Recent Advances in Fertility Preservation and Genome Resource Banking for Rare and Endangered Animal Species

Cryo-storage of biomaterials from wild animal species offers many advantages from helping to understand the fundamental biology of unstudied species to making progress in veterinary medicine and enhancing breeding. While promoted since 1980s, the systematic banking of biomaterials from wildlife only recently has been considered to be a core function of animal conservation programs. For the preservation and use of gametes and gonadal tissues, protocols are species-specific, which requires considerable research efforts before developing and implementing biobanking and fertility preservation in any given species. So far, slow freezing of semen is the most common approach, but it is still not applied to many animal species. Storing frozen oocytes from wildlife is under development and has not been successful yet. However, testicular and ovarian tissues are increasingly considered as promising options to preserve germplasms from rare and endangered species. While methods to derive germplasms or produce embryos form somatic or stem cells are actively studied in wildlife, they have not contributed to any significant conservation efforts yet. In addition to cryo-storage, optimizing the reanimation and culture of germplasm post-freezing is an emerging research area in a growing number of species. Alternate preservation approaches at ambient temperatures also are explored to overcome the constraints and expenses related to liquid nitrogen storage. Lastly, proper integration of those technologies into conservation programs is critical while keeping in mind important ethical and welfare considerations.