Effect of the in vitro maturation medium on equine oocytes: comparison of follicular fluid and oestrous mare serum.

The research article discusses a study on the impact of supplementing the medium for in vitro maturation of equine oocytes with either oestrous mare serum (EMS) or horse follicular fluid (HFF). The study found that the presence of either EMS or HFF in the medium resulted in more matured oocytes, with the mediums containing glutamine leading to the highest proportions of degenerated oocytes.

Objective and Methodology of the Study

• The main objective of the study was to investigate the effect on equine oocytes when the maturation medium is supplemented with two different substances: oestrous mare serum (EMS) or horse follicular fluid (HFF).
• Ovaries from mares aged 16-21 months were obtained, transported to the lab, and the oocytes were extracted. The selection of oocytes for in vitro maturation (IVM) was based on the number of the surrounding cumulus cells and cytoplasmic attributes.

In Vitro Maturation Process

• The selected oocytes underwent a washing process in one of two mediums: TCM199 medium plus HEPES (TCM-199H) or the same medium but supplemented with glutamine (TCM-199G). After washing, they were subjected to in vitro maturation (IVM)
• Six study groups were established for the IVM process to study potential interactions between HEPES and glutamine on different supplements.
• For two of these groups, the medium was supplemented with 10% EMS, and for another two groups, 10% HFF was added. The IVM process was carried out at a controlled atmosphere and temperature.

Findings of the Study

• The study observed that mediums that contain either EMS or HFF with TCM-199H resulted in the highest proportions of matured oocytes (37.7% and 36.8%, respectively), suggesting that both EMS and HFF were beneficial for oocyte maturation.
• However, it’s important to note that the statistical difference between EMS and HFF was not significant, so one cannot definitively say one is better than the other. Both, however, significantly outperformed the other treatments.
• Mediums containing glutamine gave rise to a higher proportion of degenerated oocytes, suggesting it might not be beneficial to the oocyte maturation process.