Impact of retrieval method and transport conditions of domestic cat oocytes on In vitro embryo production.

As assisted reproductive technologies in wild felids gain importance, establishing reliable protocols for sample transport becomes a priority. The recent development of ovum pick-up (OPU) techniques in felids has highlighted the lack of standardized protocols for oocyte transport, particularly under field conditions. This study evaluated the effects of oocyte recovery method (slicing vs ex vivo OPU) and oocyte transport conditions on subsequent in vitro developmental competence and embryo production. In an initial experiment, ovaries were stored at 4 °C for 24 h to examine the effect of whole-ovary transport. No significant differences were observed in blastocyst production rate compared with controls processed immediately (9.8% vs 16.1%). In two additional experiments, oocytes recovered either by slicing (SLI) or OPU were processed immediately (0 h) or after 18 h in embryo holding medium, and nuclear maturation (experiment 2), cleavage, and embryo development (experiment 3) were evaluated. No significant interaction was detected between storage time and processing method (P > 0.05), suggesting that the influence of storage time on the assessed parameter was independent of the processing method. Additionally, neither storage time nor processing method showed significant main effects (P > 0.05). The maturation stage was also unaffected. Blastocyst production was more sensitive to storage duration than earlier stages, with rates of 22.6% (SLI 0 h) vs 11.9% (SLI 18 h) and 27.0% (OPU 0 h) vs 13.0% (OPU 18 h). Despite lower developmental outcomes compared with other species, acceptable blastocyst yields and hatched embryos were obtained across treatments. These findings support the short-term maintenance of feline oocytes at room temperature in holding medium and highlight its potential value for felid in vitro embryo production programs when immediate laboratory processing is not feasible.