Dietary resistant starch protects against post-antibiotic intestinal damage by restoring microbial homeostasis and preserving intestinal barrier function in meat duck

Abstract

Resistant starch (RS) is recognized as a nutritional strategy that supports gut and overall host health by modulating gut microbiota. To directly assess the effects of RS on gut microbiota and its role in improving intestinal barrier function in meat ducks, this study first established an antibiotic-induced microbial dysbiosis model, which was characterized by reduced gut microbial diversity, intestinal dysfunction, and an inflammatory outburst following antibiotic exposure. Whereafter, in addition to the control group, ducks treated with antibiotics for 7 consecutive days were further allocated to two groups and fed the basal diet and RS diet that derived from 12 % raw potato starch until 21 d. The results demonstrated that dietary RS supplementation reversed the antibiotic-induced reduction in microbial diversity and restored the Firmicutes-to-Bacteroidetes ratio. Additionally, RS inclusion enriched beneficial bacterial genera, including Coprobacter, Odoribacter, and Faecalibacterium (LDA score > 3). Post-antibiotic intervention led to a reduction in villus density and muscular thickness, accompanied by a significant downregulation (P < 0.05) of zonula occludens-1 and mucin-2 expression, along with increased serum pro-inflammatory cytokine levels (P < 0.05). Notably, dietary RS supplementation significantly enhanced (P < 0.05) the expression of glucagon-like peptide receptor and the anti-apoptotic factor Bcl-2, while suppressing caspase transcription. This resulted in increased villus height and muscular thickness in the ileum (P < 0.05). Furthermore, RS intervention remarkably reduced (P < 0.05) pro-inflammatory cytokine levels, particularly interleukin-1β and tumor necrosis factor-α, in both the ileum and serum. These effects were likely linked to alterations in cecal microbiota, including increased abundances of Barnesiella, Ruminiclostridium 9, Megamonas, Faecalitalea, Adlercreutzia, Coprobacter and Collinsella. In conclusion, dietary RS supplementation mitigated antibiotic-induced cecal microbial dysbiosis and restored intestinal structure by promoting enterocyte proliferation and reducing apoptosis. Consequently, RS supplementation helped alleviate systemic inflammation in meat ducks following antibiotic treatment.

Keywords: Antibiotic; Gut microbiota; Inflammation; Meat ducks; Resistant starch.

Fig. 1

Morphometric measurements of villus height (black bar), crypt depth (green bar), and muscular thickness (blue bars) on an ileum from a meat duck (hematoxylin and eosin staining, 100 ×).

Fig. 2

Schematic presentation of the experimental design (A) and gut microbial composition in cecal digesta are altered in antibiotic (AB)-treated duck at 14 d (B-G). Effect of AB on the principal co-ordinates analysis (PCoA) analysis (B), Chao1 richness (C) and Shannon diversity (D) indexes, and composition profiles of gut microbiota at phyla level (E), the ratio of the relative abundance of Firmicutes to Bacteroidetes (F), and the linear discriminant analysis (LDA) showing the bacterial taxa that were significantly different in abundance (G) of 14-d-old ducks. Data represent means with standard deviation represented by vertical bars (n = 6). *Letter on bars means a significant difference at P < 0.05.

Fig. 3

Effect of antibiotics (AB) on body weight (A), the gene expression of intestinal barrier-related (B) and pro-inflammatory cytokines in ileum (C), and the concentration of serum IFN-γ (E) and IL-1β in serum (D) of 14-d-old ducks. Data represent means with standard deviation represented by vertical bars (n = 6). *Letter on bars means a significant difference at P < 0.05.

Fig. 4

Effect of dietary resistant starch (RS) supplementation on body weight (A), survival proportions (B) and intestinal development of ileum (C-I): weight (C), length (D), H&E staining (40 ×; E), morphological indicators (F), and the gene expression of intestinal development-related genes (G), cell apoptosis (H) and intestinal barrier-related genes (I) in antibiotics (AB)-treated duck at 21 d. Data represent means with standard deviation represented by vertical bars (n = 8). *Letter on bars means a significant difference at P < 0.05. VH: villus height; CD: crypt depth; V/C ratio: villus height/ crypt depth ratio; MT: muscular thickness.

Fig. 5

Gut microbiota to dietary resistant starch (RS) supplementation in antibiotics (AB)-treated duck at 21 d: principal co-ordinates analysis (PCoA) analysis (A), Chao1 richness (B) and Shannon diversity (C) indexes, composition profiles of gut microbiota at phyla level (D), the relative abundance of Firmicutes and Bacteroidetes, and the ratio of the Firmicutes to Bacteroidetes (F/B ratio) (E), the linear discriminant analysis (LDA) showing the bacterial taxa that were significantly different in abundance (F). Data represent means with standard deviation represented by vertical bars (n = 8). *Letter on bars means a significant difference at P < 0.05.

Fig. 6

Inflammatory response to dietary resistant starch (RS) supplementation in antibiotics (AB)-treated duck at 21 d: the gene expression of inflammatory cytokines (A) and TLR4/MyD88/NFκB signaling (B) in ileum, pro-inflammatory cytokines levels in serum (C), and the mantel test network heat map analysis between microbial genera and serum inflammatory cytokines (D). Data represent means with standard deviation represented by vertical bars (n = 8). *Letter on bars means a significant difference at P < 0.05.