Effect of different manual puncture methods on donkey embryo before vitrification.

This research paper evaluates how different puncture methods affect the viability and pregnancy rates of frozen and then thawed donkey embryos. The study is aimed at improving the efficiency of donkey embryo cryopreservation, a technology helpful for the preservation and transfer of recovered embryos with superior genetic traits.

Purpose and Methodology

• The study’s objective was to optimize the embryo cryopreservation method in donkeys, which is currently known to be inefficient. It sought to investigate the impacts of various manual puncture techniques on the survivability and pregnancy rates of donkey embryos post-vitrification (a freezing process) and thawing.
• The researchers amassed a total of 117 donkey embryos on day 7-8 post-ovulation, which were then divided into four random groups: Control, VG, VM, and VMP. Each group underwent different treatment procedures before vitrification.

Experiment Groups and Results

• The ‘Control’ group consisted of 28 embryos that were not subjected to any punctures or cryopreservation, serving as a baseline for the study.
• The ‘VG’ group had 29 embryos that were manually punctured using a 29G needle.
• The ‘VM’ group also had 29 embryos that were manually punctured using a microneedle with a sharp tip of less than 10 micrometers.
• The ‘VMP’ group consisted of 31 embryos punctured with a microneedle and then vitrified using a different solution containing proline.
• Each batch of fresh and vitrified-thawed embryos was incubated for 3 hours before being transferred.
• The results indicated higher embryo recovery rates on day 7.5 and 8 compared to day 7.
• The percentages of dead cells post-incubation in VM and VMP groups were lower than the VG group, although all were higher than the Control group.
• The pregnancy rate in the VG group was lower than in the Control, VM, and VMP groups. No pregnancies resulted from any VG embryos that were ≤650 μm in diameter, unlike the VM and VMP groups. The pregnancy rates among all vitrification groups remained consistent when embryos were >650 μm in diameter.

Conclusion

• The study concluded that waiting until day 8 post-ovulation for embryo recovery was more effective. Puncturing embryos using a microneedle caused less damage and resulted in higher pregnancy rates than with 29G needles. Also, the finding suggests that proline could potentially improve donkey embryo cryopreservation techniques.