Cyclic Nigerosylnigerose Attenuates High-Fat Diet-Induced Fat Deposition, Colonic Inflammation, and Abnormal Glucose Metabolism and Modifies Gut Immunoglobulin a Reactivity to Commensal Bacteria.

SCOPE: High-fat diet (HFD) intake induces gut dysbiosis, inflammation in the peripheral tissues, and a reduction in immunoglobulin A (IgA) coating of gut bacteria, which is related to HFD-induced insulin resistance (IR). This study evaluates the effect of cyclic nigerosylnigerose (CNN), a dietary fiber that prevents gut inflammation and promotes IgA coating of gut bacteria, on the above-mentioned HFD-induced disorders. METHODS AND RESULTS: Balb/c mice are fed an HFD and administered CNN for 20 weeks. CNN administration reduces mesenteric adipose tissue weight, colonic tumor necrosis factor α (TNFα) mRNA expression, and serum endotoxin levels and ameliorates HFD-induced abnormal glucose metabolism. Additionally, CNN administration promotes gut bacteria-specific IgA secretion and alters IgA reactivity to gut bacteria. The alterations of IgA reactivity to specific bacteria such as Erysipelatoclostridium, Escherichia, Faecalibaculum, Lachnospiraceae genera, and Stenotrophomonas are correlated with mesenteric adipose tissue weight, colonic TNFα mRNA expression, serum endotoxin levels, and a homeostasis model assessment for IR. CONCLUSION: CNN-induced alterations in IgA reactivity to gut bacteria may be related to the suppression of HFD-induced fat deposition, colonic inflammation, endotoxemia, and IR. These observations indicate that dietary fiber that modulates IgA reactivity to gut bacteria may be useful in preventing HFD-induced disorders.

Aicda deficiency exacerbates high-fat diet-induced hyperinsulinemia but not gut dysbiosis in mice.

Immunoglobulin A (IgA) is a major antibody in the gut. We previously observed that a high-fat diet (HFD) reduces IgA reactivity to gut microbiota, but the physiological implications have yet to be elucidated. We hypothesized that a reduction of IgA reactivity to gut microbiota induced by a HFD may contribute to development of gut dysbiosis and inflammation that accompanies HFD feeding. To test our hypothesis, we used Aicda deficient mice, which have a deficiency in IgA production. Aicda deficient mice and wild-type mice were fed normal-fat diet or HFD for 12 weeks. We found that HFD feeding but not Aicda deficiency altered the fecal microbiota composition. Meanwhile, Aicda deficiency significantly increased gene expression of inflammatory cytokines in the ileum, but not in the colon despite no significant difference between diets. These results suggest that a reduction of IgA reactivity to gut microbiota induced by HFD partly contributes to development of inflammation in the ileum, but not to gut dysbiosis. We also found that the fasting blood insulin level was significantly increased by Aicda deficiency only under HFD feeding. Furthermore, the gene expression of monocyte chemoattractant protein1, a major chemokine responsible for the onset of hyperinsulinemia, in the liver was significantly increased by HFD feeding and tended to be increased by Aicda deficiency. These findings suggest that a reduction of IgA reactivity to gut microbiota induced by HFD contributes to hyperinsulinemia partly via increasing monocyte chemoattractant protein-1 expression in the liver.

Examination of milk microbiota, fecal microbiota, and blood metabolites of Jersey cows in cool and hot seasons.

Microbiota of individual cow milk, bulk tank milk, and feces of Jersey cows were examined. Samples were collected from two farms (F1 and F2) in cool (November, Nov) and hot (July, Jul) seasons. Milk yield and milk composition were similar between the two farms and between the two seasons. Prevalent taxa of the fecal microbiota, i.e. Ruminococcaceae, Bacteroidaceae, Lachnospiraceae, Rikenellaceae, and Clostridiaceae, were unaffected by the farm and season. Relative abundance of milk microbiota for Pseudomonadaceae, Enterobacteriaceae, and Streptococcaceae (F1 > F2) and Lactobacillaceae, Bifidobacteriaceae, and Cellulomonadaceae (F1 < F2) were different between the two farms, and those for Staphylococcaceae, Bacillaceae, Ruminococcaceae, and Veillonellaceae (Nov < Jul) and Methylobacteriaceae and Moraxellaceae (Nov > Jul) were different between the two seasons. The microbiota of bulk tank milk was numerically different from that of individual cow milk. Principal coordinate analysis indicated that the milk microbiota was unrelated to the fecal microbiota. The finding that relative abundance of Pseudomonadaceae and Moraxellaceae appeared greater than those reported for Holstein milk suggested that higher protein and fat content may result in a greater abundance of proteolytic and lipolytic taxa in Jersey cow milk.

Rumen fluid, feces, milk, water, feed, airborne dust, and bedding microbiota in dairy farms managed by automatic milking systems.

Microbiota of the gut, milk, and cowshed environment were examined at two dairy farms managed by automatic milking systems (AMS). Feed, rumen fluid, feces, milk, bedding, water, and airborne dust were collected and the microbiota on each was assessed by Illumina MiSeq sequencing. The most abundant taxa in feed, rumen fluid, feces, bedding, and water were Lactobacillaceae, Prevotellaceae, Ruminococcaceae, Ruminococcaceae, and Lactobacillaceae, respectively, at both farms. Aerococcaceae was the most abundant taxon in milk and airborne dust microbiota at farm 1, and Staphylococcaceae and Lactobacillaceae were the most abundant taxa in milk and airborne dust microbiota at farm 2. The three most prevalent taxa (Aerococcaceae, Staphylococcaceae, and Ruminococcaceae at farm 1 and Staphylococcaceae, Lactobacillaceae, and Ruminococcaceae at farm 2) were shared between milk and airborne dust microbiota. Indeed, SourceTracker indicated that milk microbiota was related with airborne dust microbiota. Meanwhile, hierarchical clustering and canonical analysis of principal coordinates demonstrated that the milk microbiota was associated with the bedding microbiota but clearly separated from feed, rumen fluid, feces, and water microbiota. Although our findings were derived from only two case studies, the importance of cowshed management for milk quality control and mastitis prevention was emphasized at farms managed by AMS.