Effect of antioxidant supplementation on function and fertility of sex-sorted boar spermatozoa

The goal of this study was to investigate the effects of antioxidant supplementation on the quality of flow cytometrically-sorted boar spermatozoa. The effects of ascorbic acid-2-glucoside (AA-2G) on the sex-sorting process were evaluated using a variety of concentrations. The effects of different antioxidants (AA-2G, l-glutathione, and vitamin E) on the viability and lifespan of boar spermatozoa were also compared during sorting. Furthermore, the effect of AA-2G on acrosome intactness, the capacitation ability of sorted boar spermatozoa and pregnancy efficiency after artificial insemination (AI) at different sorting-to-insemination intervals were examined. Greater (P < 0.05) percentages of motile spermatozoa and acrosome intactness and longer storage time periods were observed in the AA-2G-supplemented group when compared with the other antioxidant-supplemented or control groups. At an AA-2G concentration of 0.068 mg/mL, the motility characteristics (i.e., straightness (STR), velocity according to the average path (VAP), and amplitude of the sperm head lateral displacement (ALH)) of the sex-sorted boar spermatozoa were greater (P < 0.05) than in those treated with other AA-2G concentrations. The capacitation rate of boar spermatozoa in the AA-2G-supplemented group was less (P < 0.05) than that in the control group. After sorting-to-insemination interval of 10 h, the pregnancy rates after AI with boar spermatozoa for the AA-2G-supplemented group were 59.25%, while the control group remains no sufficient quality semen. This study demonstrates that AA-2G supplementation can improve the quality of flow cytometrically sorted boar spermatozoa and that the optimal concentration of AA-2G for sorting is 0.068 mg/mL.