Abstract：This study aimed to assess some factors effecting the formation of nuclear extrusion on demecolcine-induced bovine oocytes, including oocyes with or without the first polar body, different demecolcine treatment concentration and duration. The result demonstrated: treated with 0.5 μg/mL demecolcine, oocytes induced for 1 h (76.00%) gained higher rate of extrusion than those for 0.5 h (61.18%)、1.5 h (64.10%) and 2 h (63.46%). And in 1 h demecolcine-treatment, 0.4 μg/mL and 0.5 μg/mL demecolcine led to the higher rate of extrusion (75.24% and 77.31% respectively) compared to the 0.3 μg/mL (46.54%) and 0.6 μg/mL group (60.66%). In addition, there was no significant difference on the extrusion rate between oocytes with (83.24%) or without (77.54%) first polar body. To sum up, bovine oocytes induced with 0.4 μg/mL demecolcine for 1h can gain the higher rate of extrusion. And demecolcine can assist enucleation effectively in Nuclear Transfer.
