Blastocoele formation and cell allocation to the inner cell mass and trophectoderm in haploid and diploid pig parthenotes developing in vitro

The objective of this study was to determine developmental pattern and cell allocation to the inner cell mass and trophectoderm in haploid and diploid embryos following parthenogenetic activation. In vitro matured porcine oocytes were activated by ethanol treatment and cultured in the presence or absence of cytochalasin B for 5 h. The oocytes were then cultured in the NCSU23 for 9 days. The combined treatment with cytochalasin B following ethanol treatment did not increase (p>0.1) the incidence of activation. The incidence of development to the blastocyst stage was higher (p<0.05) in the combined treatments of ethanol and cytochalasin B as compared with ethanol treatment alone. The percentage of oocytes with two female pronuclei was higher (p<0.01) in oocytes treated with cytochalasin B than that in ethanol treatment alone. Treatment with both ethanol and cytochalasin B increased (p<0.01) the incidence of diploid chromosome spread over just the ethanol treatment alone. The average numbers of total cells and inner cell mass were significantly reduced (p<0.05) in the ethanol treatment alone as compared with the combined cytochalasin B and ethanol treatment. These results suggested that the ploidy may affect blastocoele formation and cell allocation to inner cell mass and trophectoderm in the pig.