Dietary corn resistant starch regulates intestinal morphology and barrier functions by activating the Notch signaling pathway of broilers.

Objective: The objective of this study was to investigate the effects of dietary corn resistant starch (RS) on the intestinal morphology and barrier functions of broilers. Methods: A total of 320 one-day-old broilers were randomly allocated to normal corn-soybean (NC) diet group, corn starch (CS) diet group, 4%, 8% and 12% resistant starch (RS) diet groups. Each group had eight replicates with eight broilers per replicate. After 21 days feeding, one bird with a body weight (BW) close to the average BW of their replicate was selected and slaughtered. The samples of duodenum, jejunum, ileum, caecum digesta and blood were collected. Results: We found that birds fed RS diets showed lower feed intake, BW gain, jejunal and ileal villus height (VH), duodenal and ileal crypt depth (CD), duodenal VH/CD ratio, duodenal GCD as well as mucin1 mRNA expressions compared to the NC group, but showed higher feed/gain (F/G) ratio, concentrations of caecal acetic acid and butyric acid, percentage of jejunal proliferating cell nuclear antigen (PCNA)-positive cells and Notch1, Dll4 and Hes1 mRNA expressions. However, there were no differences on the plasma DAO activity and D-lactic acid concentration among all groups. Conclusion: These findings suggested that RS can suppress intestinal morphology and barrier functions by activating Notch pathway and inhibiting the development of goblet cells, resulting in decreased mucins and tight junction mRNA expression.