Investigation of The Effects of in Straw Devitrification of In Vitro Produced Bovine Embryos Frozen by Vitrification on Embryo Viability

The aim of this study was to investigate embryo viability rates after devitrification in straw to use of these embryos for direct transfer technique in frozen bovine embryos by vitrification method. In the study, oocytes were provided from ovaries of slaughtered cows and a total of 84 embryos with good quality were produced in vitro. Embryos were frozen by vitrification method at 7th day of their culture and, devitrification process of thawed embryos were carried out in straws. For this purpose, thawed straws containing vitrification and devitrification solutions were mixed up by shaking. Control group of vitrified embryos were taken out of the straws for devitrification. In experimental groups, straws were devitrified at room temperature for three different time periods (G1 = 5, G2= 15 and G3 = 20 min.) After devitrification, embryos of all groups were cultured into TCM-199 medium and survivability controls of embryos were performed at 24 and 48 hours. There was no statistically significant difference among control and other groups regarding rates of embryo with intact ooplasm. Significant differences were obtained between the groups in point of embryo viability rates at 24 and 48 hours of culture environment, and viability rate of embryos were lower in experimental groups than those of controls (p<0.05). In conclusion, the air gap spacing between vitrification and devitrification solutions seemed to disable devitrification process, and hence further studies will be needed to assign the location of embrios, vitrification and devitrification solutions in straws for better devitrification process.