Microbiome-metabolomics analysis insight into the effects of dietary resistant starch on intestinal integrity.

Resistant starch (RS) has caught much attention for its potential to exert a beneficial impact on intestine and certain members of its resident microbiota. In this study, we examined how dietary RS promotes intestinal barrier in meat ducks by microbiome-metabolomics analysis. Ducklings were fed corn-soybean basal diet or RS diet. Dietary RS improved intestinal morphology and enhanced barrier function in ileum, evidenced by lower permeability and upregulated tight junction proteins and Mucin-2 gene expression. Microbiome analysis showed that RS administration elevated the proportion of Firmicutes and butyrate-producing bacteria, and increased butyrate contents in cecum. Furthermore, significant alterations in metabolic profiles were observed, with most of these were associated with the amino acid metabolism (especially tryptophan), lipid metabolism, and intestinal inflammation. Together, diet with RS improved gut integrity and caused corresponding alterations in gut metabolome and microbiome, yielding better insights of the mechanism by RS improved the gut system of ducks.

Dietary resistant starch alleviates Escherichia coli-induced bone loss in meat ducks by promoting short-chain fatty acid production and inhibiting Malt1/NF-κB inflammasome activation.

BACKGROUND: Escherichia coli (E. coli) infection in humans and animals usually comes with gut dysbiosis, which is potential culprit to skeletal health, it is still unclear to whether diet interfered gut microbiome changes can be a protective strategy to bone loss development. Here, the effects of resistant starch from raw potato starch (RPS), a type of prebiotic, on E. coli-induced bone loss and gut microbial composition in meat ducks were evaluated. RESULTS: The results showed that dietary 12% RPS treatment improved bone quality, depressed bone resorption, and attenuated the pro-inflammatory reaction in both ileum and bone marrow. Meanwhile, the 12% RPS diet also increased the abundance of Firmicutes in E. coli-treated birds, along with higher production of short-chain fatty acids (SCFAs) especially propionate and butyrate. Whereas addition of ß-acid, an inhibitor of bacterial SCFAs production, to the drinking water of ducks fed 12% RPS diet significantly decreased SCFAs level in cecum content and eliminated RPS-induced tibial mass improvement. Further, treatment with MI-2 to abrogate mucosa-associated lymphoid tissue lymphoma translocation protein 1 (Malt1) activity replicated the protective role of dietary 12% RPS in E. coli-induced bone loss including reduced the inhibition on nuclear factor κB (NF-κB) inflammasome activation, decreased bone resorption, and improved bone quality, which were correlated with comparable and higher regulatory T cells (Treg) frequency in MI-2 and 12% RPS group, respectively. CONCLUSIONS: These findings suggested that the diet with 12% RPS could alleviate E. coli-induced bone loss in meat ducks by changing the gut microbial composition and promoting concomitant SCFAs production, and consequently inhibiting Malt1/NF-κB inflammasome activation and Treg cells expansion.

Calcium supplementation in low nutrient density diet for meat ducks improves breast meat tenderness associated with myocyte apoptosis and proteolytic changes.

To define the relationship between dietary nutrient density, calcium (Ca), and meat quality in meat ducks. A total of 288 male Cherry Valley SM3 medium ducklings were fed a common standard starter diet until d 14. At 15 d of age, ducks were randomly divided into 2 treatment groups and fed either a conventional diet or a low nutrient density (LND) diet. Compared with the conventional diet, the energy was reduced in the LND diet by 8.6% and 16.8% in grower (15 to 35 d) and finisher (36 to 56 d) phases, respectively, while other essential nutrients were kept proportionate to energy. The LND diet decreased the shear force (P < 0.05) and increased the lightness values of the pectoralis muscle when compared to the conventional diet, suggesting that LND diet exerted a beneficial role in meat quality. Subsequently, the effects of grated Ca in the LND diet on meat quality of pectoralis muscle were evaluated. A total of 576 male ducklings were fed a common starter diet until d 14, followed by feeding 4 LND diets with 0.5%, 0.7%, 0.9%, and 1.1% Ca. The results show that LND diets with 0.7% or more Ca decreased the shear force of pectoralis major muscle in 42-d-old meat ducks (P < 0.05). To explore the mechanism underlying Ca and tenderness, data from birds fed either 0.5% or 1.1% Ca in the LND diet indicated that birds fed 1.1% Ca exhibited lower shear force, upregulated calpains 1 expression, and higher calpains activity compared to those fed the LND diet with 0.5% Ca (P < 0.05). Moreover, the 1.1% Ca LND diet induced a higher myocyte apoptosis (P = 0.06) and upregulated mRNA expression of caspase-3 (P = 0.07) in breast muscle. Our data suggest that LND diets with 0.9% or 1.1% Ca had a positive role in the tenderness of breast meat, particularly the enhancing effect of 1.1% Ca LND diet on tenderness seems to be associated with proteolytic changes of myofibrillar proteins and myocyte apoptosis in meat ducks.

