Exogenous infusion of short-chain fatty acids can improve intestinal functions independently of the gut microbiota.

The present experiment was conducted to investigate the effects of exogenously infused with short-chain fatty acids (SCFAs) on the growth development and intestinal functions in a germ-free (GF) pig model. Twelve hysterectomy-derived newborn piglets were reared in six sterile isolators. All piglets were hand-fed Co60-γ-irradiated sterile milk powder for 21 days, then were switched to sterile feed for another 21 days. During the second 21-days period, GF piglets (n = 6) were orally infused with 25 mL/kg sterile saline per day, SCFA piglets (n = 6) were orally infused with 25 mL/kg SCFAs mixture (acetic, propionic, and butyric acids, 45, 15, and 11 mM, respectively) per day. We observed the concentrations of SCFAs in serum and intestine, and the mRNA abundance of GPR43 in ileum was increased (P < 0.05) in the SCFA group. Meanwhile, oral infusion of SCFAs enhanced (P < 0.05) the contents of GLP-2 in jejunum and serum, tended to increase the villi height in ileum (P < 0.10). Besides, the activities of lipase, trypsin, sucrase, lactase, and Na +-K +-ATPase (P < 0.05) and Ca 2+-Mg 2+-ATPase (P < 0.10) were stimulated and the mRNA expressions of SLC7A1 and REG-ΙΙΙ γ in jejunum (P < 0.05) were upregulated in the SCFA group. Additionally, SCFAs infusion downregulated the mRNA abundances of IL-1β and IL-6 in jejunum, ileum, or colon (P < 0.05), and increased the counts of WBC, NEUT, and LY in the blood (P < 0.05). Collectively, exogenous infusion of SCFAs might improve intestinal health through promoting intestinal development and absorption function, and enhancing intestinal immune function, and was occur independently of the gut microbiota.