57 TREHALOSE SUPPLEMENTED EXTENDER PRESERVE ACROSOMAL INTEGRITY IN POST-THAW BOAR SPERM

Cryopreservation of boar semen is still considered suboptimal due to lower fertility when compared to fresh semen. The use of glycerol for boar semen cryopreservation may be a reason of low fertility results. Trehalose is a nonreducing disaccharide known to stabilize proteins and biologic membranes during processes such as cryopreservation. The aim of this study was to evaluate the effects of trehalose on boar sperm cryosurvival in an egg-yolk-based extender. The semen samples collected from different individual Berkshires were diluted in egg-yolk-based freezing extender containing glycerol (final concentration 68.5 and 274 mM) or trehalose (50 and 100 mM). Then the samples were cryopreserved using the straw freezing procedure. Frozen sperms were thawed at 39°C in water. Post-thawed sperm were analyzed for motility (under microscope by a conventional method), viability, and acrosome integrity (under fluorescence microscope following LIVE/DEAD or CTC staining, respectively). Statistical analyses of results from 5 replicated trials were performed by ANOVA with a Bonferroni/Dunn post hoc test (significance; P < 0.05). The extender supplemented with 100 mM trehalose exhibited significantly higher acrosomal integrity (41.6%) compared with other extenders (P < 0.05, n = 5; Table 1). The trend of motility and viability was higher in 274 mM glycerol (28.0 and 52.9%) and 100 mM trehalose extenders (23.6 and 53.9%), but those were not significant. These results demonstrate that the presence of trehalose at 100 mM during cryopreservation improves the acrosome integrity of boar sperm, without any reduction in viability and motility, after thawing. Table 1.Effect of glycerol and trehalose on post-thaw boar sperm