Dietary resistant starch ameliorating lipopolysaccharide-induced inflammation in meat ducks associated with the alteration in gut microbiome and glucagon-like peptide 1 signaling.

BACKGROUND: Consumption of resistant starch (RS) has been associated with various intestinal and systemic health benefits, but knowledge of its effects on intestinal health and inflammatory response in stressed birds is limited. Here, we examined how dietary RS supplementation from 12% raw potato starch (RPS) modulated inflammatory severity induced by lipopolysaccharide (LPS) in meat ducks. RESULTS: LPS administration at 14, 16, and 18 d (chronic challenge) decreased body weight (BW) and glucagon-like peptide 1 receptor (GLP-1R) level with higher intestinal permeability and inflammation, evident by higher pro-inflammatory cytokine levels. Dietary 12% RPS supplementation enhanced Claudin-1 and GLP-1R expression, along with lower levels of inflammatory factors in both ileum and serum. Microbiome analysis showed that RS treatment shifted microbial structure reflected by enriched the proportion of Firmicutes, Bifidobacterium, Ruminococcus, etc. Dietary RS addition also significantly increased the concentrations of propionate and butyrate during chronic LPS challenge. Furthermore, response to acute challenge, the ducks received 2 mg/kg BW LPS at 14 d had higher concentrations of serum endotoxins and inflammatory cytokines, as well as upregulated transcription of toll like receptor 4 (TLR4) in ileum when compared to control birds. Analogous to GLP-1 agonist liraglutide, dietary RS addition decreased endotoxins and inflammation cytokines, whereas it upregulated the GLP-1 synthesis related genes expression. Meanwhile, dietary RS supplementation suppressed the acute LPS challenge-induced TLR4 transcription. CONCLUSIONS: These data suggest that dietary 12% RPS supplementation could attenuate the LPS-induced inflammation as well as intestinal injury of meat ducks, which might involve in the alteration in gut microbiota, SCFAs production and the signaling pathways of TLR4 and GLP-1/GLP-1R.

Dietary Resistant Starch From Potato Regulates Bone Mass by Modulating Gut Microbiota and Concomitant Short-Chain Fatty Acids Production in Meat Ducks.

Gut microbiota interfered with using prebiotics may improve bone mass and alleviate the onset of bone problems. This study aimed to investigate the beneficial effect of resistant starch from raw potato starch (RPS) on bone health in meat ducks. Response to the dietary graded level of RPS supplementation, both tibia strength and ash were taken out linear and quadratic increase and positively correlated with increased propionate and butyrate levels in cecal content. Moreover, further outcomes of gut microbiota and micro-CT analysis showed the beneficial effect of RPS on bone mass might be associated with higher Firmicutes proportion and the production of short-chain fatty acids (SCFAs) in the cecum. Consistent with improving bone mass, SCFAs promoted phosphorus absorption, decreased the digestive tract pH, and enhanced intestinal integrity, which decreased the expression of pro-inflammatory genes in both gut and bone marrow, and consequently depressed osteoclastic bone resorption mediated by inflammatory cytokines. These findings highlight the importance of the "gut-bone" axis and provide new insight into the effect of prebiotics on bone health.