Optimizing Tilapia Nutrition: Feeding, Ingredients & Formulations

1. Fish Feed as Nutrition for Fish and Plants Kevin Fitzsimmons, Ph.D. Sec. Tres. American Tilapia Association Past President – World Aquaculture Society Professor, University of Arizona Aquaponics 12 April 2012

2. Contents • Nutrition • Ingredients and Formulations • Manufacture and Preparation • Storage, Handling, and Feeding Methods

3. Nutrition and feeding behaviours • Tilapia are omnivores (eat lots of things) • Especially capable of consuming decaying vegetable matter • Long intestine • Filter feeders (algae, bacteria, plankton) when young • Need protein and balanced nutrition for rapid growth • Maybe more cost effective to settle for moderate growth

4. Feeding strategy • Juvenile fish are especially good at filter feeding phytoplankton. • Many hatcheries utilize greenwater culture • Juveniles also filter feed on small zooplankters (especially crustaceans) • Save money on juvenile feeds by partial nutrition from natural feed in juvenile ponds and tanks

5. Tilapia nutrition decisions • Natural herbivores and detritivores. • Opportunistic feeders grazing on algae and bacteria in production system. • Fry and fingerlings need high protein (50-40%) diet • Growout needs lower protein (32-28%) diet • “Organic” diets may be needed for “organic” buyers • Compare FCR to decide most efficient diet

6. Minimize fish meal in diet • Use more soybean meal • Utilize other grains treated with phytase • Increase use of other by-product meals (meat and bone, blood, feather, poultry by-product, brewers waste, etc.) • Examine other locally available ingredients (rice bran, cassava leaf meal, etc)

9. Tilapia Biology • Long convoluted intestine. • Digests complex organic matter • Fry are filter feeders • Adults are grazers

10. Proteins • Tilapia need balanced set of amino acids. Basic building blocks of proteins (and muscles) • Ten essential amino acids (required) several more are supplemental

11. Lipids • Lipids are basically fats. • Fish need a variety of long chain hydrocarbon fatty acids for proper growth • Tilapia will also bio-accumulate lipids from consumed algae

12. Remember organic chem? • Found in many freshwater and marine algae, canola, walnuts, soybean, and flaxseeds • Essential part of the nutritional requirement of almost all organisms • Important in neural and cardiovascular functions

13. Facts about fatty acids in other farmed fish • Fatty acids can also be elevated in fish depending on feed ingredients • Higher omega-3’s are expensive and will likely require higher price • Tilapia - Moderate in PUFA’s: 0.387 g/100g raw 0.600 g/100g cooked • Tilapia - Moderate omega 3 FA’s: 0.141 g/100g raw 0.220 g/100g cooked Source – USDA- ARS Lab

14. Carbohydrates • Needed for metabolic energy • Carbohydrates are polymers of sugar. • Common ingredients are corn, sorghum, rice • Molasses is mostly sugar and water. Does not supply as much energy as equal mass of lipid (fat)

15. Fiber • Less digestible material to help move material though the intestines. • Helps with micronutrients

16. Vitamins and minerals • Commonly supplied in “premix” • Often available in natural production of ponds. • Not critical for most semi-intensive fish farm operations. • Very critical in intensive systems (cages, raceways)

17. Pigments • Salmon and trout feeds sometimes include ingredients that impart reddish or pink color to the flesh. • Astanxanthin, canthaxanthin and beta-carotene are commonly used. • These may be plant or algae extracts, or chemically derived. • May also use whole algae as ingredient (Spirulina or Dunaliella) • Yes, the same extracts and algae sold in health food stores, (which was not included in the scare stories)

18. Binding agents • Gums, agar, cooked starches, wheat and corn glutens, and other ingredients can be used for binding.

19. Preservatives • Ethoxyquin • Anti-oxidants • Goal is to avoid rancidity, loss of nutrients

20. Attractants • Fish oil, fish meal, and fish solubles are good attractants

21. Ingredients and formulations • Normally need high protein diets for young • 40-50% • Protein requirements drop as fish reach reproductive age. Lipid demand might increase with egg formation. 30-32% • Growout diets only need 25% protein

24. Manufacturing and preparations

25. Pellet mill

26. Compression pellet mill • Feed mixed with water to dough consistency • Moistened feed put into hopper, pushed down to auger screw • Auger forces feed through the die head. • Holes in die determine pellet width • Knife blade cuts pellets to desired length

27. Extruders • Floating feeds • Feed mixes with steam in barrel of extruder • Cooks ingredients, improves palatability • Gelatinizes starches • Steam expansion and auger forces feed out of barrel with rapid expansion. • Traps air in pellet, allows to float

28. Meat grinders and pasta mills

31. Bioflocs • Deliberate culture of high density of phytoplankton and bacteria

32. Storage • Always keep feed as dry and cool as possible • Avoids spoilage and rancidity of fats in diet • Bags should be on pallets, off floor to allow air to circulate and slow pests (mice, rats, roaches, ants, from getting to bags • Large amount can be stored in bulk in silos.

33. Handling • Reduce rough handling • Crushed pellets form fines which are not consumed by fish. • Fed by hand, blower, belts

34. Conclusions • Tilapia are omnivores • But eating anything will not make you grow fast and strong • Tilapia need balanced nutrition for rapid growth just like human children