| Popis: |
This study investigated the effects of exogenous estradiol on sex reversal in the Asian swamp eel (Monopterus albus) by evaluating the estradiol (E2) and testosterone (T) concentrations, gonadosomatic index (GSI), hepaticosomatic index (HSI) and the sex ratio. Fish (9.60 ± 0.92 g average initial weight; n = 3 per group) were fed with six different diets containing 0 (control), 20, 40, 60, 80 or 100 mg kg-1 dietary estradiol contents to apparent satiation for 15 months. Serum E2 and T concentrations were determined by radioimmunoassay. Levels of E2, GSI and HSI significantly increased while T concentrations and survival rates decreased as the exogenous estradiol levels were raised. Sex ratios did not differ significantly among all exogenous estradiol treatments, and there were no significant differences between the control group and the 20 mg kg-1 treatment group. Therefore, exogenous estradiol can maintain the female activity and delay sex reversal in M. albus. This study provides important information for successful reproductive management and may be exploited for the aquaculture of this species. |
