Feasibility of phenotypic sex reversal in beluga and Persian sturgeon

Caviar of beluga (Huso huso) and Persian sturgeon (Acipenser persicus) are the most expensive in the worldwide market. Because of that, all female production is very important in these species. In this research, the effects of dietary 17-β estradiol on growth performance and sex reversal of beluga and Persian sturgeon were investigated. Initial mean weights of beluga and Persian sturgeon were 172 and 47g, respectively and stocking densities were 25 individuals per 1000-liter tank and 14 individuals per 200-liter tank, respectively. In both species, fish were fed 0 (control) and 30 mg estradiol/kg with two replicates for beluga and three replicates for Persian sturgeon. Results showed that the growth performance of both species was significantly affected by dietary estradiol 40 and 100 days after the beginning of the experiment, respectively. Histological assessment of gonad tissue indicated that females were predominant in both species comparing with the control group. Sex composition was 72.5% female, 17.5% male, and 10% undetectable in the hormonal treatment of beluga and 85% female, 10% male and 5% undetectable in the hormonal treatment of Persian sturgeon, but females were lower than 60% in the control group of both species. In conclusion, the dietary administration of estradiol was relatively successful in sex reversal of both sturgeon species. However, determination of the optimum level of estradiol requires more studies because of its negative effects on growth performance and fish health.