| Sumario: | Vitamins are organic substances that are essential for growth, health, reproduction and maintenance in animals, butrequired in small amounts. Since fish cannot synthesize vitamins at all or can only synthesize in insufficient quantityfor normal development, growth and maintenance, they must be supplied in the diet. In comparison to terrestrialanimals, the information available on vitamin requirement of aquatic species still lacks depth. Other than the 13known vitamins, i.e. thiamin, riboflavin, niacin, pantothenic acid, biotin, folic acid, vitamin B6, B12, C, A, D, E andK, their requirements have been quantified in tilapia, the essentiality of choline and inositol for tilapia have alsobeen demonstrated. Vitamin E and B6 requirements for tilapia are closely related to dietary lipid and proteinconcentrations, respectively. 42-44 and 60-66 mg vitamin E/kg diet are required for maximal growth of tilapia feddiets with 5 and 12% lipid, respectively; whereas, 1.7-9.5 and 15.0-16.5 mg vitamin B6/kg diet are required fortilapia fed diets with 28 and 36% protein, respectively. Niacin requirements in tilapia varies with the carbohydratesource in diet. Optimum dietary levels of niacin for maximum growth have been reported to be 26 mg/kg diet fortilapia fed a glucose diet, whereas 121 mg/kg diet is needed for fish fed a dextrin diet. Tilapia produces vitamin B12in their gastrointestinal tract through bacterial synthesis. Thus, no dietary B12 is needed for tilapia. Vitamin C(L-ascorbic acid, AA) requirements of tilapia is 79 mg AA/kg diet. When vitamin C stabilizers, L-ascorbyl-2-sulfate(C2S), L-ascorbyl-2-monophosphate-Mg (C2MP-Mg) and L-ascorbyl-2-monophosphate-Na (C2MP-Na), are usedas the vitamin C source, the requirement level are 20-23, 17-20 and 16 mg AA/kg diet, respectively. Dietary vitaminA requirements of tilapia is 5,850 to 6,970 IU/kg diet. Tilapia is able to utilize β-carotene to fulfill the dietaryvitamin A requirements. The conversion ratio by β-carotene to vitamin A is approximately 19:1.
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