The effects of mitoquinol mesylate on post-thaw characteristics and fertilizing ability of rooster semen cryopreserved in the Beltsville medium

Cryopreservation of rooster semen is a reproductive technology carried out to boost genetic gain and productivity in commercial flocks of chicken. However, semen freezing significantly reduces the quality and fertilizing potential of spermatozoa. This study examined cryoprotective effects of the mitochondria-targeted antioxidant mitoquinol mesylate added to the freezing extender by assessing post-thaw characteristics of rooster sperm. Semen samples were diluted in the Beltsville extender supplemented with 0, 1, 10, 100 or 1000 nM of mitoquinol mesylate. Following the thawing of cryopreserved semen doses, we evaluated the following sperm parameters: motility and morphology, membrane integrity and mitochondrial function, acrosome integrity, apoptosis status, lipid peroxidation, DNA fragmentation, reactive oxygen species (ROS) accumulation, epigenetic patterns (DNA methylation and histone modifications), and fertilizing ability. Semen diluted in extenders containing 10 or 100 nM of mitoquinol mesylate significantly exceeded all other groups of frozen-thawed semen samples in sperm motility, average path velocity as well as membrane/acrosome integrity, mitochondrial function indices and DNA/histone modification. Moreover, the addition of 10 and 100 nM of mitoquinol mesylate significantly reduced lipid peroxidation, apoptosis rate, DNA fragmentation and ROS concentrations compared with all other dilutions and was associated with a higher (P ≤ 0.05) fertilization rate compared with a non-supplemented control group, albeit it was still significantly lower compared with that obtained using fresh semen. It can be, however, concluded that mitoquinol mesylate significantly improved an array of quality parameters and fertilizing potential of rooster semen, and hence can be recommended for use as a diluent additive in semen cryopreservation procedures employed in commercial poultry operations.