Characteristics of the gut microbiota colonization, inflammatory profile, and plasma metabolome in intrauterine growth restricted piglets during the first 12 hours after birth.

Intrauterine growth restriction (IUGR) predisposes newborns to inflammatory and metabolic disturbance. Disequilibrium of gut microbiota in early life has been implicated in the incidence of inflammation and metabolic diseases in adulthood. This study aimed to investigate the difference in gut microbiota colonization, cytokines and plasma metabolome between IUGR and normal birth weight (NBW) piglets in early life. At birth, reduced (P < 0.05) body, jejunum, and ileum weights, as well as decreased (P < 0.05) small intestinal villi and increased (P < 0.05) ileal crypt depth were observed in IUGR piglets compared with their NBW counterparts. Imbalanced inflammatory and plasma metabolome profile was observed in IUGR piglets. Furthermore, altered metabolites were mainly involved in fatty acid metabolism and inflammatory response. At 12 h after birth and after suckling colostrum, reduced (P < 0.05) postnatal growth and the small intestinal maturation retardation (P < 0.05) continued in IUGR piglets in comparison with those in NBW littermates. Besides, the gut microbiota structure was significantly altered by IUGR. Importantly, the disruption of the inflammatory profile and metabolic status mainly involved the pro-inflammatory cytokines (IL-1β and IFN-γ) and amino acid metabolism. Moreover, spearman correlation analysis showed that the increased abundance of Escherichia-Shigella and decreased abundance of Clostridium_sensu_stricto_1 in IUGR piglets was closely associated with the alterations of slaughter weight, intestinal morphology, inflammatory cytokines, and plasma metabolites. Collectively, IUGR significantly impairs small intestine structure, modifies gut microbiota colonization, and disturbs inflammatory and metabolic profiles during the first 12 h after birth. The unbalanced gut microbiota mediated by IUGR contributes to the development of inflammation and metabolic diseases.