EN
An excessive generation of reactive oxygen species (ROS) in boar semen leads to a reduced motility and fertilizing ability of spermatozoa. Boar spermatozoa, because of a high content of polyunsaturated fatty acids (PUFAs) in their structure, are highly sensitive to lipid peroxidation (LPO). This process, induced by ROS generation, causes irreversible changes in the conformation and integrity of plasmalemma. The boar’s reproductive system includes a special antioxidant system consisting of enzymatic components and antioxidants of low molecular weight. The most active of antioxidant enzymes present in boar semen is superoxide dismutase (SOD). SOD transforms superoxide anion (O₂˙⁻) into hydrogen peroxide (H₂O₂). Because H₂O₂ can easily diffuse across the membranes, it is most harmful to boar spermatozoa. Given the low content of antioxidants of low molecular weight (e.g. L-gluthatione or L-ergothioneine) and the absence of catalase (CAT) activity in boar semen, there must be other mechanisms responsible for the scavenging of hydrogen peroxide and other ROS. This function is probably accomplished mainly by phospholipid hydroperoxide gluthatione peroxidase (PHGPx), enzymes of tioredoxin (TRX) and peroxiredoxin (PRDX) groups, as well as by paraoxonase type 1 and 2 (PON-1 and PON-2).