Long term incubation resilience of post-thaw ram semen diluted with lecithin-based extender supplemented with bovine serum albumin

Abstract

The objective of the study was to determine the optimum concentration of BSA in lecithin-based extender for post-thawing quality and incubation resilience (0 h, 6 h and 10 h) of ram sperm. Ejaculates were collected from five rams via electro ejaculation. Ejaculates were mixed to obtain pooled semen. Then, pooled semen was diluted with soybean lecithin-based extender without BSA (control) or supplemented with different concentrations of BSA (2.5 mg/mL, 5 mg/mL, 7.5 mg/mL and 10 mg/mL), at a final concentration of 150x106 spermatozoon/mL. Sperm motility, plasma membrane functional integrity (HOST), mitochondrial activity (rhodamine123), capacitation status (CTC), and DNA integrity (TUNEL) were evaluated. At the 10h incubation, motility, plasma membrane functional integrity and mitochondrial function were better preserved in the BSA5 group compared to the control group. It was determined that high doses of BSA (5 mg/mL, 7.5 mg/mL and 10 mg/mL) affected acrosome reaction. The highest acrosome reaction rates were obtained in BSA10 groups in 6 h and 10 h incubation (P<0.05). TUNEL assay demonstrated that there were no differences among groups for DNA fragmentation at post-thaw and during incubation periods. The study shows that BSA supplemented extenders may have beneficial effect on ram semen parameters at 0 h, 6 h and 10 h of incubation. The results of the present study demonstrated a remarkable advantage of using 5 mg/mL of BSA in 1% lecithin-based extender.

Keywords

• bovine serum albumin
• cryopreservation
• incubation resilience
• ram spermatozoa