Propensity to high-fat diet-induced obesity in mice is associated with the indigenous opportunistic bacteria on the interior of Peyer's patches

mbDecoda: a debiased approach to compositional data analysis for microbiome surveys

Potentially pathogenic or probiotic microbes can be identified by comparing their abundance levels between healthy and diseased populations, or more broadly, by linking microbiome composition with clinical phenotypes or environmental factors. However, in microbiome studies, feature tables provide relative rather than absolute abundance of each feature in each sample, as the microbial loads of the samples and the ratios of sequencing depth to microbial load are both unknown and subject to considerable variation. Moreover, microbiome abundance data are count-valued, often over-dispersed and contain a substantial proportion of zeros. To carry out differential abundance analysis while addressing these challenges, we introduce mbDecoda, a model-based approach for debiased analysis of sparse compositions of microbiomes. mbDecoda employs a zero-inflated negative binomial model, linking mean abundance to the variable of interest through a log link function, and it accommodates the adjustment for confounding factors. To efficiently obtain maximum likelihood estimates of model parameters, an Expectation Maximization algorithm is developed. A minimum coverage interval approach is then proposed to rectify compositional bias, enabling accurate and reliable absolute abundance analysis. Through extensive simulation studies and analysis of real-world microbiome datasets, we demonstrate that mbDecoda compares favorably with state-of-the-art methods in terms of effectiveness, robustness and reproducibility.

Probiotic interventions promote metabolic health in high fat-fed hamsters in association with gut microbiota and endocannabinoidome alterations

Probiotics represent a promising tool to improve metabolic health, including lipid profiles and cholesterol levels. Modulation of the gut microbiome and the endocannabinoidome - two interrelated systems involved in several metabolic processes influenced by probiotics - has been proposed as a potential mechanism of action. This study establishes the impact of probiotics on metabolic health, gut microbiota composition and endocannabinoidome mediators in an animal model of hypercholesterolaemia. Syrian hamsters were fed either a low-fat low-cholesterol or high-fat high-cholesterol (HFHC) diet to induce hypercholesterolaemia and gavaged for 6 weeks with either Lactobacillus acidophilus CL1285, Lactiplantibacillus plantarum CHOL-200 or a combination of the two. Globally, probiotic interventions ameliorated, at least partially, lipid metabolism in HFHC-fed hamsters. The interventions, especially those including L. acidophilus, modified the gut microbiota composition of the small intestine and caecum in ways suggesting reversal of HFHC-induced dysbiosis. Several associations were observed between changes in gut microbiota composition and endocannabinoidome mediators following probiotic interventions and both systems were also associated with improved metabolic health parameters. For instance, potential connexions between the Eubacteriaceae and Deferribacteraceae families, levels of 2‑palmitoylglycerol, 2‑oleoylglycerol, 2‑linoleoylglycerol or 2‑eicosapentaenoylglycerol and improved lipid profiles were found. Altogether, our results suggest a potential crosstalk between gut microbiota and the endocannabinoidome in driving metabolic benefits associated with probiotics, especially those including L. acidophilus, in an animal model of hypercholesterolaemia.

Effects of Coix Seed Extract, Bifidobacterium BPL1, and Their Combination on the Glycolipid Metabolism in Obese Mice

