Evaluation of the effects of dietary vitamin C, E and Zinc supplementation on reproductive performance of Nile tilapia (Oreochromis niloticus)
M. GAMMANPILA*, A. YAKUPITIYAGE AND A. N. BART
A 3×2 factorial experiment was conducted to evaluate the effects of dietary vitamin C, E and Zinc supplementation on growth, survival and reproduction of Oreochromis niloticus in hapa based system installed in earthern ponds for 5 months. The triplicate groups consisting 30 fish were fed three levels of vitamin C (0, 50 and 1250 mg kg-1 diet), two levels of vitamin E (0, 600 mg kg-1 diet). An additional treatment that supplemented Zinc at a rate of 120 mg kg-1 with higher vitamin C and E levels was also included in the experiment. The results revealed that vitamin C deficient female fish exhibited significantly lower weight gain compared to the fish fed with diet supplemented with higher vitamin C. The spawning efficiency, total seed production and number of eggs per spawner were not affected by dietary vitamin C or E supplementation. However, the total number of spawns in hapa were significantly higher in fish fed with the Zinc supplemented diet compared to those fed with other experimental diets. The brood fish fed diets supplemented with 1250 mg kg-1 vitamin C and 600 mg kg-1 vitamin E had a significantly higher mean clutch size compared to the fish fed with other diets except the fish fed with 50 mg kg-1 vitamin C and 600 mg kg-1 vitamin E in the diet. The hatching rate and larval survival rate of the fish were significantly affected by feeding the fish 1250 mg kg-1 of vitamin C. Fish fed with a diet without vitamin C had reduced sperm viability and sperm motility compared with the fish fed with supplementary vitamin C (1250 mg kg-1) in the diet. The present study suggests that supplementation of vitamin C, E and Zn would improve the total number of spawns, total seed production, mean fecundity, hatching rate, sperm motility and sperm viability of O. niloticus. However consistent interactive patterns among tested levels of vitamin C, vitamin E and Zn were not evident in O. niloticus in relation to the reproductive performance parameters tested.