engleski

Seasonal Variations in Semen Antioxidants of Simmental Bulls

Many environmental and physiological factors induce oxidative stress, thus the objective of the present study was to examine seasonal variations of antioxidant enzymes and lipids oxidation in bull spermatozoa and seminal plasma. Semen was collected by use of sterile artificial vagina from nine breeding Simmental bulls aged between 2.5 and 7.2 years (5.1±0.6 yr ; mean±SE) once in summer and once in winter. In the spermatozoa and seminal plasma activities of total superoxide dismutase (TSOD), glutathione peroxidase (GSH-Px), catalase and lipid peroxides concentrations (LPO) were determined. Spermatozoa TSOD activity in summer was significantly higher from the values recorded in winter (6434±899 U/g protein ; vs. 3839±297 U/g protein). GSH-Px activity (202±19 U/g protein vs. 343±27 U/g protein) and LPO concentration (9.4±2.4 μmol/g lipids vs. 22.0±2.9 μmol/g lipids) in bull spermatozoa were significantly lower in summer as compared with winter values of these parameters. No catalase activity was detected in spermatozoa. Seminal plasma TSOD activity was significantly higher in summer compared with that in winter (2939±171 U/L ; vs. 2381±129 U/L). Activities of GSH-Px and catalase, and LPO concentration in bull seminal plasma showed no significant seasonal variation. In this study, positive correlation was recorded between seminal plasma catalase and TSOD, and activity of catalase was negatively correlated with GSH-Px. Activity of TSOD and pattern of its changes, probably as a result of higher environmental temperatures in summer, might be a good predictive tool for evaluation of semen quality.

semen; Simmental bulls; antioxidants; season

nije evidentirano