Coix seed extract (CSE) and probiotics have been reported to regulate glycolipid metabolism via different modes of action. We tested the effects of CSE, Bifidobacterium BPL1, and their combination to determine their effects on glycolipid metabolism in obese mice. Male C57BL/6J mice were fed a high-fat diet for 8 weeks to establish an obesity model. Obese mice were selected and divided into four groups: the model control group and three intervention groups. After 10 weeks of continuous gavage intervention, the mice in the intervention groups exhibited lower body weight (lower about 2.31 g, vs. HFD mice 42.23 g) and epididymal (lower about 0.37 g, vs. HFD mice 2.5 g) and perirenal fat content (lower about 0.47 g, vs. HFD mice 0.884 g); decreased fasting blood glucose, total cholesterol, triglycerides, and VLDL; and increased HLDL, respiratory exchange ratio, energy expenditure, and amount of exercise performed. CSE, BPL1 and their combination can effectively control the weight gain in obese mice, reduce fat content, and regulate blood lipids and abnormal blood sugar. These results may be related to reduce the chronic inflammatory states, improve energy metabolism, exercise, relieve insulin sensitivity, and reduce lipid synthesis via the intervention of CSE, BPL1 and their combination. Compared with the single use of CSE alone, the combination of CSE + BPL1 can better exert the regulation function of intestinal flora, and change in the abundance of bacteria that could improve the level of inflammatory factors, such as increasing Bifidobacterium, reducing Lactococcus. Compared with the use of BPL1 alone, the combination of CSE and BPL1 can better regulate pancreatic islet and improve blood sugar. CSE may act directly on body tissues to exert anti-inflammatory effects. BPL1 and CSE + BPL1 may improve the structure and function of the intestinal flora, and reduce tissue inflammation.

Altered Gut Microbiota in Patients With Peutz–Jeghers Syndrome

Background

Peutz–Jeghers syndrome (PJS) is a rare genetic disorder characterized by the development of pigmented spots and gastrointestinal polyps and increased susceptibility to cancers. It remains unknown whether gut microbiota dysbiosis is linked to PJS.

Aim

This study aimed to assess the structure and composition of the gut microbiota, including both bacteria and fungi, in patients with PJS and investigate the relationship between gut microbiota dysbiosis and PJS pathogenesis.

Methods

The bacterial and fungal composition of the fecal microbiota was analyzed in 23 patients with PJS (cases), 17 first-degree asymptomatic relatives (ARs), and 24 healthy controls (HCs) using 16S (MiSeq) and ITS2 (pyrosequencing) sequencing for bacteria and fungi, respectively. Differential analyses of the intestinal flora were performed from the phylum to species level.

Results

Alpha-diversity distributions of bacteria and fungi indicated that the abundance of both taxa differed between PJS cases and controls. However, while the diversity and composition of fecal bacteria in PJS cases were significantly different from those in ARs and HCs, fungal flora was more stable. High-throughput sequencing confirmed the special characteristics and biodiversity of the fecal bacterial and fungal microflora in patients with PJS. They had lower bacterial biodiversity than controls, with a higher frequency of the Proteobacteria phylum, Enterobacteriaceae family, and Escherichia-Shigella genus, and a lower frequency of the Firmicutes phylum and the Lachnospiraceae and Ruminococcaceae families. Of fungi, Candida was significantly higher in PJS cases than in controls.

Conclusion

The findings reported here confirm gut microbiota dysbiosis in patients with PJS. This is the first report on the bacterial and fungal microbiota profile of subjects with PJS, which may be meaningful to provide a structural basis for further research on intestinal microecology in PJS.

Beneficial effects of Gynostemma pentaphyllum honey paste on obesity via counteracting oxidative stress and inflammation: An exploration of functional food developed from two independent foods rich in saponins and phenolics

The development of functional foods that possess a combination of biological functions and good sensory properties is an emerging topic in the field of food and function. Gynostemma pentaphyllum (G. pentaphyllum) is widely considered to exert anti-obesity effect owing to its abundant saponins and other bioactive components, but bitter and unacceptable taste limit its utilization. While honey, a natural sweetener, not only has the pleasure sense but is also usually used as the carrier of functional food due to its phenolic oligosaccharide, etc. In the present study, we proposed the preparation method of a G. pentaphyllum honey paste (GH) and its beneficial effects on obese mice. The results showed that GH contented 0.055 mg/g Gypenoside XLIX, 0.01 mg/g Gypenoside A, and 11 kinds of phenolics. It could down-regulate 23.3% of liver TC level, increase serum ALT activity, improve liver tissue damage and epididymal adipocyte hypertrophy than obese mice. Besides, GH regulated enzyme activities such as SOD and GSH to enhance oxidative stress defense and exerted anti-inflammatory activity via IL-6 (52.4%), TNF-α (38.7%), IFN-γ (32%) and NF-κB (28%) genes down-regulation, which also reshaped the gut microbiota structure, exerting anti-obesity effects. More importantly, GH promoted obese mice appetite with orexin-A compared to G. pentaphyllum alone. This study provided a new perspective on the development of G. pentaphyllum functional foods with both good organoleptic performance and obesity therapy.

