Sex Reversal in Tawes Puntius gonionotus by Oral Administration of Methyltestosterone

Abstract

An androgen, 17 alpha methyltestosterone (MT-Sigma), was orally administered to 7 14 days old tawes, Puntius gonionotus at the dodages of 0, 30, 60 and 120 mg/kg diet with treatment durations of 30 or 60 days. Growth reduction was observed during the first month in the groups treated with either 60 or 120 mg MT/kg diet. Hormone treatments did not affect the survival at 5 months. The administration of MT for 30 days enhanced sex reversal to male in some treated fish. Hormone treatment for 60 days resulted in high level of sterility regardless of dose or timing. The treatments initiated at 14 days post-hatch were more effective than those started at 7 days after hatching. The gonads of sex reversed fish showed typical anatomy of ovary but contained various stages of spermatogenic cells including spermatozoa. The sterile area in which no recognizable germ cells were detected, was observed in the sex-reversed gonads.