Mucin coat is deposited on the embryos during passage through the oviduct in rabbit. When in vitro cultured blastocysts were transferred to the recipients, the lack of mucin coat might account in part for failure of pregnancy after transfer. The present study were carried out to investigate whether deposition of mucin coat were induced when in vitro cultured blastocysts were transferred to recipients. At 19 ～20 hours post-coitus one-cell embryos were collected by flushing oviducts. These embryos cultured for 72 hours were reached to blastocyst stage. And these blastocysts were transferred to the oviduct of asynchronized (one day later than the donors) and synchronized recipient. To confirm deposition of the mucin coat, blastocysts transferred to the oviduct were recovered at 24 and 48 hours after the transfer. Fifty eight percent of blastocysts recovered from uterus of asynchronous recipient at 24 hours after transfer and 92.9% of blastocysts recovered from uterus of synchronous recipient were 0～10 ㎛ of mucin coat thickness. And 11.8% of blastocysts of asynchronized recipients and 7.1% of blastocysts from asynchronized recipients were in 11～20 ㎛ of mucin coat thickness. When blastocysts were recovered from uterus at 48 hours after transfer, 87.0% of blastocysts from asynchronized recipients and 5.9% of blastocyst from synchronized recipients were in 0～10 ㎛ of mucin coat thickness. And 76.5% of blastocysts of synchronized recipients and 4.4% of blastocysts from asynchronized recipients were in 11～20 ㎛ of mucin coat thickness. From these results it is speculated that the low implantation rate of in vitro cultured rabbit blastocysts transferred to oviduct of recipient was caused by high degeneration of the embryo after transfer and inappropriate deposition of mucin coat.

INTRODUCTION   MATERIALS AND METHODS    Superovulation and Synchronization    Embryo Culture and Transfer    Recovery and Examination of Embryos   RESULTS    Recovery Rate of Blastocyst Transferred    Degeneration Rate of Blastocysts Recovered    Thickness of Mucin Coat of Blastocyst Recovered after Transfer   DISCUSSION   REFERENCES

• Joung S. Y(Research Center for Transgenic Cloned Pigs, Division of Animal Science and Resources, College of Agriculture and Life Sciences, Chungnam National University)
• Yang J. H(Research Center for Transgenic Cloned Pigs, Division of Animal Science and Resources, College of Agriculture and Life Sciences, Chungnam National University)
• Im K. S.(Department of Animal Science and Technology, College of Agriculture and Life Sciences, Seoul National University)
• Lee S. H.(College of Visual Image & Health, Kongju National University)
• Park C. S.(Research Center for Transgenic Cloned Pigs, Division of Animal Science and Resources, College of Agriculture and Life Sciences, Chungnam National University)
• Jin D. I.(Research Center for Transgenic Cloned Pigs, Division of Animal Science and Resources, College of Agriculture and Life Sciences, Chungnam National University)