Effects of centrifugation and cholesterol-loaded with cyclodextrin in the soybean lecithin -based extender on the quality of the post-thaw sperm of Ghezel ram

Abstract

When using frozen-thawed semen, maintaining the motility and viability of ram sperm is important for achieving high pregnancy rates. The goal of this research was to clearly elucidate the effects of centrifugation and cholesterol-loaded cyclodextrin (CLC) in a soy lecithin-based extender on post-thaw ram sperm quality. Sperm samples were collected from 5 Ghezel rams with the age of 4-5 years for 3 weeks. After the initial assessment, the approved semen samples were combined and divided into 8 equal parts. Four samples were combined at 30˚C and the seminal plasma was then removed by centrifugation. The semen from the other four samples was not centrifuged and was diluted with Tris buffer plus different concentrations of CLC (0, 0.75, 1.5 and 3 mg/ 1.2×108 spermatozoa) and 7% glycerol, similar to the first group. The samples were then cooled to 5˚C and frozen in 0.25 ml straws. After thawing, total motility (TM) and progressive motility (PM), straight line velocity (VSL), curvilinear velocity (VCL), beat cross frequency (BCF), total antioxidant capacity (TAC), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione peroxidase (GPX), the integrity of the acrosome membrane and the integrity of the plasma membrane were significantly (pp<0.05) higher in the group without centrifugation than in the centrifugation group. Overall, the results suggested that addition of 1.5 mg CLC improves most of the sperm parameters measured in vitro in comparison to other groups.

Keywords

• cyclodextrin
• sperm
• ram
• centrifugation
• soybean lecithin
• freeze-thawing