Chemistry/Biology Warm-up. Dr. Craig Kasper. Basic Elements*. Element Symbol Common Forms Carbon C CO, CO 2 , C n H n O n , COOH Hydrogen H H 2 , H 2 0, Oxygen O O 2 Nitrogen N N 2 , NO 2 , N0 3 , NH 3 , NH 4 + Phosphorus P PO 3 - , PO 4 Sulfur S S, HS -
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Chemistry/Biology Warm-up Dr. Craig Kasper
Basic Elements* ElementSymbolCommon Forms Carbon C CO, CO2, CnHnOn, COOH Hydrogen H H2, H20, Oxygen O O2 Nitrogen N N2, NO2, N03, NH3, NH4+ Phosphorus P PO3-, PO4 Sulfur S S, HS- *Keeping a periodic table of the elements around isn’t a bad idea.
Nutrition Feed Conversion Ratio/Feed Efficiency (FCR/FE) Protein Synthesis Protein Turnover Energy Nutrient vs. Non-nutrient Feed rate (fixed vs. satiation) Pelleted vs. Extruded Diets Heat (loss) Fecal Composition of Gain (protein vs. fat) Calorie Growth Maintenance Protein Lipid (fat) Carbohydrate Cholesterol Vitamin Mineral Amino acid Fatty acid Requirement Essential vs. non-essential Digestion Metabolism Feed formulation Feed ration Everyday Nutrition Terms
Everyday Biology Terms • Poikilothermy (-ic) • Temperature • Density • Ammoniotelic • Teleost
Think Like A FISH!! • Several factors make fish nutrition more challenging (and exciting) than that of terrestrial nutrition. • You must think like a fish, understand it’s evironment and understand basic nutrition before you will be able to maximize your fish growth or reproductive performance.
Zoological • Oddity: >40,000 species of fish exist (Compared to 167 species of chicken, or a dozen, or so cows and pigs, this means much more potential work). • Result: Large interspecific diversity. Variability of requirements.
Biological • Oddity: a. Larval Stages b. Continuous growth c. Potential absence of stomach • Result: a. Unknown factors b. Age-specific nutrient needs c. Unique digestive processes
Ecological • Oddity: Low average body temperature. • Result: Limited gut bacterial action? Difficulty maintaining membrane fluidity. Unique requirement for certain fatty acids.
Ecological • Oddity: Highly dense environment AND low oxygen availability. • Result: -Need for considerable ventilation. -Frequent use of anaerobiosis, hypertrophy of white muscle.* -Large amount of protein needed for synthesis of this material. -Reduced importance of skeleton -Low requirements for Calcium and Phosphorus (*REM: glycolytic=low oxygen)
Ecological • Oddity: Environment rich in certain elements! • Result: Supply of some nutrients directly from environment. • Oddity: Unique aquatic food chains (carnivores dominate). • Result: Different efficiencies of energy sources (much protein catabolism and limted carb. use.)
Ecological • Oddity: Abundance of polyunsaturated fatty acids. • Result: Loss of bioconversion ability.
Fish Nutrition History Dr. Craig Kasper FAS 2240C
What is fish nutrition? “Nutrition is the process by which an organism ingests, assimilates and utilizes various nutrients and converts them into body tissues and/or activities.” –Robinson et al. 2001
What is Nutrition? • Nutrition: the provision of all indispensable nutrients in adequate amounts to insure proper growth and maintenance of body functions • involves various chemical reactions and physiological transformations which convert foods into body tissues and activities • involves ingestion, digestion and absorption of various nutrients • transport into cells • removal of unusable elements and waste products of metabolism
History of Nutrition I • Lavoisier is generally credited as being the “father” of nutrition • until the first quarter of 19th Century, we thought the nutritive value of food resided only in one component • near the end of the 19th Century research started to focus primarily on the need for protein, lipids and carbohydrates • minerals were considered important, but their essentiality was unknown
History of Nutrition II • Great expansion in 20th Century nutrition with the discovery of vitamins, role of amino acids, more minerals • Your body needs >40 nutrients for normal growth and maintenance (fish may be even more.) • Why all the attention??? Human health/problems. • Basic studies of the functioning of the animal organism supplemented research
History of Nutrition III • Example of historical nutritional research: • heifers fed wheat-based diets produced calves at lower rates than those fed corn diets • assumption: something toxic in wheat • analysis: nothing toxic in tissues • reality: vitamin deficiency • scientific methods for formulating feeds were inadequate • research diets eventually simplified/purified
History of Nutrition IV • First vitamin discovered in 1913 • pioneer nutritional work achieved primarily through the use of animal subjects • same today, but with restrictions • rats vitamins, amino acids, minerals • dogs insulin, nicotinic acid • guinea pigs prevention of scurvy • chicks thiamin and other vitamins • bacteria growth factors, nutrient function in metabolism • final answers must be derived from species studied
Nutrition Today Animal nutrition today is multidisciplinary: • metabolism: physiologists, biochemists • vitamins: organic chemists • isotopes/chromatography: physicists • protein structure: molecular biochemists • breed variation: geneticists • vitamins/amino acids: microbiologists • additives/improved digestibility: food technologists
Issue: Overexpansion • Everyone now-a-days appears to be an expert in nutrition • infomercials, algae, diet fads • claims of superiority without scientific evidence (science vs. pseudoscience) • example: massive doses of vitamins are useless, often toxic • nutrition industry might need to become more conservative • it’s no wonder why the average consumer is puzzled!!
Nutrient Essentiality • essential nutrient: one that must be provided in the diet in order to insure adequate growth and maintenance, indispensable • Nutrient categories: macro and micro • macronutrients: protein, lipid, carbohydrate, etc. • micronutrients: trace metals, vitamins • important: molecular weight is not the basis, requirement level is • proteins: g/kg vitamins: µg/kg • large requirement doesn’t imply greater importance (example: Se in sheep 0.1 mg/day)
Basic Nutritional Concepts • Animal nutrition is tied back to food crops and ultimately to the nutritive value of soil • strong interrelationship between human and animal nutrition • foods/feeds of both contain similar nutrients • metabolic processes are basically similar • nutritional niche of animals: animals concentrate nutrients of food crops into more nutritious and palatable forms for humans • point:animals take sources unsuitable for humans and improve their quality for us!
Animals as Primary Consumers • Animals produce meat, milk, etc. on land that is often unsuitable for production of food crops • problem: overall land availability vs. protein demand • fisheries flat, agriculture barely keeping up • nutrition has greatly improved production capacity, however it is not going to be enough
What Does it All Mean? • If agriculture is barely keeping up with world food demand and… • Fisheries are being improperly managed to the point of steady state… • Either we must quickly apply Iowa corn field technology to all aerable land on Earth, or food must be found from other sources! (Roaches??) • One possible option is aquaculture.
Current Challenges/Problems • For aquaculture to contribute more to the world’s food supply, production must be intensified • higher yields must be achieved in ponds • better and more predictable natural sources of nutrition (natural productivity) must be available (too unpredictable) • more crude feed materials used as supplements or… • compounded feeds must provide all nutrients • retention vs. digestibility: Which is best metric?
Next Time… • Quiz 1: Terminology • Topic 2: Fish Behavior, Feed Intake, Environmental Factors (Why are aquatics different than terrestrials?)