Effect of the pH pre-adjustment in the freezing extender on post-thaw boar sperm quality

Abstract

Background: During freezing the selective precipitation of substances in the medium may provoke a pH shift and lead to sperm damage. Objective: To study the effect of the pH preadjustment in the freezing extender on post-thaw boar sperm quality. Methods: A total of 15 ejaculates from different boars were obtained and divided into six aliquots prior to a standard straw cryopreservation in freezing extender (lactose-egg yolk-glycerol-Orvus ES Paste) with different pH. After thawing, sperm quality (plasma membrane integrity, motility and acrosome status) were assessed at 30 and 90 minutes of post-thaw incubation at 37ºC. Results: When the boar sperm were frozen in a freezing media with pH basic, and particularly at pH 8, it had higher post-thaw sperm quality. Conclusion: The pre-adjustment at pH 8 of the freezing extender (lactose-egg yolk-glycerol-Orvus ES Paste) is able to improve the post-thaw boar sperm quality.