Effective Activation Method of in Vitro Maturation of Pig Ovum

2003-11-01

This study sought to establish maturation culture and activation methods for immature pig ovum, where in vitro maturation of ovum occurs at a high rate during the blastocyst stage of the embryo. In the activation method, butyrolactone -1(BL-1), which shows inhibitory effect, was used in addition to electric stimulation of kinase in the cell cycle.

Period in Solution Had No Significant Effect on Maturation Rates

Maturation rates of 79.6, 81.6, and 83.6% were obtained for immature pig ovum in the maturation culture solution, when cultivated for 36, 42, and 48 hours, respectively, but the difference was not significant.

BL-1 Processing and Electric Stimulation

The activation rate in the 36-hour culture was significantly lower (P<0.05) compared to those in other culture time. Also, the proportion of normal activation ovum was low in any of the culture time, as a result of carrying out the activation by combined use of BL-1 processing and single electric stimulation.

Division Rate of Blastocyte Culture

For the mature ovum cultivated for 48 hours, after the activation was carried out by the combined use of electric stimulation and BL-1 processing, generation culture was carried out using Whitten and mNCSU37 culture solution. The division rate and incidence of blastocyst stage embryo were then examined in the second and sixth culture. In addition, the blastocyst stage embryo was also examined for cell population.

Results of the study show that giving electric and activation stimulation after 48 hours of maturation culture using butyrolactone-1, as well as the use of mNCSU37 for the extracorporeal generation of immature pig ovum, are effective.

For further information, see Bing, Y.Z., Hirao, Y., Iga, K., Che, L.M., Takenouchi, N., Kuwayama, M., Fuchimoito, D., Rodriguez-Martinez, H., and Nagai, T. 2002. In Vitro Maturation and Glutathione Synthesis of Porcine Oocytes in the Presence or Absence of Cysteamine under Different Oxygen Tensions: Role of Cumulus Cells. Reproduction, Fertility and Development 14: 125-131.

Imai, K., Kobayashi, S., Kaneyama, K., Kojima, T., and Nagai, T. 2002. Effects of Butyrolactone-I on GVBD in Bovine Oocytes and Subsequent Maturation, Fertilization and Development In Vitro. Journal of Reproduction and Development 48:249-255.

Nguyen, V.T., Kure-bayashi, S., Harayama, H., Nagai, T., and Miyake, M. 2003. Stage-specific effects of the osmolarity of a culture medium on the development of parthenogenetic diploids in the pig. Theriogenology 59:719-734.

Download the PDF. of this document, 22,036 bytes (21.5 KB).