CONICET | Buscador de Institutos y Recursos Humanos

Rabbit sperm have a high sensitivity to cryopreservation manifested in changes on the plasma membrane that affect their fertilizing capacity. Recent studies show that seminal plasma (SP) addition to frozen/thawed ram sperm improves their viability and fertility. In addition, there is evidence to suggest that components of SP enhance sperm survival within the female reproductive tract. The aim of this study was to evaluate the in vivo fertilizing capacity of frozen/thawed rabbit sperm of Californian breed incubated with SP. Twenty semen straws were thawed and incubated for 5 minutes at 37ºC with (10% v/v) or without homologous SP (T-SP and T-C, respectively). Twenty rabbit does were synchronized with eCG (60 UI) and were artificial inseminated with T-SP (n=10) or T-C (n=10). Ninety six hours after insemination time, uterine horns were flushed for embryo recovery with phosphate buffer solution (PBS) plus BSA (2%). Collected structures were evaluated under stereomicroscope and classified in blastocyst, degenerated embryos and oocytes. The embryo recovery rate was significantly higher in rabbits inseminated with sperm T-C (3.6 embryos/rabbit doe ± 4.08) compared to those inseminated with sperm T-SP (0.3embryos/rabbit doe ± 0.67) (Figure1).The recovery rate of unfertilized oocytes was significantly lower in rabbits inseminated with sperm T-C (3.2 unfertilized oocytes/ rabbit doe ± 2.82), compared with T-SP (5.5 unfertilized oocytes/ rabbit doe ± 4.5). In addition, 62.5% of the embryos obtained in T-SP were degenerate, while in T-C was obtained only 14.3%. Based on these results, T-SP has showed decreased fertilizing capacity compared to T-C. We conclude that incubation of frozen/thawed rabbit sperm with homologous SP decreased their fertilizing capacity.