Glutathione Peroxidase Fortification Improves the Plasma Membrane Intactness, Mitochondrial Status and Antioxidant Potential of Cryopreserved Japanese Quail Semen

Glutathione peroxidase (GPx), a crucial element of anti-oxidative defence, is known to enzymatically ward off lethal free radicals released from redox metabolism within the sperm. However, in vitro semen chilling procedures gravely affect the scavenging capacity of antioxidants to counter reactive oxygen species (ROS) and dismantle the cellular structures. This directs towards the integration of exogenous antioxidants into the semen freezing medium. Japanese quail, not fully exploited yet because of high sensitivity to inbreeding, if propagated via assisted reproduction, could enormously contribute to fulfill the escalating poultry demand. Therefore, the current study aimed at investigating the effect of GPx fortification on the quality, mitochondrial activity, antioxidant potential and lipid peroxidation (LPO) of cryopreserved Japanese quail semen. For this purpose, pooled semen (30 males) was divided and diluted with NaCl extender (1:15) having 5, 10 15 U GPx/mL and control. Samples were cryopreserved and evaluated for the quality and biochemical activity at post-dilution, post-cooling, post-equilibration and post-thaw stages of cryopreservation. The sperm motility (η_p ² = 0.617), plasma membrane integrity (η_p ² = 0.666), viability (η_p ² = 0.691), mitochondrial status (η_p ² = 0.710), total antioxidant potential (η_p ² = 0.674) and free radical scavenging capacity (η_p ² = 0.680) were recorded highest (p < 0.05) in samples containing 5 U GPx/mL compared to other concentrations and control at all the stages of freezing. Moreover, the lowest LPO was recorded in the samples with 5 U GPx/mL followed by 10 U GPx/mL, control and 15 U GPx/mL throughout the stages of cryopreservation. The study concluded that GPx at 5 U/mL maintains the quality and scavenging capacity of cryopreserved Japanese quail semen against ROS accumulation.