The Effects of X-Ray Irradiation on Bovine Sperm Quality Indicators After Freezing and Thawing

This study was conducted to determine the suitable dose of x-ray irradiation on bovine sperm quality indicators after freezing and thawing. Sperm samples in liquid nitrogen were x-ray irradiated at doses of zero, 0.3, 0.6, 0.9, and 1.2 Gy. The results showed that irradiation influenced (P 0.05) motility and viability of sperms. The semen malondialdehyde concentration had no significant differences among treatments. Based on the comet assay result, DNA strand breaks parameters had no significant differences with the control group, except at a dose of 1.2 Gy. Based on flow cytometry results, sperm percentage with high activity of mitochondrial membrane was increased and those with low activity decreased (P 0.05). The HOST test showed that sperm percentage with plasma membrane integrity in irradiated samples at a dose of 0.3 Gy had no significant difference compared to the control group, but sperm percentage with intact plasma membrane was higher in the sample irradiated at doses of 0.6 and 0.9 Gy. Irradiation at a dose of 0.9 Gy increased sperm with the intact plasma membrane. Doses lower than 1.2 Gy did not affect acrosome integrity, but 1.2 Gy x-ray irradiation decreased sperm having intact acrosome (P 0.05). Based on these results, x-ray irradiation at a dose of 0.9 Gy could increase the mitochondrial membrane activity and enhance the motility and viability of sperms after thawing without a negative effect on semen and sperm quality while x-ray irradiation at a dose of 1.2 or more Gy deteriorates semen quality.