Abstract
In vitro fertilized 8-16-cell stage embryos, co-cultured with cumulus cells for 117 hours, were divided into two groups. Embryos in one group (control group) were further co-cultured with cumulus cells or cultured in TCM199 supplemented with 10 μM β-mercaptoethanol (β-ME). Embryos in the other group were used as donor nuclei for nuclear transfer. The nuclear transferred eggs were co-cultured with cumulus cells to the 8-16-cell stage. They were divided into two; half of them were further co-cultured with cumulus cells and the others were cultured in TCM199 supplemented with β-ME to the bla-stocyst stage as control group. The proportions of embryos which developed to blastocysts in β-ME supplemented medium in both groups were not significantly different from those obtained in the co-culture system. However, the proportions of nuclear transferred eggs which developed to blastocysts in both groups were significantly different from those obtained in in vitro fertilized eggs.
