Sexual reversion of bullfrog with masculinizing hormone added to the tadpole ration

[摘要] - This work consisted in testing the efficiency of a masculinizing hormone (17b-hydroxy-17-methyl-androxy-4-en-3-one) in the sex reversal of bullfrog tadpoles. Three hundred and fifty two tadpoles with two or three months old, from the stages 30 to 36, were used to test four levels of hormone in the ration (0, 30, 60 and 90 mg/g), for 45 days. After metamorphosis, 167 juveniles were sacrificed and 185 were reared until the fourth month of age and sacrificed thereafter. Macroscopic analysis of the gonads and secondary traits confirmed the masculinization in the treatments with hormone. Many oocytes were observed in the testes of the masculinized juveniles; however, four months after metamorphosis the ovotestes were sporadic. It was concluded that, after metamorphosis, oocyte reabsorption started in reversed juveniles, culminating in almost total reabsorption at the fourth months.

[学科分类] 兽医学

[关键词] Rana catesbeiana;17b-hydroxy-17-methyl androxy-4-en-3-one;tadpoles   IntroduçãoOs machos e as fêmeas de rã-touro (Rana catesbeiana) criados em cativeiro apresentam crescimento diferenciado;porque;quando as fêmeas alcançam a pri-meira maturação sexual;passam a usar os nutrientes de sua dieta para a maturação dos ovários (RIBEIRO FILHO;1999)