Feminization Of Oreochromis Niloticus Using Diethylstilbestrol

Abstract

Oreochromis niloticus (Nile tilapia) is one of the best choices for fish farmers. It is tolerant to adverse environmental conditions, it can survive at low dissolved O2, it is euryhaline, relatively fast growing and efficient in food conversion. However, it requires sex reversal for mono-sex culture, and particularly feminization of Oreochromis niloticus using diethylstilbestrol. Sex reversal can be achieved by harmonized fish feed. After four months of feminized fish, randomly sampled Oreochromis niloticus were dissected for gonad observation through compound microscope in the Zoology Laboratory at Masinde Muliro University of Science and Technology. The gonads were stained using a certocamine to make the observation possible. The pond with only females was a confirmatory of the right hormone concentration to be used. This study was to determine the right hormone concentration to feminize Oreochromis niloticus. Oreochromis niloticus was feminized by yolk sac fry immersion into Diethylstilbestrol for ten minutes, and then transferred to the ponds till yolk sac absorption. The fish was stocked into 4 ponds (0.8 x 1 x 1.4 M) at different Diethylstilbestrol concentrations. Diethylstilbestrol concentration was finally found to be 5mg for Oreochromis niloticus feminization. Water was pumped into the ponds from a water reservoir tank through horse pipes and individual ponds received their water independently It was concluded and recommended that right hormone concentration should be 5 mg for farmers and hatchery dealers.