The aim of this study was to determine the effect of low levels of glutathione on post-thawed buck sperm quality. In this experiment, different concentrations of glutathione [0 (LG-0), 0.5 (LG-0.5), 1 (LG-1), 1.5 (LG-1.5), and 2 (LG-2) mM] were added in a soybean lecithin-based extender. A total of 16 ejaculates from four bucks were collected and pooled. Each pooled sample was divided into five equal parts and each part was diluted by one of the above mentioned groups. After freeze-thawing process, motility and velocity, plasma membrane integrity and functionality, and apoptosis features of spermatozoa were evaluated. The results of this experiment showed that total motility (50.75 ± 2.33), plasma membrane integrity (55.75 ± 3.01) and functionality (46.75 ± 2.79) were higher in LG-1 extender compared to other extenders (P<0.05). The percentage of live spermatozoa (53.23 ± 3.26) was higher in LG-1 extender compared to other extenders, with the exception of LG-1.5 extender (P<0.05). Also, the percentage of late apoptotic spermatozoa (21.33 ± 1.63) was lower in LG-1 extender compared to other extenders (P<0.05). In conclusion, our results showed that GL-1 extender resulted in higher post-thawed buck sperm quality compared to other extenders.
