Parthenogenetic Activation of Porcine Oocytes by Calcium Ionophore A23187

Abstract. This study was designated to clarify the influence of activation of porcine matured oocytes by calcium ionophore on in vitro development of the parthenotes. The follicular oocytes were matured, activated and cultured in North Carolina State University-23 (NCSU-23) medium supplemented with 10% porcine follicular fluid (pFF). The in vitro-matured oocytes were exposed to calcium ionophore at concentrations of 12.5, 25 or 50 μM for 3, 5, 7 or 9 min. The activation rate of the oocytes increased as concentration of ionophore decreased, being at 27–33 and 68–77 % for the oocytes treated with 50 and 12.5 μM ionophore, respectively. Almost all activated oocytes were haploid. The highest cleavage rate (76%) and developmental rate to morula (41%) were observed in the oocytes treated with 12.5 μM ionophore for 5 min. However, development to blastocyst was observed only in the oocytes treated with 25 μM ionophore for 3 and 5 min (3 and 4% of treated oocytes, respectively). We concluded that the activation treatment of the porcine oocytes with 12.5 μM ionophore for 5 min provided the highest develop-mental rate to morula, but this treatment is not sufficient to overcome a developmental block at the morula stage.