Effects of Three Different Diluents on Quality of Boar Semen Stored at 17°C

To investigate the effects of different diluents on the quality of the boar semen stored at 17°C, and assess the relationship between sperm motility and the relative levels of enzymes, three commercial diluents (Diluent I, Diluent II and Diluent III) and three boar breed semens (Yorkshire, Landrace and Duroc) were utilized. The sperm motility, effective survival time, survival index, catalase (CAT), the total anti-oxidative capacity (T-AOC) and malondialdehyde (MDA) levels were evaluated. The results showed that there were significant interaction effects between diluents and breeds on the boar sperm motility (P<0.001), survival time (P<0.001), CAT levels (P<0.001) and T-AOC levels (P<0.001), but neither effects nor interaction effects between diluents and breeds on survival index (P>0.05). All of the parameters varied significantly with the increase of the storage time (P<0.001). The survival time increased 12.9% in Yorkshire boar semen diluted with Diluent III than with Diluent II, while the survival time increased 6.6% in Landrace boar semen diluted with Diluent II than with Diluent III. Both CAT and T-AOC levels were significantly positive correlated with sperm motility in all the three boar breeds (P<0.001), while MDA levels were significantly negative correlated with sperm motility (P<0.001). These results indicated that Diluent III and Diluent II were the optimal commercial diluents for Yorkshire and Landrace boar semen stored at 17°C, respectively.