Induced reproduction of piauçu, Leporinus macrocephalus Garavello and Britski, 1988 (Characiformes, Anostomidae)

Abstract

In captivity conditions, the majority of the migratory species does not dispose if they do not receive stimulations necessary to complete the reproductive process. Then, many works has been developed aiming to find the best technique in order to induce the reproduction in each species. The present study was carried out in the Piscicultura Panama, Paulo Lopes, SC. Thirty-six reproducers of piauçu, Leporinus macrocephalus, between males and females were used, aiming to evaluate the technique of induction to reproduction. Two protocols of hormonal induction had been tested, with two and three doses: 0.5 and 5.0 mg EPC/kg, and 0.25; 0.5 and 5.0 mg EPC/kg. Amongst the fishes treated with three doses of hormones, the natural spawning and that through extrusion were tested. It was observed that the fertilization rate is similar when using two or three doses of hormone (P>0.05), with average value of 95.5%. The natural spawning of fishes provides greater rate of fertilization of eggs (94.5 ± 3.3%), when compared with the spawning of fishes by means of extrusion (25.8 ± 25.3%) (P<0.05), as well as bigger rate of survival of the reproducers, with values of 100% and 66.7%, respectively.