Supplemental Glutathione Improves Post-Thaw Quality of Holstein Bulls Sperm in a Nanomicelle based Extender

Adding antioxidants to semen extenders could reduce post-thaw sperm damages. Glutathione is an important intracellular antioxidant that has free radicals scavenging properties and multiple effects on DNA and protein synthesis. In the present study, effects different levels of reduced glutathione (GSH) containing 0 (control), 1.0, 2.5, or 5.0 mM in a nanomicelle-based extender on post-thaw quality of bovine sperm were investigated. Initially, lecithin was added to a tris-based extender containing GSH. The mixture was then emulsified by slowly shaking and sonification so that nano size of particles was obtained. Thirty-six ejaculates from six Holstein bulls were used. The post-thaw quality parameters including computer-assisted sperm analysis of motility, plasma membrane functionality, membrane integrity, acrosome integrity, morphology and level of apoptosis were measured. Compared to the control medium, the total motility and membrane integrity were significantly better in samples containing 2.5 mM GSH (67.3±1.2% vs. 73±1.2% and 71.3±1.5% vs. 77.6±1.5%, respectively). The extender supplemented with 2.5 mM GSH had the highest percentage of viable sperm during apoptotic test. In conclusion, supplementation of lecithin nanomicelle-based extender with 2.5 mM GSH reduced damages to bovine sperm during cryopreservation.