Agriculture & Food, Volume 6, 2018

Abstract: Oxidative stress during freezing-thawing reduces motility, viability, membrane functions, antioxidant capacity and finally sperm fertility. Mentha piperita L. has antioxidant properties due to phenolic compounds. The aim of current study was to evaluate the effect of Mentha piperita extract as a natural antioxidant on dynamic parameters post-thawed Moghani ram sperm. In this study, four Moghani ram were used for semen collection twice a week by an artificial vagina and ejaculates with same condition were pooled. Different levels of ethanol extract of Mentha piperita L. (0, 2, 4, 8, 12 and 16ml in dL diluents solution) were added to Tris based diluents. Following cooling and freezing of semen samples, they were stored in liquid nitrogen until evaluation. After freezing-thawed, the dynamic parameters were evaluated using CASA system. The results showed that the addition of 4 and 8ml/dl extracts resulted in higher (p < 0.05) percentages of total motility. Addition of 4 ml/dl extract improved progressive motility compared to the control group and high levels of extract groups (P <0.05). The percentages of LIN, STR and VSL were higher (P<0.05) in the extender containing 8 mL/dL extract (54.43±4.42; and 94.20±7.93, respectively). Addition of 4 and 8 mL/dL extract of Mentha piperita L. to the extender significantly (P<0.05) improved VCL and VAP parameters compared to the control and 16 mL/dL extract groups. In conclusion, supplementation of extender with Mentha piperita L. extract improves post-thawed ram sperm motility and velocity parameters in a dose dependent manner.