Glucerabacter canisensis gen. nov., sp. nov., isolated from dog feces and its effect on the hydrolysis of plant glucosylceramide in the intestine of dogs

Dietary Supplementation with Methylsulfonylmethane and Myo-Inosito Supports Hair Quality and Fecal Microbiome in Poodles

This study aimed to investigate the effects of dietary supplementation with methylsulfonylmethane (MSM) and myo-inositol (MI) on hair quality, fecal microbiota, and metabolome in poodles. Thirty-two adult poodles categorized based on initial body weight and sex were randomly assigned to four groups. These groups (designated the CON, MSM, MI, and MSM + MI groups) received a basal diet, the same diet supplemented with 0.2% MSM + 0% MI, the same diet supplemented with 0% MSM + 0.2% MI, or the same diet supplemented with 0.2% MSM + 0.2% MI, respectively. The study lasted for 65 days. During the entire study period, body weight, average daily weight gain, feed intake, energy intake, and fecal output were normal in all the animals and did not differ significantly among the treatment groups. Hair scale thickness was lower in the MI and MSM + MI groups than in the CON group on Day 65 (p < 0.05). An amino acid analysis of the hair revealed higher sulfur content in the MI and MSM + MI groups on Day 65 than on Day 0 (p < 0.05). Moreover, the poodles in the MSM, MI, and MSM + MI groups presented significantly lower levels of Proteobacteria_unclassified and Candidatus Phytoplasma than did those in the CON group. The relative abundance of Gammaproteobacteria_unclassified was greater in the MSM and MI groups than in the CON group (p < 0.05). The MSM group presented a greater abundance of Glucerabacter than the CON group (p < 0.05). Compared with those in the CON and MSM + MI groups, the abundances of Paramuribaculum and Hafnia in the MSM group were greater (p < 0.05). The abundances of Enterobacter and Kineothrix were greater (p < 0.05) in the MI group than in the CON and MSM + MI groups. The poodles in the MI group presented significantly greater abundances of Bacteroidales_unclassified, Halanaerobium, Mycobacterium, and Erysipelotrichaceae_unclassified than did poodles in the CON, MSM, and MSM + MI groups. Fecal metabolomics analysis revealed that MSM, MI, and MSM + MI treatment markedly affected carbohydrate metabolism. MSM + MI treatment also influenced lipid metabolism. These findings suggest that dietary supplementation with MSM and MI can improve the hair quality of poodles.

Effect of Dietary Ceramide and Glucosylceramide on the Alleviation of Experimental Inflammatory Bowel Disease in Mice

Ceramide prepared from glucosylceramide (GlcCer) with Gluceribacter canis NATH-2371^T was administrated to inflammatory bowel disease (IBD) model mice. Dietary ceramide significantly suppressed the decrease in final body weight, and the increase in the disease activity index and myeloperoxidase activity more greatly than GlcCer in IBD mice. Intestinal microbiome profiles were found to be altered in IBD mice, but ceramide counteracted the changes. These results suggest that dietary plant-based ceramide may alleviate symptoms of IBD in mice.

Glucosylceramide Changes Bacterial Metabolism and Increases Gram-Positive Bacteria through Tolerance to Secondary Bile Acids In Vitro

Glucosylceramide is present in many foods, such as crops and fermented foods. Most glucosylceramides are not degraded or absorbed in the small intestine and pass through the large intestine. Glucosylceramide exerts versatile effects on colon tumorigenesis, skin moisture, cholesterol metabolism and improvement of intestinal microbes in vivo. However, the mechanism of action has not yet been fully elucidated. To gain insight into the effect of glucosylceramide on intestinal microbes, glucosylceramide was anaerobically incubated with the dominant intestinal microbe, Blautia coccoides, and model intestinal microbes. The metabolites of the cultured broth supplemented with glucosylceramide were significantly different from those of broth not treated with glucosylceramide. The number of Gram-positive bacteria was significantly increased upon the addition of glucosylceramide compared to that in the control. Glucosylceramide endows intestinal microbes with tolerance to secondary bile acid. These results first demonstrated that glucosylceramide plays a role in the modification of intestinal microbes.

Augmentation of dietary glucosylceramide hydrolysis by the novel bacterium Glucerabacter canisensis NATH-2371T

The purpose of this study was to evaluate the effects of intragastrical administration of Glucerabacter canisensis NATH-2371^T on glucosylceramide (GluCer) digestion in mice. Although G. canisensis was unable to utilize starch and cellulose, coculture of G. canisensis with mouse fecal bacteria greatly increased GluCer hydrolysis in polysaccharide medium, indicating that G. canisensis grew in competition with other intestinal bacteria. Although most of the administered G. canisensis cells were detected in feces, some cells were present in the colorectum contents, which had GluCer-hydrolyzing activity. These results indicate that G. canisensis can viably transit through the mouse gut. Administration of G. canisensis to mice fed diets supplemented with GluCer or GluCer-containing foods significantly enhanced GluCer hydrolysis. Since G. canisensis did not show acute toxicity, it may be useful as a probiotic to augment GluCer hydrolysis in the large intestine. Abbreviations: GluCer: glucosylceramide; KPi: potassium phosphate buffer; C-M: chloroform-methanol.