Cryosurvival of ex situ and in situ feline oocytes

Significant advances in feline oocytes cryopreservation have recently been achieved. The oocyte is considered more susceptible to cooling damage than embryos and spermatozoa, however recent results demonstrate that banking of cryopreserved female gametes is an attainable goal. In Felids, as well as in other mammals, oocyte cryopreservation would significantly contribute to the improvement of assisted reproductive technologies aimed to the preservation of biodiversity. Besides the advantages in animal conservation, the use of animal models, as domestic cat, provides the opportunity for further investigations of the principles of oocyte cryobiology which can help to improve current technologies applied to both humans and animals. A review of the literature regarding survival of feline oocytes cryopreserved as isolated cells (ex situ) or enclosed in ovarian follicles (in situ) is provided