Hydroxytyrosol effectively improves the quality of pig sperm at room temperature

Background: Artificial insemination technology is the production technology used in more than 99% of the world's pig farms. Preservation of semen is mainly conducted at room temperature (17°C), during which the accumulation of reactive oxygen species (ROS). In our research, by adding different concentrations of hydroxytyrosol to the diluent during the storage of boar semen at 17°C, we compared them with the traditional diluent to study the cumulative amount of ROS, the extent of membrane damage, the sperm acrosome integrity, the activity of antioxidant enzymes, and other indicators to evaluate the effect of hydroxytyrosol on the changes of active oxygen and sperm quality during storage. After we determined the optimal amount of hydroxytyrosol in the diluent, Proteomics was used to monitor difference in sperm protein expression between the control group and the addition of 120 μmol/L hydroxytyrosol (optimum concentration) group after three days’ storage. Ultimately, we selected the control group and the addition of 120 μmol/L hydroxytyrosol group to test the effect of artificial insemination.Results: During storage of pig semen at room temperature, the sperm quality of the hydroxytyrosol-treated group was significantly improved (P < 0.05). Besides, its antioxidant capacity was also significantly improved (P < 0.05). Proteomics sequencing analysis proved that the addition of hydroxytyrosol treatment group has potential value in improving sperm cell quality. The significant increase in sow pregnancy rate and the increase in piglet birth weight also confirmed that sperm quality during storage can be of vital importance in actual production (P < 0.05).Conclusions: Based on our results, we demonstrated that the addition of hydroxytyrosol to the diluent can not only improve the quality of pig sperm, but also has an irreplaceable role in improving the efficiency of artificial insemination.