Effects of dietary estradiol-17β on feminization, growth and body composition in the Japanese eel ( Anguilla japonica)

Abstract

1. 1.Juvenile Japanese eels ( Anguilla japonica) were fed on a diet supplemented with estradiol-17β (E 2) at doses of 25, 50 and 75 mg/kg. The effects on growth, sex distribution and body composition were investigated in two groups of gonadally undifferentiated stages (early and later juvenile stages). 2. 2.Feminization (95–100%) was observed in all E 2-treated groups. 3. 3.The growth rate of fish treated with 25 and 50 mg/kg E 2 diet at the early juvenile stage was significantly increased. 4. 4.The amount of protein in muscle decreased and that of fat increased in the E 2-treated groups except in the early juvenile stage fed with 25 mg/kg E 2.