체외 배양액의 조성과 혈청의 첨가가 한우 체외 수정란의 발달과 임신율에 미치는 효과

Abstract

The present study investigated the efficient methods to produce in vitro Hanwoo embryos, and to improve the pregnancy rate. The developmental rate, total cell number and ICM ratio of in vitro embryos were compared amongst different culture media. Comparisons were also made on the status of recipients, pregnancy rate along with day of transfer after the estrus. Development of embryos into blastocyst stage in IVMD101 supplemented with 5% fetal bovine serum (FBS) group was significantly higher (34.2%) than that of TCM-199 supplemented with 5% FBS (26.8%) and IVMD101 without FBS (25.9%) (p<0.05). The development rate to blastocyst stage was significantly faster in IVMD101(5% FBS) than that of other groups (0.2～2.3%) (p<0.05). The average number of inner cell mass and trophectoderm were similar among treatment groups, which were 36.0～44.7 and 83.3～106.7. However, total cell number in IVMD101(5% FBS and 0% FBS) was significantly higher than that of TCM199(5% FBS). There were no differences in the pregnancy rate among treatment groups (32.0%, 33.9% and 28.6%, respectively). However, the pregnancy rate of Day 6 embryos cultured in IVMD101(5% FBS) was significantly (p<0.01) higher than IVMD101 without FBS and TCM-199 + 5% FBS (38.0% vs. 17.2% and 32.4%, respectively). No significant difference was observed for the pregnancy rate between heifer and cow transferred with Day 6 embryos cultured in IVMD 101(5% FBS) (42.7% and 39.3%, respectively). However, there was a significant difference of pregnancy rate (p<0.05) in heifer between one and two embryos transferred (31.4% and 41.9%). There was no difference of pregnancy rate among transfer days after estrus between heifer and cow, but the pregnancy rate of transfer to heifer with day 6 after estrus was significantly higher (p<0.05) than that of day 7 and 8 (22.2% vs. 49.0% and 38.7% respectively). Based on the above findings, there is a possibility to produce in vitro produced embryos cultured in IVMD101(5% FBS) showed higher blastocyst rate and the increased cell number. In terms of the pregnancy rate of in vitro produced embryos, the highest pregnancy rate was observed when two embryos were cultured in IVMD101(5% FBS) and transferred.