The effect of cysteine and glutathione on sperm and oxidative stress parameters of post-thawed bull semen

The aim of this study was to determine the effects of antioxidants such as reduced glutathione (GSH) and cysteine in Laiciphose® extender on semen parameters, fertilizing ability, Lipid Peroxidation (LPO) and GPx (Glutathione peroxidise) activity of post-thawed bull semen. In the study, totally 54 ejaculates of three bulls were used. Five groups, namely; GSH (0.5 and 2 mM), cysteine (5 and 10 mM) and control group were conducted to test the antioxidants in Laiciphose®. Insemination doses were processed so that each 0.25 mL straw contained 15×106 sperm. The addition of antioxidants did not provide any significant effect on the percentages of post-thaw sperm morphology (sacrosome and total abnormalities), subjective, CASA and progressive motilities, as well as sperm motility characteristics (VAP, VSL, VCL, LIN and ALH), compared to the control groups (p>0.05). GSH 0.5 mM (55.5±7.38%) and cysteine 10 mM (48±5.65%) gave rise to lower rates of DNA damage, compared to control (p<0.05). With respect to fertility results based on 59 days non-returns, the supplementation of antioxidants did not present significant differences (p>0.05). For MDA level, cysteine at 10 mM dose gave the highest level (4.99±0.44 nmol L-1(p<0.001). GPX activity was demonstrated to be higher level upon the addition of 5 mM cysteine when compared to the other groups (p<0.05). © Medwell Journals, 2010.