Effect of glutathione in extender on the freezability of sahiwal bull spermatozoa

This study was designed to evaluate the effect of glutathione addition in tris-citric acid extender on the freezability of sahiwal bull spermatozoa. semen was collected from three sahiwal bulls of similar age group with artificial vagina (42°c) for three weeks (replicates). qualifying semen ejaculates were pooled,split into three aliquots and diluted in tris-citric extender containing 0.0 (control),0.5 and 1.0mm glutathione. extended semen was cooled to 4°c in 2 hours and equilibrated for 4 hours at 4°c. after equilibration,semen was filled in french straws (0.5 ml) at 4°c,kept over liquid nitrogen vapours (5cm) for 10 min and then plunged in the liquid nitrogen for storage. semen was thawed after 24 hours of cryopreservation at 37°c for 30 seconds. sperm motility,viability,plasma membrane integrity and normal apical ridge were assessed after thawing. highest (p < 0.05) sperm progressive motility,plasma membrane integrity,viability and acrosomal integrity of sahiwal bull spermatozoa were observed in extender containing glutathione 0.5mm. however,glutathione supplementation greater than 0.5mm was not beneficial for any of semen quality parameters. in conclusion,glutathione addition (0.5mm) in extender improves the post-thaw quality of sahiwal bull spermatozoa. © copyright 2014 zoological society of pakistan.