Inhibition of sperm binding to porcine ova by antibodies to equine zonae pellucidae.

This research examines the impact of specific antibodies on the fertility of horses, suggesting that the presence of these antibodies can lead to reduced or complete infertility in some mares.

Introduction

• The research focuses on evaluating the relationship between the occurrence of specific antibodies, known as antibodies to the zona pellucida, and fertility in mares.
• Zona pellucida is a membrane that surrounds the egg in females of certain species. The antibodies to the zona pellucida are associated with infertility, as they can potentially prevent sperm from binding to the egg.

Methodology

• The researchers collected sera and follicular fluid from mares already identified as having antibodies to the zona pellucida.
• These samples were exposed to porcine ovarian oocytes (pig eggs) before being inseminated with boar sperm.
• A comparison group consisted of mares lacking the antibodies.

Results

• The eggs exposed to the sera with the antibodies showed a dramatic decline in the numbers of sperm able to bind to the eggs’ zonae (the membranes).
• In a broader group of 50 randomly selected mares tested, 2 pregnant mares were found to have the antibodies, one at 60 days and another at 90 days of gestation.
• In three mares previously identified as having the antibodies, the presence of the antibodies varied considerably over a 6-month sampling period.

Conclusions

• The researchers concluded that the presence of antibodies reactive with the zona pellucida may lead to significantly reduced, or even complete, infertility in mares.
• The study also revealed that the presence of these antibodies does not necessarily correlate with mares’ oestrous cycles, and their absence at times suggests that multiple sampling may be required to eliminate false negatives.