Turkish Journal of Veterinary & Animal Sciences




The objective of the present study was to transfer sheep embryos produced in vitro to recipient ewes. Ovaries were taken from slaughtered Kıvırcık ewes and transferred to the laboratory in phosphate buffered saline (PBS) at 30-35 ºC. The cumulus-oocyte complexes were obtained by slicing and washing 1-6 mm diameter follicles and matured for 24 h in medium 199 supplemented with sodium pyruvate, follicle stimulating hormone (FSH), luteinizing hormone (LH) and 10% fetal calf serum (FCS) at 38.5 ºC under 5% CO_2 in humidified atmosphere. Fresh semen was collected from three Kıvırcık rams, pooled and prepared for in vitro fertilization by the percoll-gradient method. Matured oocytes were transferred into synthetic oviduct fluid (SOF) based fertilization medium supplemented with 2% sheep oestrous serum (SES) and co-incubated with semen (0.8 x 106 spermatozoon/ml) for 20-21 h. After fertilization, presumptive zygotes were transferred into SOF medium and incubated for 8 days under an atmosphere of 5% CO_2, 5% O_2 and 90% N_2 at 38.5 ºC. Glucose (1.5 mM) was added to the culture medium on day 4. In culture, embryos were checked for cleavage and embryo development on days 4 and 8, respectively. A total of 534 oocytes were inseminated in vitro, 407 (76.2%) cleaved, and 119 (29.2%) and 69 (16.9%) reached the morula and blastocyst stages, respectively. Forty days after the transfer of 40 blastocysts into the uteri of 17 recipient ewes, pregnancy was detected in 10 ewes (58.8%) by ultrasonography and 7 ewes gave birth to 8 live lambs. The other 3 ewes, which had 7 fetuses, could not have live offspring. According to the transferred embryos, the implantation rate was 37.5% and the live lamb rate was 20.0%.


Sheep, in vitro production, embryo transfer

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