fish feed as nutrition for fish and plants kevin fitzsimmons, ph.d. sec. tres. american tilapia...

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

Aquaponics12 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 decisionsNatural herbivores and detritivores. Opportunistic feeders grazing on algae and

bacteria in production system.Fry and fingerlings need high protein

(50-40%) dietGrowout needs lower protein (32-28%) diet“Organic” diets may be needed for “organic”

buyersCompare 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 by-product, brewers waste, etc.)

Examine other locally available ingredients (rice bran, cassava leaf meal, etc)

Long convoluted intestine.Digests complex organic matterFry are filter feedersAdults are grazers

Tilapia Biology

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 raw0.220 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