Development of a New Improvement and Multiplication System in Domestic Animals Using a Embryonic Manipulation Technique I. Effect of Maturation Time on the Extrusion Rate of First Polar Body and the Enucleation Rate of Bovine Follicular Oocytes

세포조작 기술을 이용한 새로운 축산개량증식 체계 개발 I. 소 난포란의 성숙시기가 제 1극체 출현율과 핵제거율에 미치는 영향

In this study, methods on fabrication of microtool and setting of micromanipulator were examined and relationship between first polar body extrusion rate and maturation time of follicular oocyte, enulceation rae and repetition of trial, and enucleation rate and maturation period were investigated. The results are as follows: 1. Suitable outside diameter of micropipette tube was 1mm. Holding pipette with less than diameter of oocyte was fitred for manipulation, and zona dissection needle was easily operated when its sharp-point had diameter of about 8 ${\mu}{\textrm}{m}$ and length of 300${\mu}{\textrm}{m}$. The injection pipette with 20~35${\mu}{\textrm}{m}$ outside diameter was adequate for injection of blastomere into perivitelline space. 2. Separation of blastomere was effective when zona pellucida had cut with zonadissection needle and the embryo was pipetted gently with the pipette that had narrower diameter than that of embryo until separation of blastomeres had completed. 3. The extrusion rate of first polar body was 78% during 20~24% hours incubation for maturation. 4. According to repetitions of micromanipulation, the enucleation rate was increased to 85% and the time required for enucleation of a oocyte was shortened to 3 min. 5. The extrusion rate of first polar body and enucleation rate were 82 and 76% respectively, in the group of the oocytes cultured for 22 hours. However in the group cultured for 24 hours, the extrusion rate of first polar body and enucleation rate were 53 and 100% respectively.