Fish Nutrition, The Basics What We Put in our Fish and Why

Paul A. Curtis, AquaSolver LLC

2255 Seaquest Trail, Escondido, CA, 92029 760-518-8170, www.aquasolver.com

For The: San Diego Tropical Fish Society

August 10, 2014

Why is Nutrition Important

• Hardiness • Growth • Normal Development, WSB Juvenile • Gamete Quality, WSB Brood • Disease Resistance, β-Glucans • Life and Death During Development

What We Feed

• Dry Prepared Diets • Flake, Pellets, Home Made

What We Feed

• Live Feeds • Rotifers, Artemia, Copepods

What We Feed

• Frozen Thawed feeds • Sardines, Mackerel, Squid, Shrimp, Brine Shrimp

Live Foods

• Mostly used in larval rearing • Larvae will eat a dry diet buy not

metabolized • What do live food provide

• Nutrition • Gut enzymes • Gut bacteria

• What live foods used by you?

Types of Live Foods

• Paramecia • Rotifers, 225µm • Brine Shrimp, 450 µm • Moina • Daphnia • Copepods (predacious?)

Paramecium

Rotifer

Brine Shrimp Nauplii

Brine Shrimp Cyst Harvest

Moina and Daphnia

Live Food Enrichment

• Why Enrich? • Live foods can be nutrient limiting • Bolster nutrient value of feed, HUFA’s • Life or Death to marine larvae !

• Enrich With What? • Fats, Proteins and Vitamins • Many commercial products

Brine Shrimp Hatch and Enrichment Procedure

• Hatch 24 hrs at 28ºC and 20-30 ppt • 12 hours after hatch begin feeding and can

start to enrich • Some “Directions” have enrichment after

hatch, no-no

Ads and Disads of Live Feeds

• Ads. • Fish like them • Necessary • Can enrich to suit

• Disads. • Expensive • Labor intensive • Can be nutrient limiting • Can be unreliable

Frozen Thawed Foods

• Use Sardines, Squid, Anchovies, Mackerel • Can be deficient in vitamins due to freezing

damage degradation • Can supplement with tablets or other

supplements • Hubbs solution! Injections.

Prepared Diet Production Methods and Feeding

• Types of Production Methods • Steam Pelleted • Extruded • Expanded • Flaked • Other, gelatin, sausage etc.

Steam Pelleting

• Made With Steam (100° to 180° for 35 sec) and Little Pressure

• Binders make ingredients stick together • One of oldest methods of pelleting • Grinding and blending of ingredients • Forced through a die after heating • Pellets cut to length • Blown dry to 8% - 10% moisture

Steam Pelleting Ads

• Less loss of vitamins and other nutrients • Low energy to make • Initial less cost • Smaller mills available for on site

manufacture

Steam Pelleting Disads.

• Less digestible diets • Large amount of fines • Sinking feeds only • Lower feed conversion • Large minimum pellet size (2.4 mm) • Most fat is 20% in diet • Not as durable in warm water

Extruded Diets

• High Pressure and Heat (300°) Applied • Mash placed an barrel of machine and water added • High heat, pressure and friction applied • Starch gelatinized as binder • Forced through die with less pressure on other side

so expands • Air introduced to control buoyancy • Moisture 10-15% so dried to 10% • Screened to remove fines and fat added to reduce

dust and increase fat level

Extruded Diets Ads.• Expansion controlled so buoyancy controlled • Can have fat levels higher than 20% • High temps increase nutrient availability and

increases feed conversions • Better digestibility less waste • Carbohydrate is binder so no fillers needed • Structural integrity allows for smaller pellet size • No fines, durable pellet and uniform size • No sharp edges

Extruded Diets Disads.• Degradation of vitamins, medications and other

nutrients can be high • Higher manufacturing costs • Cost of shipping more as pellet density is less

Flaked Feeds

• Mostly aquarium feeds • Very finely crushed and made into slurry • Made into thin film on screen, baked and

made into flakes • Formulations often quite different than

commercial fish diets

What is Important for Proper Nutrition

• Protein • Fat • Carbohydrate • Ash • Vitamins • Minerals • Moisture • Energy

Tested with Proximate Analysis and is on label.

Bomb Calorimeter

Bomb Calorimeter

Drying Oven

Energy

• All fish require base energy content • All fat, protein and carbohydrates have

energy and varies with digestibility of ingredient

• Energy needed for digestion • Fish have variable use for different

ingredients, eg. Cellulose vs fish protein

Protein

• Most expensive component • Building Blocks for growth, Amino Acids • Key Ingredient in Diets • Affect palatability and Performance • Quality and Quantity Important

• Plant and Animal meals

• Usually included at 25%-50% • ~22 amino acids and 10 are Essential

Essential Amino Acids

• Arginine • Histidine • Isoleucine • Leucine • Lysine

• Methionine (Cystine) • Phenyalanine (Tyrosine) • Threonine • Tryptophane • Valine

Can’t Be Synthesized, Must get from diet

Deficiencies of Essentials

• Methionine • Cataracts

• Tryptophane • Scoliosis, Fin erosion

• Lysine • Fin Erosion, Mortality

Where Do We Get It From? Protein

!• Fish Meal Best, Most Common Source

Various Sources and Fish Commodity, Capelin, Anchovy, Herring Peru, Mexico, Canada producers Produced how?

