Effects Of Exogenous Testosterone Propionate On The Sex Reversal Of Monopterus Albus (Zuiew)

Rice-field eel (Monopterus albus, Zuiew), a burrowing eel-like synbranchoid teleost, undergoes a natural sex change from female to male during its life history. It is widely distributed in fresh water systems throughout Asia. It has high commercial value and wild caught fingerlings are increasingly being cultured in China and south-east Asia country. However, rice-field eel's artificial propagation becomes a key-point for its cultivation with development of fishing and wild juvenile resources declined sharply.The studies purpose is that the effect of exogenous hormone by manual manipulation on M.albus sex reversal. Support M.albus Factory artificial propagation with theory and technological, besides M.albus sex reversal rational. To solve an important factor of rice-field eel artificial propagation that has too few male eel. Hoped that we can reduce the time of sex reversal and increase the proportion of male. To solve the subject of M.albus sex reversal and promotion of the sustainable development of rice-field eel aquaculture.Study the exogenous testosterone propionate on the sex steroid hormone secretion and effect of ricefield eel sex reversal, biological biopsy were female. We fed rice-field eel in the pond cages (2 m×1m×1.5 m) with different concentrations of testosterone propionate (0,20,40,60,80,100 mg/kg) for 15 months.Exogenous testosterone propionate on rice-field eel's serum steroid hormone levels has a seasonal effect. Different concentrations of testosterone propionate can inhibit the serum estradiol, and also can stimulate the increase of serum testosterone levels. Low concentration (20 mg/kg) of testosterone propionate on the reversal of rice-field eel had no significant promotion, however, high concentrations(40,60,80,100 mg/kg) can promote the reversal of rice-field eel. Statistics of the ratio of male eel were 6.95±3.15%, 7.06±3.32%,41.27±13.75%,43.95±6.53%,61.34±8.24%,69.38±11.03%, and has reversed to the male sex gonadal development of fishes completely. The results showed that the concentration of exogenous testosterone could promote the reversal of rice-field eel.