Effect of different catalase concentrations on chilled Holstein bull’s semen

Abstract

Abstract This study aimed to investigate the effect of catalase (CAT)concentrations on the Holstein bull semen diluted in egg yolk-citrate (EYC) extender and stored at 5oC. Characteristics evaluated were progressive motility (PM), plasma membrane integrity (PMI), viability and total abnormal sperm (TAS) percentages. Six ejaculates (each considered a replicate) were collected from a bull using an artificial vagina method twice a week for 3 weeks. An aliquot of the semen from each ejaculate was evaluated pre-extension. The remainder semen was extended in EYC containing 0 U/ml of CAT (T1), 50 U/ml (T2), 100 U/ml (T3), 150 U/ml (T4), 200 U/ml (T5), 250 U/ml (T6), and 300 U/ml (T7) of CAT, and stored at 5oC. Characteristics were evaluated every day until viability reached zero. The addition of CAT into EYC improved viability, PM, PMI and decreased the total abnormal sperm cells. Non-significant differences between T1 and other treatments were observed concerning PM and PMI, but significant (P< 0.05) differencesexisted between T1 and other treatments for viability, and TAS. Based on this study, the addition of catalase at an optimal concentration of 200U/ml to the chilled bull semen diluted in EYC extender and stored at 5oC was advantageous in improving the semen quality of Holstein bulls. This semen can be satisfactorily used in artificial insemination programs a week after its collection. Key words: bull, catalase, extender, semen qualitycharacteristics