Birth of somatic cell nuclear transfer (SCNT)-cloned miniature piglet following co-transfer of parthenogenetic embryos
2009
Sugimura, S.(Tohoku Univ., Sendai (Japan)) | Yamanaka, K. | Wakai, T. | Kawahara, M. | Tanaka, H. | Kobayashi, J. | Kobayashi, E. | Sato, E.
In miniature pigs, establishment and maintenance of pregnancy to term is required to implant at least 4 or 5 viable embryos. However, most of the somatic cell nuclear transfer (SCNT)-derived miniature pig embryos are lost in the peri- or post-implantation stages. Thus, it is important to develop strategies for improving the chances of implantation and maintenance of pregnancy in order to produce viable SCNT cloned miniature piglets. In present study, we investigated the effect of co-transfer of parthenogenetic (PA) embryos with SCNT-derived embryos on the establishment and maintenance of pregnancy and production of SCNT-cloned miniature piglets. PA embryos exhibited higher in vitro developmental competence to blastocyst stage (PA: 31.2% vs. SCNT: 6.6%) and total number of cells at blastocyst stage (PA: 35.1+-3.3 vs. SCNT: 22.9+-1.0) as compared to the SCNT embryos. Further, SCNT embryos were transferred alone or co-transferred with PA embryos into recipient miniature gilts. On ultrasonography at day 50 after embryo transfer, no pregnancy was detected in the only-SCNT group, while 3 pregnancies were detected in the co-transfer group. One of the 3 successful pregnancies completed term and delivered a single, healthy SCNT-cloned miniature piglet. Furthermore, the weight increase in the SCNT-cloned miniature piglet was similar to that of the piglet derived from in vivo fertilized embryos. These data indicated that co-transfer PA embryos could support the establishment and maintenance of pregnancy and help achieve full-term development of SCNT embryos, which have a low developmental competence.
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