LARGE-SCALE ISOLATION OF EQUINE ZONAE-PELLUCIDAE

A simple and rapid method is described for the large-scale isolation o f cumulus cell-free, zona pellucida-intact equine oocytes. Aspiration of palpable antral follicles present on frozen-thawed equine ovaries w as accomplished using a constant vacuum source. The resultant follicul ar fluid, oocytes, and particulate matter were then filtered through a series of nylon screens of alternating mesh openings in combination w ith sodium citrate-containing buffer to a final volume of approximatel y 20 ml. This fluid was transferred to scored Petri dishes and a stere omicroscope was used to locate the oocytes for further processing or s torage. The methodology described is inexpensive, time-efficient, and the recovery rate is similar to or better than other methods previousl y described for equine oocyte recovery. Collected oocytes are adequate for biochemical evaluation of the equine zona pellucida (EZP) as well as sperm-egg binding assays.