Boar sperm quality in relation to presence of sp32-like protein in spermatozoa - preliminary studies

The aim of the study was to analyse sperm proteomes of ejaculates from Polish Large White (PLW) and Polish Landrace (PL) boars and to identify differences which putatively influence semen quality. Spermatozoa protein profiles were analysed by electrophoretic methods followed by selected techniques to evaluate semen quality on the following factors: sperm motility, lipid peroxidation levels (MDA production), ATP content, activities of superoxide dismutase (SOD) and catalase (CAT), total antioxidant status (TAS), and total oxidant status (TOS) of seminal plasma. A protein with an estimated molecular weight of 30 kDa was found in spermatozoa of selected ejaculates. Mass spectrometry demonstrated that this polypeptide is most similar to proacrosin binding protein (sp32). The presence of the protein was more frequently observed in sperm extracts obtained in spring-summer period. Ejaculates containing sp32-like protein demonstrated significantly higher spermatozoa motility, lower inhibition of MDA production by seminal plasma, and higher SOD activity in seminal plasma. Boar semen which included sp32-like protein also demonstrated lower ATP levels in spermatozoa as well as higher TAS and lower TOS of seminal plasma, though the differences were not statistically significant. Ejaculates from PLW boars, with sp32-like protein present in sperm, were characterised by significantly higher sperm motility, lower ATP content in spermatozoa, and higher TAS of seminal plasma. The diminished parameters of semen quality were observed in ejaculates from PL boars that also contained the discussed protein, but the differences were not statistically significant. These findings suggest that the presence of sp32-like protein in boar spermatozoa could influence semen quality