Feed Efficiency, Fish Performance & Water Clarity Rick Decker AquaMax Fish Diets
Fish Nutrition Why feed fish? Why is nutrition important? What nutrients are essential? How are nutrients determined in an ingredient or a diet? How does the animal use its food? How does a feed affect water quality? What should be provided in a good fish diet?
Why feed fish? Commercial fish operations Grow fish in hobby ponds Attract fish Ponds, lakes, streams Get the equivalent of 3 years growth in one season
Why feed fish? Effect of Supplemental Feeding on Fish (Kansas Fish & Game Commission) During a 3-year span: Bluegill numbers per acre increased 211% Bluegill weight per acre increased 310% Size of fish increased 143% Total pounds of all species of fish increased 187%
Why is nutrition important? Nutrition provides an animal with all of the building blocks to grow, reproduce, fight infection and maintain health Nutrition must be supplied Diet Water Air
Why is nutrition important? NRC requirement Production parameter (growth, reproduction, immune function ) Deficient Marginal Adequate Marginal Optimal Conditions Toxic Deficient Marginal Optimal Under optimal conditions, nutrition doesn t have to be perfect But in times of stress, nutrient levels are much more critical - Disease - Poor water quality - Physical or environmental stress (e.g., transportation, handling) Marginal Stressful Conditions Toxic
BASIC NUTRITION Series of processes by which an organism takes in and assimilates food for maintenance, growth, production and reproduction
What nutrients are essential? Oxygen Water Amino acids / Protein Fatty acids / Lipids Vitamins Minerals Energy Carbohydrates* *Not essential
ENERGY Not a nutrient, but provided by nutrients Protein/amino acids Lipids/fatty acids Carbohydrates
Carbohydrates Various combinations of carbon and water - Plants use for energy storage and structure - Animals use for metabolic energy - Includes: - Fiber components - Structural - Hemicellulose, cellulose, lignin - Non-fiber components - Sugars glucose, fructose, sucrose - Starches amylose, glycogen http://www.factmonster.com ipka/a0775714.html 9/06
Carbohydrates - Fiber components - Hemicellulose, cellulose, lignin - Generally require microbial digestion - Non-fiber components - Sugars glucose, fructose, sucrose - Starches amylose, glycogen - Generally are digestible by the animal Glucose Cellulose Amylose http://es.wikipedia.org/ 9/06
Amino acids / Protein Amino acids are the building blocks of all proteins including - skeletal muscle and other tissues - scales, skin, fur, feathers - hormones and signaling molecules - immune defenses ~ 20 amino acids and ~ 10 are essential Lysine Cysteine http://es.wikipedia.org/ 9/06
Amino acids / Protein Generally the most expensive dietary component 100s of scientific papers on the replacement value for a protein source compared to fishmeal Quality is more important than quantity! - must have the right balance of amino acids - high quality fishmeal is always the gold standard
Fatty acids / Lipids - Carbon, Hydrogen and Oxygen -Most concentrated form of energy storage -Generally long-term energy storage -Major forms - Triglycerides (3 fatty acids + glycerol) - Phospholipids and other membrane components - Cholesterol - Sterol hormones -Some fatty acids are essential -Some lipids are essential http://www.raw-milk-facts.com/images/cholesterol2.gif 3/08
Fatty acids / Lipids -Physical properties of lipids are based on the # of double bonds (aka unsaturated) -More double bonds (more unsaturated) Less able to become a solid when temperature drops http://www.chm.bris.ac.uk/motm/ethylacetate/sattriglyceride.gif 3/08 http://www.chm.bris.ac.uk/motm/ ethylacetate/triglyceride.gif 3/08
Fatty acids / Lipids Ruminant fat (beef, lamb, goat) More saturated, Fewer double bonds Poultry and pork fat Mix of saturated and unsaturated Some double bonds Fish oil Mostly unsaturated Many double bonds
