Effect of age and media on the quality and developmental abilities of equine oocytes from slaughterhouse ovaries

Abstract

In vitro assisted reproductive techniques in horses have experienced considerable improvement in the last years. Although the results of in vitro fertilization are still very poor in horses, intracytoplasmatic sperm injection (ICSI) has been proved to be an efficient and successful technique to produce in vitro embryos and is become very popular in the equine industry. Before ICSI can take place, the oocytes have to mature to metaphase II in vitro. Different maturation media have been developed in the horse and their correct composition is paramount for a correct oocyte development. Moreover, maternal age has been shown to have a significant impact on oocyte quality and development abilities in other domestic species. The purpose of this study was to evaluate the effect of the media and of maternal age on the quality of equine oocytes evaluated on the base of morphology and fluorescent DNA staining. One hundred forty two oo-cytes were used. With the collection, the ovaries were divided in two groups; young mares with the age up to 14 years and old mares with the age more than 15 years. However, there was no significant difference developmental or morphology between the two age groups. Also the two media used had no significant effect on either the phase of replication or the morphology of the oocytes. Further research is needed to determine the direct effects of maternal age on the quality and developmental abilities of oocytes.