The use of mGnRHa provokes ovulation but not viable embryos in Leporinus macrocephalus

• Autor(a) principal: Pereira, T. S.B. [UNESP]
• Data de Publicação: 2017
• Outros Autores: Boscolo, C. N.P. [UNESP], Moreira, R. G., Batlouni, S. R. [UNESP]
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://dx.doi.org/10.1007/s10499-016-0049-2; http://hdl.handle.net/11449/173346
• topic: Final maturation; Gonadal steroids; Hormonal treatment; Ovulation; Spawning performance

In rheophilic tropical fish, the use of carp pituitary extract (CPE) is still the main protocol since the use of gonadotropin-releasing hormone (GnRH) induces ovulation, but usually does not provide viable embryos. Thus, in order to generate knowledge to support the establishment of a successful protocol using GnRH, we compared the ovulatory process and reproductive performance of Leporinus macrocephalus using CPE (0.5 and 5.0 mg kg−1) and mGnRHa (7 µg kg−1) associated with metoclopramide. Females of both treatments ovulated, but the mGnRHa treatment did not provide viable embryos, which was associated with a more potent ovulation, lower latency period and less intense hydration of eggs, suggesting a possible treatment overstimulation. This is the first report associating a less intense egg hydration process to a failure in obtaining viable eggs in induced fish spawning. Considering that the mGnRHa doses applied here were quite low, it is possible that L. macrocephalus as well as other rheophilic tropical species present a higher sensibility to mGnRHa and/or metoclopramide (or derived substances) and future approaches must consider using even lower doses of these substances as well as testing different types of GnRH and dopamine inhibitors.