First pregnancies in jennies with vitrified donkey semen using a new warming method.

This research investigates a new method for warming vitrified donkey sperm, comparing its effects on uterine inflammation and fertility with traditional freezing methods. The study found the optimal conditions for sperm motility, and that using vitrified sperm could reduce uterine inflammation and increase chances of successful pregnancy.

Warming Technique Development and Sperm Quality Assessment

• In the first experiment, the researchers vitrified donkey semen using straws. They then warmed the semen in 3 ml of extender fluid or in a water bath at three different temperature/time combinations: 37 °C for 30 seconds, 43 °C for 10 seconds, and 60 °C for 5 seconds.
• The quality of the sperm post-warming was assessed by testing motility, the integrity of the plasma and acrosome membranes, and DNA integrity, comparing the results across the different treatments.
• The researchers found no meaningful difference in sperm quality between specimens warmed in extender fluid versus those warmed in a water bath. However, sperm warmed at 43 °C for 10 seconds displayed better total and progressive motility compared to the slower/less warm conditions.

Fertility Trials with Vitrified and Frozen Semen

• In the second experiment, jennies (female donkeys) were artificially inseminated twice using either vitrified or conventionally frozen semen, with two cycles per jenny.
• The researchers measured the resulting pregnancy rates and the uterine inflammatory response, specifically the concentration of polymorphonuclear neutrophils (PMN), in the jennies after the artificial inseminations.
• No notable differences were found in PMN concentration between inseminations with vitrified or frozen semen. However, the PMN concentration decreased more swiftly with the use of vitrified semen.
• While pregnancy rates were higher with vitrified (22%) than with frozen semen (10%), this difference was not statistically significant.

Conclusion

• The findings suggest that donkey sperm vitrified in straws can be effectively warmed in a water bath at 43 °C for 10 seconds. This method seems to reduce the uterine inflammatory response compared to conventional freezing methods and could potentially enhance pregnancy outcomes in jennies.
• The successful use of vitrified semen in these trials points to its potential as an alternative to traditionally frozen semen in AI procedures with jennies.