Reactive oxygen species cause damage to mammalian sperm during freezing. Curcumin is a known antioxidant compound against oxidative stress. The aim of this study was to investigate the effects of curcumin in soybean lecithin-based extender on various parameters of sperm motility, and lipid peroxidation of Ghezel ram semen. Sperm samples of 5 adult Ghezel rams were collected for 3 weeks. After the initial assessment, the approved semen samples were pooled and divided into 4 equal parts in the tubes. The semen from the other four tubes was diluted with Tris buffer + different concentrations of curcumin (0, 1, 2 and 3 mM) and 7% glycerol. The results indicated a significant improvement in total motility and other parameters of sperm motility and decreased lipid peroxidation in the 2mM curcumin group after the thawing process compared to other groups (p < 0.05). Generally, the results showed that addition of 2 mM curcumin improved most of the evaluated parameters compared to other groups.
