Effects of Leucosporidium Ice-binding Protein on the Cryopreservation of Boar Sperm

다국어 초록 (Multilingual Abstract)

This study was performed to evaluate effects of Leucosporidium ice-binding protein (LeIBP) supplementation on boar (Duroc) sperm freezing. The collected semen was diluted (1.5×10⁸ /mL) in lactose egg yolk (LEY) and cooled at 5°C for 3 h. The cooled semen was then diluted (1×10⁸ /mL) in LeIBP containing LEY with 9% glycerol and maintained at 5°C for 30 min. The semen was divided into six experimental groups (control, 0.001, 0.005, 0.01, 0.05, and 0.1 mg/mL of LeIBP). The straws were stayed above the liquid nitrogen (LN2) vapors for 20 minutes and then plunged into LN2. After thawing, sperm parameters such as motility, viability, and acrosome integrity, intracellular reactive oxygen species (ROS), apoptosis, and undetected lipid peroxidation were determined. Computer assisted sperm analysis was used for sperm parameters and flowcytometry was performed to acrosome integrity (FITC-PSA/PI), ROS (DCFHDA/ PI), lipid peroxidation (BODIPY C11/PI), and apoptosis (Annexin V/PI), respectively. The differences were not in sperm motility, but in viability of 0.05 and 0.1 mg/mL groups compared to control (p<0.05). Higher acrosome integrity was observed in LeIBP groups compared to control (p<0.05), except for 0.001 group. Both ROS and lipid peroxidation level were lower in all LeIBP groups than that of control (p<0.05). Furthermore, lower apoptosis rate was observed in both 0.005 and 0.1 LeIBP groups compared to control (p<0.05). It can be postulated that a supplementation of LeIBP in boar sperm freezing extender is an effective method to increase the sperm qualities after cryopreservation.