Cryopreservation of in vitro produced bovine embryos

Yancho Todorov, Tanya Todorova

Abstract: In order to compare the survival rate of bovine embryos frozen by different protocols, oocytes derived from ovaries in slaughterhouses were used for IVM, IVF and IVC. Expanded blastocysts were cryopreserved by slow freezing at 0.3 ºC/min, and vitrification was done using ethylene glycol + sucrose (ES). After thawing, the embryos were co-cultivated on a monolayer of granulosa cells and evaluated after 24 hours for re-expansion. At 24, 48, 72 and 96 hours the stages of development and hatching were determined. The degree of in vitro survival (hatching of 96 hours) of frozen by slow freezing method embryos at a cooling rate of 0.3 ºC/min (76.44%) was similar to that obtained for the control group (88.8% without cryopreservation). Vitrification using ES showed survival rates of 18.9%. In conclusion, in our hands, the slow freezing with 0.3 °C/min was the best method for cryopreservation of in vitro derived bovine embryos.

Keywords: cattle; cryopreservation; IVC; IVF; vitrification

Date published: 2018-10-04