PARTHENOGENETİC ACTIVATION OF SHEEP OOCYTES

In order to establish somatic- and embryonic-cell nuclear transfer procedures in sheep in our laboratory, two activation protocols for parthenogenetic activation of sheep oocytes were tested. Oocytes obtained from ovaries of slaughtered ewes were matured for 24 h in medium 199 supplemented with pyruvate, hormones (FSH and LH) and 10% FCS. After maturation, all oocytes were exposed to single electrical stimulation of 1.25 kV/cm for 80 |isec, then placed into ionomycine and cytochalasin B for 5 min and 30 min respectively, and then divided into 2 groups randomly. While oocytes in Group I were incubated in 6- dimethylaminopurine (6-DMAP) for 2 h, oocytes in Group II were kept in cycloheximide (CHX) for 3 h before transferring into culture medium. Cleavage and blastocyst rates in groups I and II were 82.7% and 81.3%, and 2.3% and 0% respectively (P>0.05). These are our preliminary results for the parthenogenetic development of sheep oocytes in Turkey and represent promising results in the direction to achieve sheep cloning.