Feminization and growth of juvenile fat snook Centropomus parallelus fed diets with different concentrations of estradiol-17β

Abstract

In this study, we evaluated the effect of diets with various concentrations of estradiol-17β (E2) on the feminization, growth and survival of juvenile fat snook. Over a 45-day period, the juveniles were fed with five diets containing 0, 25, 50, 75 and 100 mg E2/kg feed. Three replicates were run for each diet. After this hormonal treatment, the fishes were transferred to 1-m3 net cages, where they remained for 12 months. During this period, they were fed a commercial diet without added hormones. During the feminization, the control fish grew more than those in the other treatments, and the survival rates did not differ significantly among the treatments. At the end of the experiment growth did not differ among the treatments. In the control treatment, 80.85 % of the fish were male, and the females were significantly larger than the males. All of the treatments with E2 produced 100 % females. No intersex fish were found in this study. This research showed that it is possible to obtain 100 % fat snook females using feeds with 25 mg E2/kg for 45 days without impairing the growth or survival of the fish.