Effect of homologous follicular fluid from medium-sized and large follicles on in vitro maturation of equine cumulus-oocyte complexes.

This research investigates different methods of in vitro maturation (IVM) of equine oocytes. The researchers found that using follicular fluid from the horses’ own cycle promotes better maturation compared to synthetic mediums especially over longer incubation periods.

Research Background and Aims

• The aim of the research was to discover the best In Vitro Maturation (IVM) system for equine cumulus-oocyte complexes (COCs).
• The standard IVM process for equine oocytes involves the use of synthetic media. However, this study sought to determine if follicular fluid (FF) from the horses’ own reproductive cycle could offer improved results.

Research Methodology

• The research involved the collection of follicular fluid (FF) from medium-sized and large follicles in cyclic mares. The process was carried out using transvaginal ultrasound-guided follicle aspiration.
• Compact and non-compact COCs were obtained from a slaughterhouse and incubated in groups using different FF types and incubation periods.
• The groups included: FF from medium follicles for 24 hours, FF from large follicles for 24 hours, synthetic control medium for 24 hours, FF from medium follicles for 24 hours followed by FF from large follicles for an additional 24 hours, FF from large follicles for 48 hours, and synthetic control medium for 48 hours.

Research Findings

• The tendency was observed for more COCs incubated in FF from large follicles for 24 hours to reach metaphase II compared with those treated in control medium for 24 hours.
• More COCs were found to have degenerated after incubation in control medium for 48 hours as compared to all other groups.
• For non-compact COCs, incubation in FF from medium follicles for 24 hours resulted in more COCs reaching metaphase II compared with the control medium for 48 hours.
• The results suggest that homologous FF from cyclic mares could prove more suitable for the IVM of equine COCs than synthetic media, particularly for extended incubation periods.

Research Implication

• The findings from this research could help in developing more efficient and successful methods for equine oocyte maturation, which is vital in the field of animal breeding and conservation.