Our results suggested that IUGR piglets showed apparent ER stress in the colon, as indicated by the increases in the mRNA abundance of GRP78, GRP94, CHOP, ATF4, and sXBP-1 and the protein levels of GRP78, CHOP, and c-Casp12 (P < 0.05; Fig. 3a and b). This evidence concerns the gene ATF4 and fetal growth restriction.