Effect of orally-administered 17?-Methyltestosterone at different doses on the sex reversal of the Nile tilapia (Oreochromis niloticus, Linneaus 1758)

In order to obtain all male population, the Nile tilapia (Oreochromis niloticus) larvae which just finished the yolk sac were fed with feed containing 17?-Methyltestosterone at five different doses (0, 20, 30, 40, 50 and 60 mgMT kg-1 feed) for 28 days. As a result of the experiment repeated twice, it was found out that the sex reversal rates among the groups were at the levels of 57.1, 69.8, 69.4, 70.9, 86.1 and 93.7%, respectively. Furthermore, it was observed that the highest sex reversal rate occurred in the group to which 60 mgMT kg-1 feed dose was applied. © Medwell Journals, 2011.