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    Comparison of two different media for in vitro production of dog embryos
    (Veteriner Fakultesi Dergisi, 2010) Evecen M.; Cirit U.; Demir K.; Karaman E.; Bakirer G.; Hamzao?lu A.I.; Birler S.
    Embryo production via in vitro fertilization and nuclear transfer has been accomplished in the dog, and the transfer of the cloned embryos has recently resulted in the birth of puppies. However, the efficiency of these technologies is still very limited. Until now, only two morulas and single blactocyst have been achieved in vitro. Therefore, the aim of the present study was to examine the effects of two different media (mSOF and TCM 199) on in vitro maturation (IVM), in vitro fertilization (IVF) and in vitro culture (IVC) of immature dog oocytes. The study was performed in two steps. At the first step, the effects of two different media, on IVM of dog oocytes were investigated. At the end of the IVM period, the nuclear maturation rates were evaluated by aceto-orcein staining method. At the second step, after the IVM period the oocytes inseminated with fresh spermatozoa for 24 h and left for IVC for 7 d. At the end of the IVC period, embryonic development was assessed by microscopic observation at 24 h intervals and then fixed and stained by the same method. Consequently, maturation rates of oocytes in mSOF medium were significantly higher than those of the TCM 199 (P<0.001). After 7 d of the IVC period, only one oocyte was cleaved in the TCM 199, while eight oocytes cleaved and one of them developed to morula stage in mSOF medium group (P=0.037).
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    Öğe
    Effect of exposure duration to the vitrification medium on the post thaw development of in vitro derived bovine embryos
    (2012) Özdaş O.B.; Cirit U.; Demir K.; Bacinoğlu S.; Baran A.; Pabuccuoğlu S.; Irez T.
    Transfer of frozen embryos enables the establishment of elite herds, control of diseases and storage of genetic materials for longer periods. However, although intercontinental transfer of frozen embryos is possible, post-thaw degenerations are encountered and pregnancy rates are not at the expected level. Embryos especially degenerate during freezing and thawing procedures. These degenerations are thought to be due to the exposure time and toxic effects of used cryoprotectants. In this study slaughtered cattle ovaries were used. Oocytes were collected from ovaries using the aspiration method and matured in their own group in 700 microliter TCM-199 for 22-24 h at a gas atmosphere of 5% CO 2, 5% O2, and 90% N2 at 38.8 °C. Matured oocytes were fertilized for 18-24 h in IVF-TALP medium. After fertilization cleavage was 67.05% (865/1290) at 48th h. Embryos were cultured up to early blastocyst-blastocyst stage (34.91%; 302/865) in SOF medium supplemented with 10 % FCS for 7 days at a gas atmosphere of 5% CO 2, 5% O 2, and 90% N 2 at 38.8 °C. 302 embryos at the early blastocyst stage were frozen after an exposure to vitrification solution for various time periods (15, 30, 60, and 90 sec). Four groups have been established for this purpose (Groups 1, 2, 3, 4). Each group has included 67, 64, 63 and 60 embryos, respectively. All embryos were first kept in PBS solution containing 10% Glycerol + 10% FCS (Vs1) for 5 minutes and then in PBS containing 10% Glycerol+10% FCS+20% Ethylene Glycol (Vs2) solution for 5 minutes. Later, embryos were taken to straw containing vitrification solution (Vs3), 25% Glycerol + 10% FCS + 25% Ethylene Glycol + 0.1 M sucrose, and exposed for various time periods (15, 30, 60 and 90 sec), then frozen by dipping into liquid nitrogen. After thawing (37 °C) embryos were washed several times in washing medium supplemented with 0.5 M sucrose and SOF medium, then embryos of each group were incubated again for another 48 hours. Chi-square test was used in this study. Post thaw development to expanded blastocyst stage was highest in Group 1 with 52.2% (35/67) followed by Group 2 with 45.3% (29/64), Group 3 with 22.2% (14/63) and Group 4 with 5% (3/60). No statistical significance was observed between Groups 1 and 2. The statistical difference between Group 1 and 3 and between Group 1 and 4 were at P<0.01 and P<0.001 levels, respectively.
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    Öğe
    The effect of modified ovsynch protocol on synchronization and fertility rate in tahirova ewes
    (2012) Alkan S.; Kaşikçi G.; Cirit U.; Özdaş O.B.; Can Gündüz M.; Uçmak M.; Turna Yilmaz O.
    Tahirova ewes are known as a breed with high milk production. Nowadays, easy, economic and effective methods are developed for synchronization of cattle. The aim of this study was to adapt the Ovsynch protocol for cattle to the ewes. For this purpose 150 Tahirova ewes and 6 rams were used. The ewes in breeding season were randomly divided into three groups. On day 0 GnRh and day 6 PGF2?+PMSG administered to each of the ewes. In addition to this hCG was injected to the ewes of Group 2 and 3 on the 8th day and also estradiol propionat (EP) was administered to the ewes of Group 3 on the day 7.5. Matings have taken place in 68% of Group 1 on the first day and in 32% on the second day. These results were 80% on the first day, 8% on the 2nd day and 12% on the 3rd day in Group 2; 72% on the first day, 11% on the 2nd day and 6% on the 3rd day in Group 3. In Group 1 there were 9 twins (18.7%) out of 48 births. In Group 2 total 49 births, of which 11 twins (22.4%) and in Group 3, 5 (10.4%) of 48 births were twins. By the present study, the reproductive and breeding characteristics of Tahirova, a highly productive and adopted sheep have been determined and recorded. The ovsynch protocol which had been developed for dairy cattle have been modified for sheep and named as EWESYNCH.