Sixteen IUGR and 8 NBW (normal body weight) neonatal piglets were chosen, weaned at 7th day and fed basic milk diets (NBW and IUGR group) or the basic diets supplemented with 0.1% tributyrin (IT group, IUGR piglets fed with tributyrin) until day 21 (n = 8). The body weights of the piglets on days 0, 7, 10, 14, 17, and 20 were measured. The digestive enzyme activity, intestinal morphology, immunoglobulin levels and gene expression of IgG, FcRn and GPR41 in the small intestines were analyzed.

The body weights of the piglets in the IUGR and IT group were similar, and both were lower than the NBW group on days 10 and 14. However, after day 17, the IT group exhibited improved (P < 0.05) body weights compared to that of the IUGR group. The piglets were sacrificed on day 21. Compared with the NBW piglets, IUGR impaired the development of immune organs and small intestines, impaired the intestinal villus morphology, decreased (P < 0.05) most of the tested intestinal digestive enzyme activities, decreased (P < 0.05) the ileal sIgA and IgG levels, and down-regulated (P < 0.05) the intestinal IgG and GPR41 expression. Piglets in the IT group exhibited a better-developed (P < 0.05) spleen and small intestines, improved intestinal villus morphology, increased (P < 0.05) intestinal villus surface areas, enhanced (P < 0.05) digestive enzyme activities, and up-regulated (P < 0.05) expression of IgG and GPR41 mRNA compared to those of the IUGR group.

TB supplementation improves the growth and the intestinal digestive and barrier functions in IUGR piglets during the suckling period.