Effect of seminal plasma on the redox state of cryopreserved stallion semen

Objective. Determine the effect of seminal plasma on the generation of reactive oxygen species (ROS) and lipid peroxidation of cryopreserved stallion semen, and its association with semen quality parameters. Materials and methods. The semen of five stallions of Colombian creole breed (two ejaculates each) was cryopreserved by a rapid freezing protocol, using a milk-egg yolk extender supplemented with 0%, 10% and 20% of equine seminal plasma. The samples of fresh and cryopreserved semen were evaluated for ROS generation and lipid peroxidation by spectrofluorimetry, and semen quality parameters of progressive motility, vitality and membrane integrity using phase contrast microscopy. Mixed models were adjusted for statistical, regression, and correlation analysis. Results. Post-thaw averages of progressive motility, vitality and integrity of membrane of 37.8% ± 20.2, 50.6% ± 14.6 and 37.8 ± 15.5%, respectively were found. For fresh and cryopreserved semen supplemented with 0%, 10% and 20% of seminal plasma, the averages of ROS production (RFU) were 13.34 ± 10.7, 16.15 ± 13.5, 17.32 ± 16 and 22.98 ± 19.4, respectively; showing a statistically significant increase (p?0.05) of ROS production by effect of cryopreservation and seminal plasma supplementation. The averages of lipid peroxidation (nmolMDA / ml) for these same treatments were 0.41 ± 0.25, 0.72 ± 0.37, 0.51 ± 0.29 and 0.47 ± 0.26, respectively; showing a significant decrease (p?0.05) of lipid peroxidation of semen supplemented with 10% and 20% of seminal plasma compared to unsupplemented semen (0%). Conclusions. Seminal plasma reduces lipid peroxidation of stallion cryopreserved semen.