Abstract   

    This study was performed 1) to compare different ratios of foetal calf serum (FCS) for in vitro maturation (IVM) of sheep oocytes and 2) to investigate different culture media and supplements for ovine embryo production in vitro.  Primary oocytes collected from ovaries of slaughtered Kivircik ewes were divided into 2 groups randomly and incubated in vitro for 26 hours at 39°C in a humidified atmosphere of 5% CO₂ in air, TCM 199 medium supplemented with 10mg/ml follicle stimulating hormone, 10mg/ml luteinizing hormone, 1 mg/ml estradiol 17β and 10% FCS (low) or 20% FCS (high) was used as maturation medium. After in vitro maturation and fertilization, presumptive zygotes were again divided into 2 groups randomly, and co-cultured for 6 days with sheep oviductal epithelial cells. In the first culture group (TCM), TCM 199 medium supplemented with 55 sheep estrous serum (SES), and in the second group synthetic oviduct fluid (SOF) medium supplemented with 20% SES were used. The cleavage and morula rates among groups (low +TCM, high+TCM, low+SOF, High+SOF) were 38.8^ab, (38/98), 33.3^b, (28/84), 52.0^a (53/102) and 53.0 ^a (44/83); and 22.4^ab (22/98), 16.7^b (14/84), 31.4^a (32/102) and 34.9%^a (29/83), respectively. Differences among groups with different letters (a, b) were important statistically (p<0.05). The results of this study showed that in vitro culture (IVC) of sheep embryos derived in vitro could be better in SOF medium than TCM 199.    

Key words: Sheep, IVM, Serum supplementation, TCM 199.