[In vitro oocyte maturation in domestic ruminants].

In vitro maturation represents the first step towards the in vitro production of embryos in domestic species. This production is of great interest from both zootechnic and basic points of view. Beyond nuclear aspects of maturation (progression of meiosis to metaphase II) cytoplasmic aspects confer to oocytes their potential to be fertilized and to develop normally. The culture medium used for maturation could influence this competence. Furthermore, the origin of oocytes (physiologic and genetic status of the oocyte donor, characteristics of the follicle) could also be determinant. The improvement of in vitro maturation techniques will certainly require a better understanding of these different aspects. Additionally, the maintenance of the oocytes in meiotic block during a pre-maturation in vitro culture will allow them to complete the storage of molecules necessary for fertilization and development.