• Plant and Other Animal Sources • Rendered feather and Blood meals • Corn and Soybean • Not as good a source, less digestible

Lipids (Fats)

• Inexpensive, Source cost varies • Type of fat important • HUFA’s most important

• Larvae, life or death

• Type and amount often customized • High energy salmonids, high HUFA larval

• Usually 10%-25% in diets

Fatty Acids

• Saturated FA • No double bonds in chain

• Unsaturated FA • At least one double bond

• Polyunsaturated FA • More than one double bond • HUFA’s included in this group

PUFA’s Essential

• Three most important groups are • Omega 3 (ω3), Linolenic acids • Omega 6 (ω6), Linoleic acids • Omega 9 (ω9), Olenic acids

• Essential Groups • ω3 are primary essential fatty acids • Most common deficiency of DHA and EPA

• Docosahexanoic acid, DHA, 22:6 n-3 • Eicosapentanoic acid, EPA, 20:5 n-3

Sources of Lipid for Diets• Fish Oil, Best source • Beef Tallow, mostly saturated • Corn oil • Canola oil

Deficiency, Total and Essentials• Increased disease incidence • Unexplained Mortality

Carbohydrates

• Not essential and very cheap • Many fish can not utilize well and excess can

cause disorders • Some species makes a good energy source • Sugars, Wheat (cellulose), Starch, other

grains • Not a component of the natural diet • Usually at around 12%-25% in diets

Ash

• Non digestible component of diet • Mostly bone from fish meal and other

minerals • Level usually 9% in diet

Moisture

• Amount of water in diet • Can vary from feed to feed and

manufacturer • Usually around 8%-10%

• Soft-Moist around 15%

• Higher moisture, faster degradation

Vitamins• Most important to balance in diet • 2 Groups

• Water Soluble – C, B’s, inositol, choline – Short retention time, leaching

• Fat Soluble – A, E, D, K – Long retention time, storage

• E and C antioxidants protect fats • Required amount vary between vitamins

Many Deficiencies Associated with Vitamin Deficiencies

• Fat Soluble !• A: exophthalmia, edema, eye lesions, ascites • D: tetany, lipoid liver, calcium imbalance • E: depigmentation, ascites, muscular dystrophy • K: prolonged clotting, anemia, hemorrhagic gills

and eyes

• Water Soluble !• B1 Thiamine: nervous disorder, Loss Equilib,

Convulsions, hyperirritability

• B2 Riboflavin: lethargy, dark skin, spinal def., photophobia

• B3 Niacin: skin fin gut lesions, photosensitivity, sunburn, ascites

• B4 Pantothenic acid: clubbed gills, distended opercula

• B5 Pyridoxine: nervous disorders, convulsions, spiral swimming

• B12: reduced growth, anemia

• Water Soluble (cont.) !• C Ascorbic Acid: intramuscular hemorrhaging,

distorted gills, spinal deformaties, ascites, impaired healing, increase infections

• Biotin: degenerative gills, skin lesions, muscle atrophy, convulsions

• Folic Acid: lethargy, slow growth, dark, anemia • Choline: fatty liver, exophthalmia, distended

abdomen, hemorrhagic gut and kidney • Inositol: dark, distended abdomen, fin erosion

Minerals

• Macro and Micro Minerals • Some are essential though in small

quantities • Many toxic but required in small amounts • Fish can absorb many from water • Seawater contains many minerals

Major Requirement

• Calcium • Phosphorous (essential for growth) • Magnesium • Sodium • Potassium • Chlorine (chloride) • Sulfur

Trace Minerals• Iron • Copper • Zinc • Manganese • Selenium • Iodine • Cobalt • Fluorine

• Molybdenum • Aluminum • Nickel • Vanadium • Silicon • Tin • Chromium • Etc…….

Mineral Deficiencies

• Calcium and phosphorous: poor growth, bone development impaired

• Magnesium: poor growth, anorexia, lethargy, flaccid muscles, increased mortality

• Iron: anemia • Selenium: decreased growth, muscle dystrophy

Mineral Deficiencies cont.

• Copper: growth depression, anemia • Iodine: goiter, thyroid dysfunction • Zinc: decreased growth • Manganese: decreased growth, abnormal tail

growth, spinal fusion

Diet Formulation

• Very species specific • Ingredients and vitamin requirements very

specific to species and age • Biology of animal will generally dictate need

Carp and Tilapia

• Long Guts, Grazers • Can digest more difficult to digest

ingredients; starch cellulose • Digest plant proteins better • High cellulose and less protein • Cheap diets

Catfish• Moderate gut length, Scroungers and

predators • Can utilize some plant protein • Can use low protein feeds if fed to satiation;

grower 24-28%, Fry 50%, fingerling 35% • Cheap feeds

Salmon and Trout

• Short guts, Pisciverous • Can not utilize plant proteins • Need 45% protein and 15% fat • Do not use carbohydrates well • Energy from protein and fat • Expensive diets

Other Feed Concerns

• Storage should not exceed 75° • Should last 6 months, dry diet, Moist diets

less; Vit E and C • Fat rancidity • Vitamin degradation

• Type of diet for age and stage of development • Fry vs. fingerling vs. grower vs. finishing

Broodstock Feeding

• Your eggs are only as good as your brood feed

• Brood are often overlooked and thus produce poor quality eggs

Feeding First Feeds, Dry

• Feed sizes vs. size of fish • Salmon, trout and catfish eat dry first feeding

• Marine fish need live feeds • Weaning to dry feed is goal in hatchery

• Why wean; improved growth and efficiency • Wet vs. Dry

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