MenhadenCoconutCornMCT2MCT1 Dietary Lipid % initial wt. b b a c c

Weight Gain-Sea Grant % initial wt. MenCocoSoyTallowLec14% Men Coco2 Dietary Lipid

MDA levels--Lipid Study % Dietary Lipid b ab a b nmoles/ g liver

Carbohydrates Inexpensive energy source Variable utilization--species dependent Binding agents-extrusion

Weight Gain of Hybrid Striped Bass CHO/Lipid Study 25/1031/7.536/542/2.5 CHO/Lipid Ratio % initial wt. Nematipour et al., 1992

IPF Ratio of Hybrid Striped Bass CHO/Lipid Study 25/1031/7.536/542/2.5 CHO/Lipid Ratio IPF wt. x 100/body wt. Nematipour et al., 1992 ab bc c a

Energy Growth Maintenance Reproduction

Energy Units Joules (J)- the metric measure of energy, the energy expended in accelerating 1 gram by 1 cm/s calorie (cal) - the traditional measure or energy, the amount of energy to raise the temperature of 1 gram of water from 16.5°to 17.5° C; 1000 calories=1 kcal 1 cal=4.184 Joules

Intake energy Digestible Energy Metabolizable Energy Net Energy Recovered Energy Gill/urine excretion Heat increment Digestion/absorption Waste formation Maintenance Activity Excretory loss fibrous materials Growth, Fat deposition, Reproduction Partitioning of Dietary Energy

Energy Advantages of Fish Heat increment lower than birds and mammals--excrete ammonia vs urea/uric acid Maintenance energy lower—do not regulate body temperature Gravity—smaller portion of energy spent for voluntary or resting activity

Energy:Protein Ratios Proper balance for maximum weight gain Low E:P ratio--reduced weight gain High E:P ratio--increased lipid deposition; reduced feed consumption

Weight Gain of Hybrid Striped Bass Energy/Protein Ratio Study 678 Energy/Protein Ratio % initial wt. Nematipour et al., (kcal/g protein) d cd ab a bc

IPF Ratio of Hybrid Striped Bass Energy/Protein Ratio Study 678 Energy/Protein Ratio IPF wt. x 100/body wt. Nematipour et al., (kcal/g protein) a ab b c c c

Feeding Assessment Feed Efficiency Ratio (FER) = wt gain/ wt feed offered x 100 higher numbers better efficiency Feed Conversion Ratio (FCR) = wt feed offered/wt gain lower numbers better efficiency

Feeding Assessment Typical “good” FCR’s for fish range from 1.5 to 1.8 (FER = 66 to 55%) Poultry also good converters, FCR’s of 2 (FER= 50%) Pigs and cattle higher, FCR’s ranging from 6-10 (16 to 10%)

Finishing/Specialty Feeds Another area of little research Could prove important for enhancing final product quality Seasonal feeds to maximize weight gain under different environmental conditions Marketing--high levels of n-3??

Dietary Lipid CoconutSat MenMenCorn14 Men Median Lethal Temperatures C o a b b bc c

Dietary Lipid CoconutSat MenMenCorn14 Men n-3 HUFA Levels-Cold Tolerance g/100g