Abstract：The relationship between [Ca2+] in activation medium and electrical pulse strength on parthenogenetic activation of porcine oocytes was examined , and the application of sorbitol was also discussed. It was showed that:(1) The cleavage rates (73.75% and 74.70%) and blastocyst rates（37.50% and 36.83%) obtained under 0.05 mmol/L [Ca2+] and 1.6 kV/cm pulse strength, and 0.1 mmol/L Ca2+ and 1.2 kV/cm, respectively, were significantly higher than that under other conditions (P < 0.05). However, under excessive level of [Ca2+], increase electrical pulse strength led to high degradation and low development rate. (2) Using sorbitol as electro-activation medium, the highest cleavage (77.23%) and blastocyst rates (34.15%) could be obtained under 1.6 kV/cm DC. (3) Be differ from mannitol electro-activation medium, development of parthenogenetic embryos of sorbitol group was not improved with the addition of alternating current (AC) pulse. (4) Using equally mixed sorbitol and mannitol as electro-activation medium, the cleavage rates were 72.33% and 70.03% under 1.2 and 1.6 kV/cm electrical pulse, and blastocysts rates were 31.03% and 29.60%, respectively. The development of mixture group was a little lower than mannitol group (77.07% and 36.03%), and higher than that of sorbitol group (69.63% and 26.93%), but no significantly difference (P > 0.05). These results demonstrated that parthenogenetic activation of porcine oocytes needs a threshold level of [Ca2+]. Under this level, embryo developmental ability can be improved by increase the electrical pulse strength. Sorbitol can replace mannitol as fundamental component in electro-activation of porcine oocytes. Mixture of sorbitol and mannitol also get a satisfied activation results.
