title: Electrical activation enhances pre-implantation embryo development following sperm injection into in vitro matured pig oocytes.
abstract: The objective of this study was to evaluate the effect of electrical stimulation (EST) on pronuclear formation, chromosomal constitution, and developmental capability among in vitro matured pig oocytes following intracytoplasmic sperm injection (ICSI). After ICSI, the oocytes were randomly distributed and cultured into 3 groups: the EST activated ICSI group, non-activation ICSI group, and in vitro fertilization (IVF) group. The proportion of oocytes in which 2 pronuclei were formed in ICSI groups was significantly higher in the former groups than in the IVF group (96.2 and 93.5 vs. 64.5%, respectively, P<0.05). The cleavage rate was significantly higher in EST activated ICSI group (78.6%) than in the IVF and non-activated ICSI groups (51.8 and 46.0%, respectively, P<0.05), as was the proportion of oocytes that developed to the blastocyst stage at day 7 (18.9 vs. 11.6 and 9.1%, respectively, P<0.05). Diploid blastocysts were observed in 52.4, 63.0, and 65.2% of oocytes in the IVF, activated, and non-activated ICSI groups, respectively. Eight out of 23 gilts (34.8%) were confirmed to be pregnant in activated ICSI groups, but none of these pregnancies were carried to term. These results show that oocyte activation after ICSI is effective in elevating the cleavage rate and blastocyst development, while ensuring normal chromosome composition. Further research is needed to determine the pregnancy maintenance requirements for ICSI-embryos in pigs.
authors: Division of Animal Science, National Institute of Animal Science, Rural Development Administration, Suwon, Gyeonggi 441-706, Republic of Korea.
authors: Jae-Gyu
authors: JG
authors: Yoo
authors: Chang-Gi
authors: CG
authors: Hur
authors: Mi-Rung
authors: MR
authors: Park
authors: Jong-Yi
authors: JY
authors: Park
authors: Kyu-Chan
authors: KC
authors: Hwang
authors: Jae-Hwan
authors: JH
authors: Kim
authors: Jin-Hoi
authors: JH
authors: Kim
authors: Seong-Keun
authors: SK
authors: Cho
mesh_terms: D000818:Animals; D004558:Electric Stimulation; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D008297:Male; D009865:Oocytes / Q000502:physiology*; D011247:Pregnancy; D011897:Random Allocation; D020554:Sperm Injections, Intracytoplasmic / Q000662:veterinary*; D013552:Swine / Q000502:physiology*