title: Littermate influence on infant growth in mice: comparison of SJL/J and ICR as cotransferred carrier embryos.
abstract: In mice, a minimum number of healthy embryos is required to trigger and maintain pregnancy. Therefore, when recovering mouse embryos from a limited litter, one useful technique is to transfer carrier ICR embryos along with the embryos of interest, a technique referred to as cotransfer. In this study, we examined suitable mouse strains for cotransfer with C57BL/6J (B6) embryos in regards to the maintenance of pregnancy, number of pups born, intrauterine growth, and postnatal growth. Because the coat color of B6 is black, we compared two white coat-colored strains, SJL/J and ICR. Cotransfer of SJL/J and ICR embryos had similar effects on maintenance of pregnancy, number of pups born, and intrauterine growth. However, the postnatal growth of B6 mouse pups cotransferred and grown with SJL/J pups was better than for B6 mouse pups cotransferred and grown with ICR pups, suggesting competition among littermates. These results demonstrate that cotransfer of SJL/J embryos will be useful not only as carrier embryos with B6-background embryos but also as a model system to examine littermate competition.
authors.affiliation: Bioresource Center, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, Gunma 371-8511, Japan.
authors.forename: Ryosuke
authors.initials: R
authors.lastname: Kaneko
authors.forename: Toshie
authors.initials: T
authors.lastname: Kakinuma
authors.forename: Sachiko
authors.initials: S
authors.lastname: Sato
authors.forename: Atsushi
authors.initials: A
authors.lastname: Jinno-Oue
authors.forename: Hidekazu
authors.initials: H
authors.lastname: Hata
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D004624:Embryo Transfer; D005260:Female; D008098:Litter Size / Q000502:physiology*; D008297:Male; D008810:Mice, Inbred C57BL / Q000196:embryology* / Q000254:growth & development*; D008813:Mice, Inbred ICR / Q000196:embryology* / Q000254:growth & development*; D011247:Pregnancy