New methods for gamete rescue from gonads of nondomestic felids

Methods for rescuing oocytes and spermatozoa post mortem are described, which were adapted from domestic cat as a model. Ovaries were mechanically processed for large-scale recovery of oocytes. Numbers of intact cumulus-oocyte complexes (COCs) per animal and of preantral follicles per ovary were 18 +/- 2 and 2892 +/- 665 in domestic cats, respectively. Similar results were obtained from 13 individuals of 6 nondomestic felids: 16 +/- 2 COCs and 1867 +/- 1144 follicles. Preantral follicles were cultured for at least 7 days. Intact COCs were maturated for 24 h and fertilized in vitro with homologous or heterologous (from domestic cat) spermatozoa. Spermatozoa were collected from caudae epididymides (n = 11; five nondomestic species) and cryopreserved (n = 8) using a programmed freezer. The reproductive competence of oocytes collected post mortem was demonstrated by development to embryos (> or = 8 cells) in vitro. Spermatogenic efficiency of males was assessed by flow cytometric analysis of mitotic and meiotic testicular cells as well as by estimation of testosterone concentration in testes. The results demonstrate the possibility of retrospective assessment of male and female reproductive capacity. In conclusion, the described methods could be a useful part of gamete rescue programmes for endangered felids.