Vitamin and Dietary Requirement

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Vitamins and Minerals

General Concepts:
* Divided into two major groups: fat soluble and water soluble * fat soluble: A, D, E, K
* requirements vary with species, size, growth rate, environment (temperature, presence of toxins, etc.) and metabolic function (growth, stress response, disease resistance) * many species can utilize intestinal bacteria synthesis for meeting vitamin requirements

Vitamin A: retinol

* Can only be found intact in animal sources
* in its natural form, it is alcohol known as retinol
* also isolated from various lipids and beta carotene
* 1 beta carotene (plants) = 2 retinols (body)
* stored in the liver
* retinol + opsin (protein) = rhodopsin (vision)
* deficiency = improper growth, exophthalmia
* feeds contain non-oxidizable form, proper storage
* requirement level = 1,000 I.U. (international units)
* sources: fish oils

Vitamin D3: cholecalciferol

* Vitamin D found as ergocalciferol (D2) and cholecalciferol (D3) * most land animals can use both, except chickens (only D3) * fish appear to use only D3
* both activated in plants/animal skin by UV radiation
* D3 primarily used as precursor for calcium regulation

Vitamin E: tocopherol

* Active form is alpha tocopherol
* good antioxidant: most feed antioxidants have vit E activity, but only 1/6 that of -tocopherol * antioxidants used to prevent oxidation of lipids (mainly phospholipids) * requirement is to selenium deficiency (Se is cofactor in glutathione peroxidase) * deficiency in fish = muscular dystrophy, reduced fertility * increased dietary requirement in absence of vitamin E

* requirement: 50-100 mg/kg for fish/shrimp
* sources: alfalfa meal, fish meal, rice bran, wheat , barley grains

Vitamin K: menadione
* Originally identified as a fat-soluble factor required for normal blood clotting * menadione is the most active form
* actually works by activating blood-clotting proteins
* requirement: shrimp (none), fish (unknown)
* dietary sources: alfalfa meal, liver meal

Water Solubles: thiamine (B1)
* Function: metabolism of COH
* sources: yeast, wheat, rice bran, rice polishings, wheat bran, soybean meal * deficiency: central nervous system failure
* requirement: 2.5 mg/kg (tilapia), 10-15 mg/kg (salmon) * requirement: 40-50 mg/kg (shrimp)

Riboflavin: B2
* Function: metabolic degradation of proteins, COH, lipids * sources: plants, bacteria, yeast, fish solubles
* deficiency: cataracts (fish), vision, crooked limbs
* requirements: 9 mg/kg (channel catfish), 5 mg/kg (tilapia) * requirements: 50 mg/kg (shrimp)

Niacin
* Function: transport of hydrogen ions as NADP, NADPH; electron transport, fatty acid, cholestrol synthesis * forms: niacin, nicotinic acid, nicotinamide
* sources: rice polishings, yeast, rice bran
* deficiencies: pelagra, dermatitis, anemia (fish), skin lesions (fish), sunburning (fish) * requirements: 14-28 mg/kg (carp, catfish)
* requirements: 400 mg/kg (shrimp)

Folic Acid
* Recently shown as very important for pregnant females to avoid birth defects * function: synthesis of purines, pyrimidines, nucleic acids * sources: yeast, alfalfa meal, full-fat soybeans

* deficiencies: anemia, large erythrocytes, pale gills (fish) * requirements: 1-4 mg/kg (fish, shrimp)

Cyanocobalmine
* chemically complex, cobalt nucleus
* function: coenzyme in metabolic reactions, maturation of erythrocytes, uracil->thymine * deficiency: pernicious anemia, nerve disorders
* requirement: very low 0.015 mg/kg or not at all

Ascorbic Acid: C
* Both finfish/shellfish very sensitive to this vitamin, especially as juveniles * function: antioxidant, stress reducer, bone calcification, iron metab,...
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