Effects of ultraviolet irradiation on in vitro development of parthenogeneticand somatic nuclear transferred embryos in bovine

Effects of ultraviolet(UV) irradiation on the cleavage and in vitro development of parthenogenic and somatic cloned embryos in bovine were investigated. The results showedthat the cleavage and blastocyst development rates of parthenogenic embryos derived from oocytes irradiated with UV for 20s and 40s were significantly lower than those of oocytes irradiated with UV for 0s and 10s(P0.01). It indicated that irradiating oocytes with UV for longer than 20s decreased the developmental potential of parthenogenic embryos significantly. In cloning research, although the cleavage rate of reconstructed embryos derived from the enucleated oocytes suffered from UV irradiation for 20s is significantly lower than that of enucleated oocytes suffered from UV irradiation for 0s and 10s (P0.01), the blastocyst development rate had no significant difference among them. The cleavage rate and blastocyst development rate of reconstructed embryos derived from enucleated oocytes suffered from UV irradiation for40s were lower than other groups significantly. The results indicated that irradiating enucleated oocytes with UV for longer than 20s decreased the cleavage and in vitro developmental potential of reconstructed embryos. In cloning research, the UV irradiation should be shorter than 20s when the Hoechst dye and UV irradiation were used in the enucleation, while 10s UV irradiation on enucleated oocytes haven't any harmful effect on the development of reconstructed embryos.