• Korean Journal of Animal Reproduction
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• v.24 no.3
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• pp.225-230
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• 2000

This study was designed to investigate effect of cryoprotectant kinds and cell stages on the viability of bovine embryos cryopreserved by vitrification. The oocytes were collected from ovarian follicles of Korean native cows. The follicular oocytes were cultured in TCM-199 medium containing hormone and 10%(v/v) FCS for 24~48hrs in a incubator with 5% $CO_2$, in air at 38.5$^{\circ}C$ and then matured oocytes were again cultured for 7~10 hrs with spermatozoa capacitated by preincubation. The vitrification solutions of EFS and EDS were consisted of 40%(v/v) ethylene glycol, 18%(v/v) Ficoll and 0.3M sucrose, and 20%(v/v) ethylene glycol, 16.5%(v/v) DMSO and 0.5M sucrose in TCM-199 medium supplemented with 10% FCS, respectively. The embryos were exposed to EFS or EDS at $25^{\circ}C$ and loaded into OPP straw for 30 sec. The plug end of each straws was heat-sealed and straws was slowly immersed into liquid nitrogen(L$N_2$). The results obtained were summarized as follows : 1 . The rates of cleavage and hatching of embryos frozen with vitrification, rapid and slow freezing methods were 67.5%, 27.5% and 42.5%, 20.0% and 52.5%, 25.0%, respectively And rates of cleavage and hatching of embryos frozen with vitrification method were significantly(p<0.05) higher than those in other methods, and the rates were lower than those in control group(82.5% and 37.5%). 2. The rates of cleavage and hatching of embryos were significantly(p<0.05) different between EFS(47.5% and 22.5%) and EPS(52.5% and 27.5%), and the rates were lower than those in control group(82.5% and 37.5%). 3. After vitrification freezing of bovine embryos at zygote, 2 cell, 8 cell, morulae and blastocyst stage, the rate of cleavage and hatching were 25.0% and 15.0%, 32.5% and 20.0%, 37.5% and 20.0%, 52.5%, 27.5%, 47.5% and 25.0%, respectively. And developmental rates to the expended blastocyst stage of embryos frozen at zygote stage was significantly(p<0.05) lower rather than those in 2, 8-cell and morulae stage.