Effects of holding time and media on meiotic and developmental competence of horse oocytes

摘要

A major barrier to progress in assisted reproduction in the horse is lack of adequate numbers of developmentally competent equine oocytes for study. Since there are relatively few horse abattoirs, horse ovaries may be transported long distances to the laboratory before processing. Previous studies have found no effect of ovary storage up to 15 h after slaughter on the meiotic competence of horse oocytes [1,2]; however, in these reports the shortest duration of ovary storage was 1.5-4 h. Laboratories which recover oocytes soon after ovary removal from the mare have reported relatively high rates of oocyte maturation [3], suggesting that even a few hours storage of horse ovaries may influence the meiotic competence of oocytes. No information is available on the effect of ovary storage on developmental competence (potential for embryo development) of horse oocytes. This study was conducted to evaluate the effect of short-term ovary storage on the rate of in vitro maturation of horse oocytes and on their developmental competence, as reflected by rates of embryonic cleavage and number of nuclei after fertilization by intracytoplasmic sperm injection (ICSI).