Simplification of the method to prepare equine embryos before cryopreservation by vitrification

Abstract

Embryo cryopreservation combined with embryo transfer is a very useful reproductive biotechnology for the equine sector. Until now, the conventional technique used required the purchase of expensive equipment and lengthy technical training. In addition to a microscope and two micromanipulators, two kinds of micropipettes connected to screw syringes were necessary, one to hold the embryo under air suction and one under oil. These constraints made the technique difficult to use in the field by the collection and transfer centres of the equine industry. At INRAE Nouzilly, we have developed a technique based on the freehand introduction of an aspiration micropipette through the capsule of the embryo, under a stereomicroscope. This is followed by the removal of the blastocoelic liquid via the micropipette. The operation is performed under oil, with the micropipette held by the operator and connected to a screw syringe. This technique was the subject of a declaration of invention and innovation. We have shown that this technique can be easily performed by a laboratory technician without experience in embryo micromanipulation and that it can achieve results in terms of in vitro embryo survival as good as the conventional technique. These two advantages make it possible to envisage the easy and effective use of this technique by equine embryo collection/transfer centres and the equine industry in general.