Developmental Competence of In Vitro Matured Porcine Oocytes after Electrical Activation.

Abstract

Developmental competence of in vitro matured porcine oocytes obtained by TCM199- and NCSU 23-based IVM systems after electrical activation were compared. When the nuclear phase of granulosa-cumulus-oocyte complexes (GCOCs) used in the TCM199-based IVM system and cumulus-oocyte complexes (COCs)used in the NCSU 23-based IVM system were observed, most of GCOCs were fully grown dictyate arrest oocytes (GV I, 68.6%), on the other hand, only 33.8% of COCs were at GV I stage. There were no differences in the rates of maturation (93.2%, 82/88 vs 91.3%, 63/69), normal cleavage (70.7%, 58/82 vs 65.1%, 41/63) and development to blastocysts (37.8%, 31/82 vs 34.9%, 22/63) between the in vitro matured oocytes obtained by the two IVM systems. However, the parthenogenetic blastocysts derived from the NCSU23-based IVM system had higher cell numbers than the blastocysts derived from the TCM199-based IVM system (35.6 ± 4.5 vs 22.6 ± 2.0; P<0.01). Transfer of parthenogenetic oocytes derived from the NCSU23-based IVM system resulted in a high developmental rate to somite stage fetuses (26.9%, 45/167). These data demonstrate that the activated porcine oocytes derived from the two IVM systems had equal ability of in vitro development, though there was a difference in the cell number of the parthenogenetic blastocysts. It was also shown that in vitro matured oocytes obtained by the NCSU23-based IVM system had excellent ability of parthenogenetic development to fetuses, indicating that they are usable in porcine developmental engineering.