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

Abstract

Objective: This study was conducted 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 5 dietary treatments: one normal corn-soybean (NC) diet, one corn-soybean-based diet supplementation with 20% corn starch (CS), and 3 corn-soybean-based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS) (identified as 4% RS, 8% RS, and 12% RS, respectively). 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: Birds fed 4% RS, 8% RS and 12% RS diets showed lower feed intake, BW gain, jejunal villus height (VH), duodenal crypt depth (CD), jejunal VH/CD ratio, duodenal goblet cell density as well as mucin1 mRNA expressions compared to the NC group, but showed higher concentrations of cecal acetic acid and butyric acid, percentage of jejunal proliferating cell nuclear antigen-positive cells and delta like canonical Notch ligand 4 (Dll4), and hes family bHLH transcription factor 1 mRNA expressions. However, there were no differences on the plasma diamine oxidase activity and D-lactic acid concentration among all groups.

Conclusion: These findings suggested that RS could 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.

Keywords: Barrier Function; Broiler; Corn Resistant Starch; Intestinal Morphology.

Figure 1

The periodic acid–Schiff staining of goblet cells in duodenum, jejunum and ileum villus of 21-day-old broilers (Arrows point to goblet cells). NC, a basic normal corn–soybeandiet; CS, a corn–soybean–based diet supplementation with 20% corn starch (CS); 4% RS, 8% RS, and 12% RS, the corn–soybean–based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS), respectively. Image, magnification at ×200.

Figure 2

The PCNA immunohistochemical assessment of duodenum, jejunum and ileum villus of 21-day-old broilers (Arrows point to PCNA-positive cells).NC, a basic normal corn–soybeandiet; CS, a corn–soybean–based diet supplementation with 20% corn starch (CS); 4% RS, 8% RS, and 12% RS, the corn–soybean–based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS), respectively; PCNA, proliferating cell nuclear antigen. Image, magnification at ×400.

Figure 3

Effects of corn resistant starch on the relative mRNA expressions of mucin1, mucin2, claudin-1, occludin, ZO-1, and ZO-2 in jejunal mucosa of 21-day-old broilers. Results are represented as the mean value±standard error of the mean (n = 8). ^a,b Means in a row without a common superscript letter significantly differ (p<0.05). NC, a basic normal corn–soybean diet; CS, a corn–soybean–based diet supplementation with 20% corn starch (CS); 4% RS, 8% RS, and 12% RS, the corn–soybean–based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS), respectively; ZO-1, zonula occludens-1; ZO-2, zonula occludens-2.

Figure 4

Effects of corn resistant starch on the relative mRNA expressions of notch1, notch2, DLL1, DLL4, Hes1, and Atoh1 in jejunal mucosa of 21-day-old broilers. Results are represented as the mean value±standard error of the mean (n = 8). ^a–c Means in a row without a common superscript letter significantly differ (p<0.05). NC, a basic normal corn–soybean diet; CS, a corn–soybean–based diet supplementation with 20% corn starch (CS); 4% RS, 8% RS, and 12% RS, the corn–soybean–based diets supplementation with 4%, 8%, and 12% corn resistant starch (RS), respectively. DLL1, delta like canonical Notch ligand 1; DLL4, delta like canonical Notch ligand 4; Hes1, hes family bHLH transcription factor 1; Atoh1, atonal homolog 1.