Impact of Equine and Bovine Oocyte Maturation in Follicular Fluid From Young and Old Mares on Embryo Production in Vitro.

This research studied the effect of horse (equine) and cow (bovine) oocyte maturation in the follicular fluid (FF) from young and old horses on in vitro (test tube) production of embryos. The results indicated that the follicular fluid from older mares did not have a negative impact on early development of horse or cow embryos.

Experiment and Hypothesis

• The researchers hypothesized that the process of oocytes maturing in follicular fluid from old horses as compared to young ones might have a negative effect on oocyte maturation and their subsequent developmental potential.
• They conducted two experiments to test this – one using horse oocytes, the other using cow oocytes. Both were matured in follicular fluid from young or old horses and then fertilized.

Types of Follicular Fluid

• Follicular fluid used in these experiments was of two types: Noninduced follicular fluid from noninduced follicles, and Induced follicular fluid collected after administering ovulation-inducing drugs to the mares.
• The noninduced follicular fluid was collected from follicles measuring 33 ± 3 mm, while the induced FF was collected around 24 hours after administering the ovulation-inducing drug, when a follicle of the same size was observed.

Experiment Results

• In the first experiment using horse oocytes, the results tended to show that more embryos (blastocysts) were produced from oocytes matured in the follicular fluid of older mares as compared to the fluid from younger mares.
• In the second experiment with cow oocytes, the oocytes matured in the follicular fluid from younger mares showed higher cleavage rates (a significant step in cell division) when the results of IFF and NFF groups were combined.
• Contrary to their initial hypothesis, the researchers found no conclusive evidence to suggest that follicular fluid from older mares has a negative impact on the oocytes and their early development.