Protective effect of agaro-oligosaccharides on gut dysbiosis and colon tumorigenesis in high-fat diet-fed mice

Abstract

High-fat diet (HFD)-induced alteration in the gut microbial composition, known as dysbiosis, is increasingly recognized as a major risk factor for various diseases, including colon cancer. This report describes a comprehensive investigation of the effect of agaro-oligosaccharides (AGO) on HFD-induced gut dysbiosis, including alterations in short-chain fatty acid contents and bile acid metabolism in mice. C57BL/6N mice were fed a control diet or HFD, with or without AGO. Terminal restriction fragment-length polymorphism (T-RFLP) analysis produced their fecal microbiota profiles. Profiles of cecal organic acids and serum bile acids were determined, respectively, using HPLC and liquid chromatography-tandem mass spectrometry systems. T-RFLP analyses showed that an HFD changed the gut microbiota significantly. Changes in the microbiota composition induced by an HFD were characterized by a decrease in the order Lactobacillales and by an increase in the Clostridium subcluster XIVa. These changes of the microbiota community generated by HFD treatment were suppressed by AGO supplementation. As supported by the data of the proportion of Lactobacillales order, the concentration of lactic acid increased in the HFD + AGO group. Data from the serum bile acid profile showed that the level of deoxycholic acid, a carcinogenic secondary bile acid produced by gut bacteria, was increased in HFD-receiving mice. The upregulation tended to be suppressed by AGO supplementation. Finally, results show that AGO supplementation suppressed the azoxymethane-induced generation of aberrant crypt foci in the colon derived from HFD-treated mice. Our results suggest that oral intake of AGO prevents HFD-induced gut dysbiosis, thereby inhibiting colon carcinogenesis.

Association of Intestinal Microbiota with Metabolic Markers and Dietary Habits in Patients with Type 2 Diabetes

“…These events ultimately lead to increased hepatic lipogenesis, and therefore the conversion of calories harvested from the diet into fat [28] . A high-fat diet has been shown to induce a change in microbial composition, characterized by decreases in order Lactobacillales and concomitant increases in Clostridium subcluster XIVa in mice [29] . In the present study, Clostridium subcluster XIVa was positively correlated with alanine aminotransferase and γ-glutamyltransferase levels, signifying that the amelioration of gut dysbiosis can help alleviate NAFLD in T2DM patients [30] .…”

Changes in Intestinal Motility and Gut Microbiota Composition in a Rat Stress Model

“…Each sample was suspended in lysis buffer (4- M guanidium thiocyanate, 100-m M Tris-HCl, and 40-m M EDTA and 0.001% bromothymol blue) and the samples were shaken in the presence of zirconia beads. Then, the DNA was extracted from the resultant suspensions using a Magtration System 12GC and GC series MagDEA DNA 200 (Precision System Science, Chiba, Japan) [12]. …”

The Relationship between Habitual Dietary Intake and Gut Microbiota in Young Japanese Women

“…Fecal samples were collected once in fecal collection tubes containing a guanidine thiocyanate solution (Techno Suruga Laboratory Co., Ltd., Japan) during the dietary survey period. Analysis of fecal microbiota by the T-RFLP method was outsourced to Techno Suruga Laboratory Co., Ltd. and performed according to a protocol described by previous reports (24). The abundance of each terminal restriction fragment (T-RF) was calculated by fi rst dividing it into 29 operational taxonomic units (OTUs) by the method described in Nagashima's reports (25,26).…”