Effect of medium variations (zinc supplementation during oocyte maturation, perifertilization pH, and embryo culture protein source) on equine embryo development after intracytoplasmic sperm injection.

This study examines the impact of different conditions on the development of horse embryos created via intracytoplasmic sperm injection (ICSI), such as zinc supplementation, pH during fertilization, and protein source.

Context of the Research

• The research presented aims to better understand factors influencing in vitro production of embryos in horses.
• The procedures evaluated in the study include the intracytoplasmic sperm injection (ICSI) method of equine oocyte fertilization and how it responds to variations in medium components, such as protein source, perifertilization pH, and zinc supplementation.

Details of Experimental Procedure

• The researchers conducted prospective studies to make more significant observations.
• The study consisted of three distinct experiments focusing on the effects of protein source in embryo culture medium, zinc supplementation during in vitro maturation (IVM), and perifertilization pH levels.

Key Findings and Conclusion

• In the first experiment, it was found that utilizing 10% fetal bovine serum in the embryo culture medium resulted in a higher blastocyst rate compared to a combination of 3% fetal bovine serum, 3% equine preovulatory follicular fluid, and 4% human serum substitute.
• In the second experiment, the study evaluated the impact of different zinc supplementation levels during IVM and discovered no substantial difference in cleavage or blastocyst development rates. But, blastocysts’ portion that developed on Day 7 was significantly higher for the added-zinc treatments.
• In the third experiment, a high-pH medium was used for sperm preparation and for the first two hours of incubation of the injected oocytes after ICSI. The cleavage rate remained unchanged, but no blastocysts developed, indicating an unfavorable condition for equine embryo development.
• The study’s findings suggest the importance of carefully considering these procedural elements when producing equine embryos in vitro, and they add to the general understanding of equine reproduction science and this particular part of animal cloning advancement.