Effect of sex reversal in rainbow trout (Oncorhynchus mykiss Walbaum) using 17α-methyltestosterone and 11β-hydroxyandrostenedione

The aim of the experiment was to compare the effectiveness of sex reversal in mature female rainbow trout using 17α-methyltestosterone (6 ppm-MT) and 11β-hydroxyandrostenedione (20 ppm-OHA). Hormones were administered with the first exogenous feed for up to 60 days. Among the fish treated with OHA, 95% females were reversed into mature neo-males and 1.6% to bisexual individuals. Among the fish treated with MT only, 59.7% females were reversed to neo-males and 1.8% to bisexual individuals. Functional neo-males were 1.6% and 5.3%, respectively. The rest of the neo-males had obstructed seminal vesicles in various stages. The gonadsomatic index was 3.9% at age 3+ in both groups of mature fish. The shape of the testes ranged from elongated to stunted. The bisexual fish had immature oocytes and mature testes with viable semen that was used for egg fertilization.