Download Fish Feed as Nutrition

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  Nutrition  Ingredients

and Formulations  Manufacture and Preparation  Storage, Handling, and Feeding Methods

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

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

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

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 byproduct, brewers waste, etc.)  Examine other locally available ingredients (rice bran, cassava leaf meal, etc)

Tilapia Biology  Long

convoluted intestine.  Digests complex organic matter  Fry are filter feeders  Adults are grazers

Proteins  Tilapia

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

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

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

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 

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)

Fiber  Less

digestible material to help move material though the intestines.  Helps with micronutrients

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)

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) 

Binding agents  Gums,

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

Preservatives  Ethoxyquin  Anti-oxidants

 Goal

is to avoid rancidity, loss of nutrients

Attractants  Fish

oil, fish meal, and fish solubles are good attractants

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

Manufacturing and preparations

Pellet mill

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

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

Meat grinders and pasta mills

Bioflocs  Deliberate

culture of high density of phytoplankton and bacteria

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.

Handling  Reduce

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

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