Fish Nutrition

Fish Nutrition Fish Feed LaDon Swann Illinois-Indiana Sea Grant Program Purdue University and the University of Illinois Cooperative Extension Services Objectives • Introduction • Summarize key points in digestion • Energy flow in fish • Carbohydrates • Protein requirements and utilization Dress Out Percentages and Carcass Characteristics of Various Food Animals. Characteristic of carcass Source Dress Out (%) 60 61 72 72 Refuse (%) 14 15 21 30 Lean (%) 81 60 54 65 Fat (%) 5 25 26 9 Food Energy (kcal/100 g of edible tissue) 112 147 147 115 Channel Catfish Beef Pork Chicken Nutritional Comparisons of Various Proteins 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. • Most fish can’t synthesize ascorbic acid. Fish Diversity • Because there are so many fish species, extreme variation in fish digestive systems exist among the families. 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 Digestive Secretions • Histamine or cerulein are secreted in stomach instead of gastrin • Chitinase activity has been found in some fish. Fish Versus Warm Blooded Animals • Fish require less energy for protein synthesis. – catfish, 0.84 g wt/g diet – chickens, 0.48 g wt/g diet • Reason is better assimilate high protein diets. • Lower energy cost for protein gain. – fish 47 g/Mkcal ME – chicken 23 g/Mkcal ME • However, protein fed to protein gain is similar. Utilization of Feed and Dietary Protein and Energy by Fish, Chicken and Cattle. Feed Composition P (%) Energy (kcal ME/g) 2.7 2.8 2.6 ME-protein ratio (kcal/g) 8.5 16 24 Wt. Gain/ g of diet 0.84 0.48 0.13 Efficiency Protein gain/g protein consumed 0.36 0.33 0.15 Protein gain/ Mkcal ME consumed (g) 47 23 6 Animal Channel Catfish Broiler Chicken Beef Cattle 32 18 11 Bioenergetics • Similar to other animals except: IE - (FE - UI - ZI) % ME = Food Energy – ZI ( energy loss through gills) – 85% of nitrogenous wastes pass through gills Fate of Nitrogen and Phosphorus in Feed Retained 30% N 32% P Food 100% N 100% P Solids 13% N 60-90% P Effluent 70% N 68% P Dissolved 87% N 10-40% P Fish Have Lower Maintenance Requirement • Lower ME for maintenance – RBT • ME = 4.41W0.63 – Mammals • ME = 70.4W0.75 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. – ? ATP / N in Ammonia – 4 ATP / 2 N in Urea – 10 ATP/4 N in Uric acid Why Lower Energy Requirement? • Don’t have to maintain body temperature (HI m) • Less energy to maintain position • Lose less energy in protein catabolism and excretion of nitrogen. 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. 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 Protein and Digestible Energy (DE) Requirements by Various Sizes of Channel Catfish for Maximum Protein Synthesis. Size (g) Protein (g/100 g fish /day) DE (kcal/100 g fish/day) DE/Protein ratio (kcal/g) 3 10 56 198 266 1.64 1.11 0.79 0.52 0.43 16.8 11.4 9.0 6.1 5.0 10.2 10.3 11.4 11.7 11.6 Purina Catfish Chow FR Guaranteed Analysis Crude protein not less than Crude fat not less than Crude fiber not more than Ingredients Soybean meal, ground yellow corn, fish meal, brewers' dried yeast, wheat middlings, animal fat preserved with BHA, vitamin A supplement, vitamin B supplement, D-activated animal sterol (source of vitamin D ), DL-methionine, calcium pantothenate, folic acid, niacin supplement, riboflavin supplement, menadione sodium bisulfite (source of vitamin K activity), ascorbic acid, salt, calcium carbonate, ferrous carbonate, manganous oxide, calcium iodate, copper sulfate, cobalt carbonate, zinc sulfate. 32.0% 3.5% 7.0% Feed Formulation • • • • • Cost of ingredients Nutrient content of ingredients Nutrient requirements Nutrient availability Min.-Max. restrictions of ingredients Catfish Diet With Fishmeal • • • • • • • • • • Menhaden fishmeal Soybean meal (48% P) Corn (ground) Rice bran or wheat Dicalcium phosphate Organic binder Fat (sprayed) Trace minerals Vitamin mix Ascorbic acid 8.0 48.2 29.2 10.0 1.0 1.5 0.05 0.05 0.05 0.038