Korte beschrijving

Assisted reproductive technologies (ART) are the solution to many fertility problems in humans and animals. The use of animals as models for the study of human ART has been fundamental to its development. The cow and the human share a few important reproductive characteristics, making this species an excellent model for human ART The general objective of the present thesis is to improve the current individual in vitro embryo production system in cattle. Today, the best results are obtained with the group culture system, in which 40-50% of the in vitro fertilized oocytes reach the blastocyst stage. Individual maturation, fertilization and embryo culture has the advantage that the final result of in vitro embryo production (blastocyst rate and quality) can be directly related to the original oocyte (ovarian origin, maturation conditions with or without addition of follicular fluid, cumulus oocyte morphology and cumulus expansion). We studied the effect of different concentrations of follicular fluid during oocyte maturation on cumulus expansion, embryo development and quality in an individual culture system. The follicular fluid provides the ideal microenvironment to support the growth and maturation of the oocyte. The effect of supplementing follicular fluid on the maturation medium in a completely individual culture system has not yet been studied. We hypothesized that supplementing in vitro maturation (IVM) medium with follicular fluid would improve embryo development and quality under individual and group culture conditions. We could indeed show that 5% of follicular fluid supplementation during IVM improved the cumulus expansion and the blastocyst development and quality in an individual culture system.