A Comparative Study on the Parthenogenetic Development of Pig Oocytes Cultured in North Carolina State University-23 and Porcine Zygote Medium-3

초록

The objective of this study was to examine the effect of in vitro culture media on embryonic development of in vitro-matured (IVM) oocytes after parthenogenetic activation (PA) in pigs. Immature pig oocytes were matured in TCM-199 supplemented with porcine follicular fluid, cysteine, pyruvate, EGF, insulin, and hormones for the first 22h and then further cultured in hormone-free medium for an additional 22～26 h. IVM oocytes were activated by electric pulses and cultured in porcine zygote medium-3 (PZM-3) and North Carolina State University-23 supplemented with essential and non-essential amino acids (NCSU-23aa). These media were further modified by supplementing 2.77mM myo-inositol, 0.34 mM trisodium citrate, and 10 μM β-mercaptoethanol (designated as mPZM-3 and mNCSU-23aa, respectively). Culture of PA embryos in mPZM-3 significantly increased development to the blastocyst stage than culture in NCSU-23aa (36.2% vs. 24.8%, p<0.05). Modified PZM-3 showed a significantly higher blastocyst formation than NCSU-23aa in both groups of embryos that were activated at 44 h and 48 h of IVM (51.0% vs. 35.5%and 49.0% vs. 34.2% in oocytes activated at 44 h and 48 h of IVM, respectively). Irrespective of the follicle diameter where oocytes were collected, embryonic development to the blastocyst stage was increased (p<0.05) by the culture in mPZM-3 compared to culture in NCSU-23aa (25.9% vs. 34.2% and 32.9% vs. 44.8% in embryos derived from small and medium size follicles, respectively). Our results demonstrated that culture media had significant effect on preimplantation development PA embryos and that mPZM-3 was superior to mNCSU-23 in supporting development to the blastocyst stage in pigs. This beneficial effect of mPZM-3 on embryonic development was not impaired by other factors such as time of oocyte activation and origin of immature oocytes (small and medium size follicles).

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