Production of chimeric cattle embryos by reaggregation of blastomeres obtained from day 4 bovine embryos

Abstract

The aim of this study was to investigate the possibility of producing chimeric bovine embryos by reaggregating blastomeres of disaggregated day 4 bovine embryos. Oocytes were obtained from a slaughterhouse. Selected oocytes were matured, fertilized and cultured in vitro. Fertilization day was taken as day 0. Blastomeres of day 4 embryos were disaggregated and then pooled together. Chimeric embryos were randomly constructed by reaggregating blastomeres in empty zonae pellucidae. Non-chimeric handled control embryos were produced by transferring blastomeres from each embryo into their own empty zonae pellucidae. A total of 79 day 4 cattle embryos were used for disaggregation of blastomeres, and 27 chimeric and 12 non-chimeric handled control embryos were obtained from them. The rates of blastocyst formation of chimeric and non-chimeric handled control embryos were 40.7% (11/27) and 50.0% (6/12), respectively, and the difference between them was not statistically important (P > 0.05). These results showed the possibility of producing chimeric cattle embryos by reaggregating blastomeres obtained from day 4 embryos.