Among the Vitamins, the antioxidants (Vitamin C and E) are found to have an impact on the immune system of fishes. Vitamin C and E improve survival and growth. Diets fortified with Vitamins C and E and Se raises levels of these antioxidants in the muscle. High levels of these antioxidants also results in an extension of the colour shelf life. Se, Vitamin C and Vitamin E increase growth performance, antioxidant capacity and immune response. Vitamin E protects cell membranes and tissues against oxidative damage. The inclusion of Se in the diet have benefits for production, reproduction and product quality. Selenium is required for normal growth, development and flesh quality. Selenium plays an important role in the maintenance of fish health, in particular fish immunity. Symptoms of Se deficiency in fish include low glutathione peroxidase activity, reduced growth, impaired reproduction, anaemia, exudative diathesis, muscular dystrophy and increased mortality. Vitamin E and Se function synergistically in animal tissues to form an important antioxidant defence system.

Ascorbic acid is a sugar acid with antioxidant properties and it is commonly known as Vitamin C Vitamin C is an antioxidant Vitamin needed for the formation of collagen to hold the cells together and for healthy teeth, gums and blood vessels; it improves iron absorption and resists infection. It acts synergistically with Vitamin E and selenium to maintain activity of glutathione peroxidase and superoxide dismutase. Vitamin C is responsible for maintaining iron in its reduced state, Deficiency of Vitamin C leads to impaired collagen formation, altered cartilage, eye lesions, haemorrhagic skin, liver, kidney, intestine and muscle. The fish show hyperplasia of jaw and snout. Hypertrophy of the adrenal tissues and haemorrhage at the bases of fins has been observed in the water soluble Vitamins are dietary essential for normal growth and physiological activity. reported that water soluble Vitamins are essential for Penaeusmonodon. Ascorbic acid is the most unstable one; so it should be added in fish diet as it is water soluble, but not L-ascorbic acid. There is also an inter- relationship among ascorbic acid, Vitamin-E and selenium. They also play an important role as antioxidants. To enhance fish production in the farming system one should add these Vitamins in fish feed Vitamin E and Se function synergistically in animal tissues to form an important antioxidant defence system. Selenium associated with supplementation of Vitamins C and E increases the weight gain of aquatic organisms Diet formulation enriched with Vitamin C and E and selenium increases weight gain feed conversion ratio