Effect of lactoferrin on ram sperm motility after cryopreservation

Abstract

Objective The objective of this study was to analyse the differentially abundant proteins caused by freeze–thawing of ram sperm and explore candidate proteins of interest for their ability to improve ram sperm cryopreservation outcomes in vitro. Methods Sperm were from three mature Dorper. Fresh and frozen sperm proteins were extracted, and the differentially abundant proteins were analysed by mass spectrometry. Among these proteins, lactoferrin (LTF) was selected to be added before cryopreservation. Next, sperm samples were diluted in Tris extender, with the addition of 0, 10, 100, 500, and 1,000 μg/mL of LTF. After thawing, sperm quality was evaluated by motility, plasma membrane integrity, mitochondrial activity and reactive oxygen species (ROS). Results Cryopreservation significantly altered the abundance of 40 proteins; the abundance of 16 proteins was increased, while that of 24 proteins was decreased. Next, LTF was added to Tris extender applied to ram sperm. The results showed that sperm motility and plasma membrane integrity were significantly improved (p0.05). Supplementation of the cryoprotective extender with 10 μg/mL LTF led to decreased ROS levels compared with those in the control and other groups (p<0.05). Conclusion The LTF is an important protein during cryopreservation, and the addition of 10 μg/mL LTF to a cryoprotective extender can significantly improve the function of frozen ram sperm.

Keywords

• lactoferrin
• proteome
• ram
• sperm cryopreservation