Abstract:

【Objective】 In order to obtain high efficient method to produce porcine haploid parthenogenetic embyos, different physical and chemical methods were applied to activate MII porcine oocytes. 【Method】 In experiment 1, electrical activation, a combination of electrical activation and cytochalasin B (CB),and ethanol activation at different concentrations and durations were used to activate porcine oocytes. In experiment 2, electrical activation followed by MG-132 or Thimerosal/DTT treatments were investigated for their effects on porcine oocytes activation. 【Result】 The results of experiment 1 indicated that the development rates of blastocysts in CB group(27.34%)were significantly higher than that of electrical activation alone (16.92%) (P＜0.05), and both of them were significantly higher than that of all ethanol groups (P＜0.05). In all ethanol groups, 9% ethanol treatment for 11 min got the highest blastocyst rate (10.20%) . The results of experiment 2 showed that the rate of blastocysts formation in MG-132 group (24.69%) was not significantly different with that of CB group (27.50%), but they were significantly higher than that of Thimerosal/DTT (14.10%) and electrical activation (17.5%) groups (P＜0.05). The ploidy analysis of blastocysts derived from different groups indicated that the percentages of haploid blastocysts in electrical activation, 9% ethanol and Thimerosal /DTT group were 41.7%, 40%, and 35.3% respectively, they were significantly higher than that of CB (0) and MG-132 (6.7%) groups (P＜0.05)【Conclusion】 Considering both blastocysts formation rate (out of oocytes) and haploid rate (out of total blastocysts), the final haploid blastocyst percentages (out of oocytes) in electrical activation, 9% ethanol, Thimerosal/DTT and MG-132 groups were 7.3% (17.5%×41.7%), 4.1% (10.2%×40%), 5.0% (14.1%×35.3%), and 1.7% (24.69%×6.7%), respectively. The electrical activation might be the best activation way to obtain haploid embryos.

Key words: porcine oocytes, in vitro maturation, parthenogenetic activation, rate of haploid