TNF and fetal growth restriction: More remarkably, recent experiments identified an increased abundance of Escherichia-Shigella and a decreased abundance of Clostridium_sensu_stricto_1 in IUGR piglets, which was closely associated with the alterations of cytokines (tumor necrosis factor-α, interleukin-6, interleukin-1β and interferon-γ,) and plasma metabolites in the first 12 h of life (unpublished data), suggesting early-life interactions between intestinal microbiota and the intestinal immune function in IUGR piglets.