Developmental competence of domestic cat oocytes from ovaries stored at various durations at 4 degrees C temperature

Temporal storage of ovaries can provide opportunity to rescue oocytes from ovaries of endangered felids. The objective of the study was to examine the effect of different storage periods (2, 24 and 48h) of ovaries at 4 degrees C for maturation of cat oocytes in vitro. Ovaries were collected from 25 domestic cats at various stages of the estrous cycle by routine ovariohysterectomy following anesthesia at different local veterinary clinics, and maintained in physiological saline at 4 degrees C for 2, 24 or 48h until oocytes recovery. Selected COCs were maturated at 38 degrees C for 48h in four-well petri dishes, which included 500microL modified synthetic oviduct fluid (mSOF) medium under mineral oil in a humidified 5% CO(2), 5% O(2), and 90% N(2) atmosphere incubator. After the in vitro maturation period, there were no differences between the rate of oocytes matured at MII stages in 2 and 24h storage groups (50.7% and 48.2% respectively, p>0.05). However, the same result for the 48h group was significantly lower than the 2 and 24h groups (28.0%, p<0.001). Our results suggest that while 2 or 24h storage of ovaries at 4 degrees C does not affect the meiotic competence of oocytes in vitro, 48h storage of ovaries decrease the results dramatically.