1	Fish Nutrition and Feeding LaDon Swann Mississippi-Alabama Sea Grant Consortium Auburn University
2	Carcass Characteristics of Various Food Animals
3	Nutritional Comparisons of Various Proteins
4	Nutrient Requirements Energy requirements are lower for fish. Fish require some lipids such as omega-3’s that warm-blooded animals do not. Fish can absorb some minerals from water through the gills. Most fish can’t synthesize ascorbic acid (Vitamin C).
5	Fish Diversity Because there are so many fish species, extreme variation in fish digestive systems exist among the families.
6	Types of GI Tract Herbivores small stomachs and long intestine tilapia carp (stomach is 3X body length) Omnivores moderate size stomach and intestine catfish Carnivores large stomach and short intestine trout striped bass
7	Terms Bioenergetics: Study of the balance between energy intake in the form of food and the energy utilization by animals 1 Calorie: energy required to raise 1 g of water 1 C Kilocalorie (kcal): 1,000 calories Mega Kilocalorie: 10,000 calories
8	More Terms Intake Energy (IE): gross energy content of food source Digestible Energy (DI): difference between gross energy and energy available to animals Fecal Energy (FE): energy lost through feces Urine Energy (UE): energy lost through urine Gill Energy (ZI): energy lost through the gills
9	Even More Terms Metabolizable Energy (ME): difference between DE and energy lost through the FE + UE + ZI Heat Increment (HI): rise in energy expenditure associated with the assimilation of ingested food Maintenance Energy: voluntary activity plus basal metabolism Feeds are based on satisfying maintenance energy PLUS enough nutrition for growth
10	Gross Energy Values Carbohydrates (Glucose) 3.77 kcal/g Proteins (Casein) 5.84 kcal/g Fat (Soybean oil) 9.28 kcal/g
11	Digestible Energy
12	Conversion Efficiency Fish require less energy for protein synthesis. catfish, 0.84 g gain/g food consumed chickens, 0.48 g gain/g food consumed Beef, 0.13 g gain/g food consumed Fish are better at assimilating high protein diets. Fish poorly utilize carbohydrates for energy.
13	Conversion Efficiency Lower energy cost for protein gain Fish 47 g/MKcal ME Chicken 23 g/MKcal ME Beef 6 g/MKcal ME Protein fed to protein gain is similar among fish, birds, and mammals Fish, 0.36 g protein gain/g protein fed Chicken, 0.33 g protein gain/g protein fed Beef, 0.15 g protein gain/g protein fed
14	Fate of Nitrogen and Phosphorus in Feed
15	Comparison of Feed and Dietary Protein and Energy Among Common Livestock
16	Bioenergetics Digestible Energy (DE) Metabolizable Energy (ME) Approximately 85% of nitrogenous wastes pass through gills
17	Heat Increment Heat Increment (HI) of ME is 3-5% in fish vs. up to 30% in mammals. Lower HI is due to the ammonia excretion rather than urea or uric acid. 1 ATP / N in Ammonia 4 ATP / molecule of Urea (2 Nitrogen) 10 ATP/4 N in Uric acid
18	Fish Have Lower Maintenance Requirement Lower Maintenance Energy Rainbow Trout Maintenance Energy = 57kcal/kg bwt to the 0.63 power Mammals Maintenance Energy = 70-83 kcal/kg bwt to the 0.75 power
19	Why Lower Energy Requirement? Don’t have to maintain body temperature (HI) Less energy to maintain position Lose less energy in protein catabolism and excretion of nitrogen
20	Carbohydrates Fish have poor control over glucose levels. Following glucose ingestion, blood glucose levels rise rapidly, but may take hours to decrease. Turnover of glucose in trout is 10X slower than in rats.
21	Proteins Requirements Fingerlings require higher protein than finished fish. 3 g cc (27%) required 4X more than 250 g cc (38%) based on a diet low in energy high energy diet: consumption decreased and 27% wasn’t enough
22	Protein and Digestible Energy Requirements by Sizes of Channel Catfish for Protein Synthesis
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24	Feed Formulation Cost of ingredients Nutrient content of ingredients Nutrient requirements Nutrient availability Min.-Max. restrictions of ingredients
25	Typical Catfish Diet Containing Fishmeal Menhaden fishmeal 8.0 Soybean meal (48% P) 48.2 Corn (ground) 29.2 Rice bran or wheat 10.0 Dicalcium phosphate 1.0 Organic binder 1.5 Fat (sprayed) 0.05 Trace minerals 0.05 Vitamin mix 0.05 Ascorbic acid 0.038
26	Types of Fish Feed Live Algae Zooplankton By-catch/trash fish Formulated Floating Sinking Mixed
27	Feeding Rates Animals must be fed often enough to satisfy maintenance requirements plus planned growth. Feeding methods Percent Body Weight Percent to feed: range from 1-10% per day Growth Rate Biomass to feed Satiation Feeding Feed as much as the animals will eat in 15-30 minutes
28	Feeding Frequency Types of GI Tracts Herbivores => Omnivores => Carnivores Size of Animal Larvae => Juveniles => Adults => Broodstock Frequency 1-10 times per day