Fish Diets When Fish Eat Fish Is it Dangerous?? Fishmeal comes from domestic menhaden Harvest is regulated by NOAA (National Oceanic & Atmospheric Assoc.) SAFE Sustainable Efficient
Vitamins Chemical compounds required in relatively low amounts Biochemical Co-enzymes Molecular Regulators Hormone - Vitamin D - Fat soluble A, D, E & K -Stored with fat, primarily in the liver - Harder to excrete excess - Water soluble thiamin, niacin, pantothenate, pyridoxine, B12, biotin, riboflavin, folate, choline, ascorbate -excess can be excreted
Carotenoid pigments 600 + known carotenoids; ~ 50 vitamin A precursors Found in plant & animal products, but only made by plants Function as pigment (skin, muscle, fat, egg yolk) Important for mating success Important for marketing food Function as an antioxidant / immune modulator www.plantations.cornell.edu/ images/tomato.jpg
Minerals Functions Structure (e.g., Ca, P, Mg, Mn, S) Acid-base balance & osmoregulation (e.g, Na, Cl, K, S) Metalloenzymes (e.g, Fe, Zn, Cu, S) At least 21 known to be required Macrominerals - Ca, P, Na, Cl, K, Mg, S Microminerals - at least 14 Ultratrace minerals
Nutrient determination Proximate Analysis Moisture Crude Protein (amount of N multiplied by 6.25) Limitation no amino acid profile Some N is not protein (e.g., urea) Crude Fat Limitation no fatty acid profile - Crude Fiber - Ash (minerals) - Nitrogen free extract (NFE) 100- moisture- protein fat- fiberash NFE= Starch & Sugars
Nutrient determination Proximate Analysis Represents what is needed for tag guarantees Provides relatively inexpensive method of checking broad classes of nutrients Does not provide precision or individual nutrient Does not provide precision or individual nutrient determination
DIGESTION Small Intestine - Enzymatic Degradation Carbohydrates: Amylases, Lactase, Sucrase Fats: Bile Salts, Lipases Proteins: Proteases, Trypsin, Chymotrypsin, Peptidases
Digestion and Absorption Varies between species due to wild type diet Carnivore (meat eater- zooplankton to mammals) Omnivore (variety of foods, may have seasonal changes Herbivore (plant eater phytoplankton to aquatic plants Varies between species due to environment Terrestrial vs. aquatic Environmental temperature (cold-blood animals)
DIGESTION Consumed Absorbed* Carbohydrates Simple Sugars Fats Fatty acids, glycerol Proteins Amino acids *Absorbed into blood or lymph
GI TRACT Reflects an animal s eating habits Complexity Length
Digestion and Absorption Terrestrial, warm-blooded herbivore GI tract/body length ~ 35 Long, complicated GI tract to extract maximal nutrients from plants Stevens and Hume, 1996
Catfish: B.L. = 58 cm G.I.T. = 114 cm G.I.T.:BL = 1.97
Bluegill: B.L. = 20 cm G.I.T. = 24 cm G.I.T.:BL = 1.2
Brook Trout B.L. = 25.5cm G.I.T. = 18.5cm
FISH vs. TERRESTRIAL ANIMALS Fiber Utilization No foregut fermentation Little or no hindgut fermentation Mastication/grinding Koi - pharyngeal teeth Milkfish, gizzard shad - gizzard Grass Carp
FISH vs. TERRESTRIAL ANIMALS 1) FCR Cattle = 6-8 Hogs = 3 Chickens = 2-3 Fish = 1-2 2) Dietary Energy and Protein Much less energy - gravity, polkilothermic (cold blooded) More dietary protein 3) Minerals Dietary Ca requirement? (readily available in water)
FISH vs. TERRESTRIAL ANIMALS 4) Omega - 3 fatty acids - required by some fish Eicosapentaenoic Acid (EPA) 20:5, n-3 Docosapentaenoic Acid (DPA) 22:5, n-3 Docosahexaenoic Acid (DHA) 22:6, n-3 5) Vitamin C Cartilage synthesis Water soluble antioxidant Disease resistance
Fish Diets Which diet to choose for your fish -Appropriate for it s feeding strategy Carnivorous: Trout, Bass, Perch, bluegill All Starting fish Protein-based diets Omnivorous: Catfish, Carp, Koi, Tilapia Can utilize some carbohydrates
High Quality Fish Diets Should Be: Manufactured only with Domestic Sources of Fishmeal and Fish Oil (Bio Security) Manufactured only with highly digestible ingredients Utilize extrusion technology to get the best absorption in aquatic species Be available to you on a timely basis in reasonable quantities