Alpha-tocopherol improves biochemical and dynamic parameters in cryopreserved boar semen

Cryopreservation is associated with the production of reactive oxygen species which lead to lipid peroxidation of sperm membranes. The objective was to determine an α-tocopherol concentration capable of improving the quality of cryopreserved porcine semen. Boar spermatozoa frozen with 200, 500 or 1000 μg/mL α-tocopherol were thawed and incubated at 37 °C for 4 h. Routine parameters of semen quality, susceptibility to lipid peroxidation 2-thiobarbituric acid (TBARS) and oxygen uptake were evaluated. Motility was higher (P < 0.05) in samples treated with different concentrations of α-tocopherol up to 2 h of incubation. Viability and acrosome integrity significantly decreased during incubation (no significant differences between treatments). Two hundred micrograms per milliliter α-tocopherol protected spermatozoa against lipid peroxidation during incubation, but 1000 μg/mL failed to protect after 2 h of incubation. There was a negative association between TBARS and motility, suggesting that lipid peroxidation affected sperm motility. Both control and 200 μg/mL α-tocopherol samples preserved the capacity to generate oxidative energy up to 1 h of incubation. The addition of 200 μg/mL α-tocopherol in the semen extender could be useful to preserve boar spermatozoa against the oxidative stress generated by cryopreservation.