Cryopreservation of Piau-Breed Wild Boar Sperm: Assessment of Cooling Curves and Centrifugation Regimes.

ABSTRACT

This study aimed to assess the effects of different cooling curves and centrifugation regimes used in cryopreservation protocols on the post-thaw viability of Piau-breed wild boar (Sus scrofa) sperm using in vitro assessment tests. Two centrifugations (800 g for 10 min and 2400 g for 3 min) and two cooling curves (conventional cooling using nitrogen vapour - freezing 1 and automated cooling using a programmed freezing machine - freezing 2) were tested. Therefore, the treatments were divided into M3 - centrifugation at 2400 g for 3 min and freezing 2; M10 - centrifugation at 800 g for 10 min and freezing 2; R3 - centrifugation at 2400 g for 3 min and freezing 1; and R10 - centrifugation at 800 g for 10 min and freezing 1. No significant differences (p > 0.05) between treatments occurred post-thawing regarding the total sperm motility means recorded. The mean values of the different treatments were not different from each other regarding the supravital staining (SV), hypo-osmotic test (HO), sperm-egg binding assay or sperm morphology. This study showed that both the cooling curve and the centrifugation regime affected the quality of post-thaw sperm, and centrifugation for shorter times and cooling curves using automated cooling are the most suitable for minimizing sperm injury.