title: Development of large and small blastomeres from 2-cell embryos produced in vitro in pigs.
abstract: In the present study, we examined the development to blastocysts of large and small blastomeres from unevenly cleaved 2-cell embryos (uneven 2-cell embryos) in pigs. Proportion of blastocysts derived from large blastomeres (52.8 ± 6.4%) was significantly higher (P<0.05) compared with small ones (32.1 ± 4.6%). However, there were no differences in total cell number, inner cell mass (ICM) cell number and ICM/total cells ratio between them. Of 53 sister blastomere pairs in the same embryos examined there were 12 pairs (22.6%) in which both blastomeres developed to blastocysts, 16 pairs (30.2%) in which only large blastomeres developed to blastocysts, and five pairs (9.4%) in which only small blastomeres developed to blastocysts. Relative total amount of active mitochondria in small blastomeres were lower (P<0.05) than that of large blastomeres and blastomeres from evenly cleaved 2-cell embryos. However, there was no difference in relative density of active mitochondria in these three types of blastomeres. In conclusion, blastocysts derived from small and large blastomeres in uneven 2-cell embryos had comparable quality in terms of cell number, ICM number, ICM/total cell ratio and distribution of active mitochondria. The results suggest that these blastomeres may contribute multiple offspring production in pigs.
authors: Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi, Vietnam; Animal Breeding and Reproduction Division, NARO Institute of Livestock and Grassland Science, Tsukuba, Japan; Graduate School of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Japan.
authors: Thanh Quang
authors: TQ
authors: Dang-Nguyen
authors: Nguyen
authors: N
authors: Viet-Linh
authors: Tamas
authors: T
authors: Somfai
authors: Seiki
authors: S
authors: Haraguchi
authors: Bui
authors: B
authors: Xuan Nguyen
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology; D001757:Blastomeres / Q000166:cytology*; D002970:Cleavage Stage, Ovum; D005260:Female; D066298:In Vitro Techniques; D008928:Mitochondria / Q000648:ultrastructure; D013552:Swine / Q000196:embryology*
keywords: embryo centrifugation; mitochondria; two-cell embryo; uneven cleavage