EFFECTS OF THE USE OF 17Β-ESTRADIOL FOR Leporinus macrocephalus FEMINIZATION

The aim of the study was to establish an effective feminization protocol for Leporinus macrocephalus using the 17β-estradiol (E2). Thus, one hundred and fifty fingerlings with 50 days old post-hatch were randomly distributed in fifteen experimental tanks of 90L and fed for 60 days on a diet supplemented with 50 or 100mg Kg-1 of E2. At the end of the experiment, sex ratios were determined through histological and macroscopic observations. Histologically, the differentiated ovaries were evidenced by the presence of numerous nests of oogonia and oocytes in primary growth stage. The female ratio (73%) for the group treated with 100mg Kg-1 E2 was significantly higher than those of control (52%) and 50mg Kg-1 treatment (48%) groups. These results indicate that 100 mg Kg-1 E2 administered for 60 days was the most effective treatment for 50 days old L. macrocephalus post larval feminization. In conclusion, the successful sex control can be achieved through dietary hormonal manipulation. However, future studies should be conducted to evaluate the economic feasibility of this technique.