Effects of Dietary l‑Arginine and N‑Carbamylglutamate Supplementation on Intestinal Integrity, Immune Function, and Oxidative Status in Intrauterine-Growth-Retarded Suckling Lambs

This study investigated the effects of dietary l-arginine (Arg) and N-carbamylglutamate (NCG) supplementation on intestinal integrity, immune function, and oxidative status in intrauterine-growth-retarded (IUGR) suckling lambs. A total of 48 newborn Hu lambs of normal birth weight (CON) and IUGR were allocated randomly into four groups of 12 animals each: CON, IUGR, IUGR + 1% Arg, or IUGR + 0.1% NCG. All lambs were raised for a period of 21 days from 7 to 28 days after birth. The Arg or NCG group exhibited improved (p < 0.05) final body weights compared to that of the IUGR group. In comparison to the IUGR lambs, the apoptotic percentage was lower (p < 0.05) in the ileum of IUGR lambs supplemented with Arg and NCG. In addition, in comparison to IUGR, the concentrations of protein carbonyl and malondialdehyde were lower (p < 0.05) and the reduced glutathione (GSH) concentration and ratio of GSH/oxidized glutathione were greater (p < 0.05) in the jejunum, duodenum, and ileum of IUGR + 1% Arg or 0.1% NCG lambs. In comparison to the IUGR group, the mRNA abundance of myeloid differentiation factor 88, toll-like receptor 9, toll-like receptor 4, interleukin 6, and fuclear factor-κB was lower (p < 0.05) and the mRNA abundance of superoxide dismutase 1, B-cell lymphoma/leukaemia 2, zonula occludens-1 (ZO-1), and occludin was greater in the ileum of the IUGR lambs supplemented with Arg or NCG. Furthermore, the protein abundance of ZO-1 and claudin-1 in the ileum was greater (p < 0.05) in the IUGR + 1% Arg or 0.1% NCG lambs. The results show that Arg or NCG supplementation improves the growth, intestinal integrity, immune function, and oxidative status in IUGR Hu suckling lambs.