The effect of the natural antioxidants catalase and epigallocatechin added after thawing on the quality of dromedary camel spermatozoa

Sammanfattning: The objective of this study was to evaluate the effect of adding two natural antioxidants (Catalase and Epigallocatechin) to the thawing media on the quality of cryopreserved dromedary camel spermatozoa post-thaw. Also, an indirect measure of ROS production was performed by measuring malondialdehyde (MDA) production (a product of oxidative damage) post-thaw. Ejaculates from 6 adult dromedary camel males (3 ejaculates/male) were included in this study. Ejaculates were obtained using an artificial vagina, frozen in liquid nitrogen vapour (1 cm above the liquid) for 15 min and then plunged into liquid nitrogen for storage. Samples were thawed at 60 ºC for 10 s. Semen evaluation was performed immediately after thawing and 3 aliquots were prepared: control, catalase and epigallocatechin. Semen samples where then evaluated for total motility, progressive motility, kinematics (Computer Assisted Sperm Analysis, CASA), acrosome integrity and membrane integrity at 1.5 and 3h post-thaw. The MDA concentration was measured 3 hours after thawing in the different treatments. Significantly (p<0.05) better values were obtained for the catalase group compared to the epigallocatechin or control groups for total motility (TM) and progressive motility (PM) and some kinematic parameters. None of the treatments showed any significant effect on vitality (VIT) or acrosome damage (AD) after thawing. For MDA production 3h after thawing, no significant effect could be demonstrated for the different treatments and no significant male effect was found. A significant difference was found between males regarding TM, PM and some kinematic parameters, as well as for VIT and AD after thawing. In conclusion, according to this study, addition of catalase to the thawing media can prove beneficial for the survival of dromedary camel sperm following cryopreservation by improving post-thaw sperm quality. The beneficial effects of addition of antioxidants in the cryopreservation media suggest that ROS are likely to be important contributors to the reduced viability of spermatozoa following cryopreservation.