Improvement of liquid stored boar semen quality by removing low molecular weight proteins and supplementation with α-tocopherol.

Seminal plasma contains low-molecular weight components that can exert a harmful effect on sperm function. We have evaluated the effects of removing low-molecular weight components from seminal plasma and adding α-tocopherol on boar semen quality after 72h of liquid storage. Semen was evaluated on the basis of motility, morphology, acrosome integrity, plasma membrane modifications, mitochondrial activity, DNA fragmentation and lipid peroxidation. Thiobarbituric acid reactive substances (TBARS), 8-isoprostane, and antioxidant status (total antioxidant capacity (TAC) and superoxide dismutase activity (SOD)) were measured in seminal plasma. Removal of low-molecular weight components from seminal plasma, together with the addition of α-tocopherol, kept the lipid peroxidation and mitochondrial activity and DNA fragmentation at the same level as in native semen samples. Dialysing semen and adding 200μM of α-tocopherol led to higher progressive motility, a higher proportion of morphologically normal spermatozoa and a significantly lower level of acrosomal reacted spermatozoa compared to non-dialyzed semen samples after 72h of storage. In conclusion, liquid stored boar semen was better preserved, and oxidative stress in the semen was reduced when semen was dialyzed and α-tocopherol was added prior to storage.