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

Contents F Nutrition F Ingredients and Formulations F Manufacture and Preparation F Storage, Handling, and Feeding Methods

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Preservatives F Ethoxyquin F Anti-oxidants F Goal is to avoid rancidity, loss of nutrients

Attractants F Fish oil, fish meal, and fish solubles are good attractants

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

Manufacturing and preparations

Pellet mill

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

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

Meat grinders and pasta mills

Bioflocs F Deliberate culture of high density of phytoplankton and bacteria

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

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

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