Effect of sex reversal in rainbow trout (Oncorhynchus mykiss Walbaum) using 17a-methyltestosterone and 11B-hydroxyandrostenedione      [RESEARCH ARTICLE]

  • Henryk Kuzminski
  • Stefan Dobosz
Keywords: sex control, GSI, rainbow trout, sex reversal


The aim of the experiment was to compare the effectiveness of sex reversal in mature female rainbow trout using 17a-methyltestosterone (6 ppm-MT) and 11$-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.


H. Kuźminski [+], S. Dobosz
Department of Salmonid Research Rutki
The Stanisław Sakowicz Inland Fisheries Institute in Olsztyn
83-330 Żukowo, Poland
Tel. +48 58 6818427; e-mail: hkuzminski@infish.com.pl