The Effect of Salvia Sahendica Ethanolic Extract as Natural Antioxidant on Quality Parameters of Cryopreserved Holstein Bull Sperm

Oxidative stress during freezing-thawing reduces motility, viability, membrane functions, antioxidant capacity and finally sperm fertility. Salvia sahendica has antioxidant properties due to phenolic, flavonoids, phenolic acids and phenolic diterpenes compounds. The purpose of this study was to investigate the effect of Salvia sahendica extract as a natural antioxidant on quality of frozen-thawed Holstein bull sperms. In this study, semen samples were collected from three Holstein bulls twice a week using artificial vagina and ejaculates were pooled in order to eliminate the individual effects of bulls. Different levels of Salvia sahendica ethanol extract (0, 2, 4, 8, 12, 16 and 20 ml in dl diluent solution) (which determined based on previous tests) were added to diluents based on egg yolk-citrate. Following cooling and equilibration stage of semen samples, the samples were exposed to nitrogen vapor to be frozen and stored in liquid nitrogen until evaluation. Motility, viability, membrane integrity and the lipid peroxidation parameters of the samples were evaluated after thawing. The results of evaluation showed that, the addition of 2 and 4 ml/dl of Salvia sahendica extract improved motility parameters significantly and addition of 4 ml/dl extract improved viability and plasma membrane integrity of sperms significantly process compared to the control group following freeze-thawing process (P <0.05). Addition of 4 ml/dl extract reduced malondialdehyde concentrations compared to the other groups, however, the differences were not statistically significant. Also, addition of 16 and 20 ml/dl extract had a significantly negative effect on all evaluated traits (P<0.05).