Effects of Caffeine on the Cryopreservation of Boar Semen and Optimizationg of Freezing and Thawing Protocal of Rapid Freezing Techniques

The aim of this study was to investigate the effect of supplementation of caffeine in freezing extender on frozen-thawed semen quality.Optimize freezing and thawing protocol in 0.5 mL straws.Supplementation of caffeine directly into preliminary design freezing extender,the concentration of caffeine was 0,0.2,0.4,0.6 mg/mL,determined the best concentration of caffeine.Then compared with the traditional TCG extender and the AndrohepCryoGuardTM extender,comparison of three different freezing curves on the frozen-thawed sperm quality.The frozen sperm samples were thawed by warming them at 37 ℃ water bath for 30 s and 50 ℃ water bath for 13 s.The results showed that there was a significantly higher percentage of progressive motility,membrane integrity and acrosome integrity in caffeine supplemented groups than control group(P0.05),the best concentration was 0.2 mg/mL.The preliminary design was better than the TCG(P0.05),but it had a significant variance with AndrohepCryoGuardTM extender(P0.05).Three different freezing curve had different influence on sperm quality parameters.Freezing curve A had a higher percentages of TMS,PMI and NAR of spermatozoa than B and C(P0.05),thawed at 50 ℃ for 13 s was better than 38 ℃ for 30 s.