Abstract
The present experiment was designed to investigate the in vitro development of bovine embryos and the maturaton and follicular oocytes after a short-term storage at 4°C. A total of 80 embryos were recovered 6 or 7 days after estrus in superovulated or naturally ovulated Holstein cows.
A total of 183 oocytes surrounded with cumulus cell mass were collected by puncturing thse follicles with a diameter of 5 mm. The embryos and oocytes were stored in sterile siliconized test tubes containing 1.5 ml PBS (modified phosphate buffered saline with 20% fetal calf serum) for 0-96 h and 0-48 h respectively. The test tubes were placed in a 300 ml beaker containing 200 ml of water at room temperature and then refrigerated at 4°C.
After 36 h storage, the embryos were cultured in Ham's F10 for 48-72 h. The percentage of theseembryos that developed into expanded blastocysts was 42.0% as compared with 84.0% for those embryos cultured immediately after collecting from the donors (P< 0.05). In vitro maturation rate of the oocytes cultured in Ham's F12 for 24-27 h after 6 h storage was markedly decreased (34.2%) as compared with the non-stored oocytes (62.1%).
These results indicate that bovine embryos and follicular oocytes can be refrigerated for up to 24 h and 2 h, respectively, without decreasing their viability.
