Supplementation of the semen extender with antioxidants did not produce any significant effect on CASA and progressive motilities and sperm motility characteristics, in comparison to the control group (P>. 0.05).For sperm acrosome and total abnormalities, TCM-199 supplemented with cysteine (2.60. ±. 0.24% and 4.80. ±. 0.20%), glutamine (2.80. ±. 0.20% and 6.40. ±. 0.40%), carnitine (2.60. ±. 0.24% and 6.00. ±. 0.63%) and methionine (3.40. ±. 0.51% and 9.20. ±. 0.86%) at doses of 2. mM provided a better protective effect, compared to that of the controls (8.00. ±. 0.44 and 15.60. ±. 1.895). As regards sperm membrane integrity, supplementation with 2. mM of glutamine and methionine (56.00. ±. 1.70% and 62.40. ±. 1.78%, respectively) resulted in higher rates, when compared to the control group (41.40. ±. 4.74%). According to the results of the COMET assay, only the use of TCM-199 supplemented with 2. mM of cysteine reduced DNA damage and resulted in percentages of sperm with damaged DNA (2.17. ±. 0.18%) lower than those of the control group (3.16. ±. 0.32%) (P<. 0.001). For pregnancy rates, there were no significant differences among the extender groups (P>. 0.05). © 2014.