Effects of Different Levels of Vitamin E on Some Growth Parameters and Gonadal Histology of Tilapia Oreochromis niloticus L., 1758 Fingerlings

摘要

The effects of diets including different levels of Vitamin E (110.25 mg kg-1 feed (Control Group), 175 mg kg-1 feed (Group 1), 200 mg kg-1 feed (Group 2) and 250 mg kg-1 feed (Group 3)) on growth parameters, survival rate and gonadal histology of Oreochromis niloticus L., 1758 were examined in this study. Fish (20.62?±1.19 g and 10.33 ?±0.20 cm) was fed with Vitamin E enriched feed for 60 days. At the end of the experiment, the highest body weight, total length, daily growth rate, specific growth rate, condition factor and gonadosomatic index were in Group 1. Whereas, the best survival rate (100%) was taken form Group 2 and 3, lower rates (78 and 85%) were seen in the other groups. As to histological view, it was also observed that as Vitamin E levels increased growth stages of the ovarian and testis tissues. It was concluded from all results in this study that the most proper ratio of Vitamin E in the feed is 250 mg Vitamin E kg-1 feed for growth of O. niloticus of such size.