hrvatski

Utjecaj mikroklimatskih čimbenika na kakvoću i antioksidativna svojstva sjemena rasplodnih bikova

Taking into account that reproduction quality depends on animal age and climate conditions and that oxidative stress has been reported to be a common cause of infertility, the objective of this study was to monitor indicators of oxidative stress and antioxidant protection during four seasonal periods in service bulls of various age to get better insight into the significance of these factors upon evaluating service bull semen. The research was conducted over a year on 19 Simmental service bulls. Animals were divided into two groups according to age ; group I consisted of younger bulls aged two to four years (n=9), and group II was comprised of older bulls between five to ten years of age (n=10). Semen samples were obtained during one week in every seasonal period and blood samples for biochemical analysis were collected by jugular venipuncture immediately prior to ejaculate collection. The activity of total glutathione peroxidase (T-GSH-Px), selenium-dependent glutathione peroxidase (Se-GSH-Px) and selenium-independent glutathione peroxidase (non-Se-GSH-Px) together with the intensity of lipid peroxidation (TBARS concentration) and oxidative protein damage (PCC concentration) were measured in semen plasma. In samples of spermatozoa and blood serum, the activity of Se-GSH-Px and TBARS and PCC concentrations were determined. Older service bulls had significantly higher ejaculate volume in summer in comparison to younger bulls, whereas the number of spermatozoa and progressive motility percentage did not significantly vary with age. Younger animals had lower progressive motility percentage during summer than in spring, with more intensive oxidative processes observed in semen plasma (TBARS) and spermatozoa (TBARS and PCC). Based on the results presented here, it can be concluded that younger bulls are more sensitive to elevated ambient temperatures during the summer, when intensified pro-oxidative processes in semen plasma and spermatozoa eventually led to decreased sperm progressive motility with consequential semen quality deterioration.

rasplodni bikovi; oksidativni stres; antioksidansi; sjemena plazma; godišnje doba

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