The Effect of Estradiol Valerate on Sex Reversal of Rainbow Trout, Oncorhynchus mykiss

The effect of oral administration of 20 mg of estradiol valerate (E2V) per kilogram of administered diet was studied on sex reversal in 35-day-old (average 0.32±0.02 g) rainbow trout, Oncorhynchus mykiss. The E2V was treated for 56 days to fry. The research was carried out totally 355 days. At the end of this time, all fish were sampled, digested and analyzed for their sex determination and the Gonadosomatic Index (GSI) values of the E2V and control groups were calculated. Compared to controls, there were changes in sex composition of E2V treated fish. The sex composition of E2V treated fish was found as 97% of female and 3% inter-sex. However it was found as 51% of female and 49% male in the control fish. Gonadosomatic indices of the E2V and control groups were calculated as 0.12 and 4.21%, respectively. It was concluded that the determined application time, dose and period of E2V in this study were effective in direct feminization of rainbow trout.