Development of the SCNT Embryo from Butyrolactone I Prematured Bovine Oocytes

The somatic cell nuclear transfer (SCNT) technique has been applied successfully in a range of mammalian species giving rise to offspring, however, the efficiency of development to term has remained low. Oocyte meiotic arrest is an important option to make the SCNT more flexible and increase the number of cloned embryos produced. This paper showed that the use of butyrolactone I to arrest the meiotic division for 24 h prior to in vitro maturation (IVM) provided bovine oocytes capability of supporting development of blastocysts as efficiently as non arrested oocytes. In the SCNT group, cleavage rates were not affected by prematuration when adding butyrolactone I during IVM (57.9% vs. 62.4%; control vs. 10 μmol · L−1 butyrolactone I), developmental rates to blastocyst were unaffected (22.0% vs. 20.3%; control vs. 10 μmol · L−1 butyrolactone I, p>0.05) by the addition of butyrolactone I during IVM in cloned embryos. Moreover, the total cell numbers of blastocyst were not affected by butyrolactone I (total nucleus numbers, 132±16.5 vs. 128±19.4, p>0.05). In conclusion, the SCNT embryos from butyrolactone I- prematured bovine oocytes had the same developmental potential as the non treated one. The present study provided a method for laboratories of in vitro embryos production, mainly those working on the SCNT, where prematuration could be used to increase the flexibility of the procedure.