What is new in the cryopreservation of embryos?

Embryo cryopreservation represents a pivotal tool for the long-term storage and exchange of valuable genetic resources of livestock and endangered species. The innumerable applications of embryo cryopreservation in human medicine, animal production, as well as in other embryo biotechnologies for research purposes are calling for standardized protocols that can be used in these different fields. This review will provide the reader with a brief outline to “the classics” of embryo cryopreservation procedures in farm animals and with a deeper insight into “the new trends”. Moreover, the cryopreservation effects on the embryo will be revised; from the easily visible cellular damage to the damage at the transcriptomic, proteomic and lipidomic level, and fresh attention will be given to the epigenetic effects of this technology. Finally, we will go through personal considerations to take into account when embryo cryopreservation is used: how to select the best embryos for cryopreservation, the eternal question for how long can we store the cryopreserved embryos, the fact that size and fat matter when it comes to embryo cryopreservation and ultimately, our suggestion about designing cryopreservation protocols “à la carte” attending the needs of each type of embryo.