Fish Nutrition & Feed Technology

Unit 9 - Nutritional requirements of cultivable fish and shell fish

9.8.Vitamins and minerals

Vitamins are required in traces which are essential for fish growth and health. They are also required for metabolism of other nutrients. Many of the water soluble vitamins act as co-enzymes. Fishes derive required vitamins from natural food, which become limited in intensive fish culture due to high stocking densities, while minerals are required for osmotic balance of various metabolic process and for structural functions in fish. Some minerals such as calcium are directly obtained by fish through gills and skin or both, while others are made available from natural food and ingested detritus. Vitamins and minerals are, therefore, provided as premix in formulated feeds.

Fish require 11 water soluble vitamins, namely thiamine, riboflavin, pyridoxine, niacin, pantothenic acid, inositol, folic acid, choline, biotin, ascorbic acid and B12 along with four fat-soluble vitamins such as A, D, E and K. Water soluble vitamins, when taken in excess are excreted. However, excess fat soluble vitamins in the diet results in abnormal growth and liver diseases.

There are more than 20 recognized mineral for performing essential functions in the body. The minerals required by fish are calcium, phosphorus, magnesium, sodium, potassium, chlorine, and sulphur along with a number of trace elements such as cobalt, copper, iodine, iron, manganese, selenium, zinc, aluminum, chromium and vanadium. Calcium and phosphorus are closely related in metabolism and constitute major part of skeletol system. Calcium plays a major role in blood clotting, muscle function and proper nerve impulse transmission. Phosphorus is involved in energy transformation, permeability of cellular membrane, genetic coding and general control of reproduction and growth.