The Application of Copper Waterline on Laying Performance and Gut Health of Aged Laying Hens

The effect of the application of copper waterline on the performance and gut health of aged laying hens was evaluated in this study. Forty-eight 70-week-old laying hens were divided into two groups (three replicates of eight hens each): control and copper (Cu) groups provided with normal polyvinyl chloride (PVC) waterline or Cu waterline. The laying performance was measured during the four-week period of the experiment. The intestinal antioxidant status and the microbiota diversity of the cecal content were determined. Moreover, a bacteriostasis test on Escherichia coli and Salmonella enteritidis was conducted after inoculation in waterline and hens, respectively. The water Cu²⁺ content was increased by Cu waterline compared to the control (P<0.05). Cu waterline had no detectable effect on most production performances, however, it increased the egg weight (P<0.05). Cu waterline increased the Cu level in the eggshell. Cu level in excreta increased with time, especially in the final two weeks, however, there was no significant change in fecal Cu excretion. The lipid peroxidation product malondialdehyde content in ileum decreased (P<0.01), while the activities of CuZn-superoxide dismutase (SOD) of ileum and glutathione peroxidase (GSH-PX) activity of jejunum and ileum increased after Cu treatment. The relative abundance and richness of cecal microbiota increased after Cu treatment (P<0.05). Cu waterline changed the microbial composition, including the increased proportion of Methanocorpusculum, Paludibacter, and decreased proportion of Fucobacterium, Anaerobiospirillum, and Campylobacter. The colonization of E. coli and S. enteritidis in Cu waterline was suppressed by Cu treatment, indicating that Cu waterline had potential antibacterial properties. The result suggests that Cu waterline could inhibit the colonization of pathogenic microorganisms such as E. coli and Salmonella and facilitate the enrichment of cecal microbiota diversity.

The Main Anthocyanin Monomer from Lycium ruthenicum Murray Fruit Mediates Obesity via Modulating the Gut Microbiota and Improving the Intestinal Barrier

Anthocyanins have been shown to exert certain antiobesity properties, but the specific relationship between anthocyanin-induced beneficial effects and the gut microbiota remains unclear. Petunidin-3-O-[rhamnopyranosyl-(trans-p-coumaroyl)]-5-O-(β-D-glucopyranoside) (P3G) is the main anthocyanin monomer from the fruit of Lycium ruthenicum Murray. Therefore, in this study, we investigated the antiobesity and remodeling effects of P3G on gut microbiota through a high-fat diet (HFD)-induced obesity mouse model and a fecal microbiota transplantation experiment. P3G was found to reduce body weight gain, fat accumulation, and liver steatosis in HFD-induced obese mice. Moreover, supplementation with P3G alleviated the HFD-induced imbalance in gut microbiota composition, and transferring the P3G-regulated gut microbiota to recipient mice provided comparable protection against obesity. This is the first time evidence is provided that P3G has an antiobesity effect by changing the intestinal microbiota. Our present data highlight a link between P3G intervention and enhancement in gut barrier integrity. This may be a promising option for obesity prevention.

The Synbiotic Combination of Akkermansia muciniphila and Quercetin Ameliorates Early Obesity and NAFLD through Gut Microbiota Reshaping and Bile Acid Metabolism Modulation

Gut microbiota plays a key role in obesity and non-alcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. We aim to evaluate a nutritional intervention together with the administration of the bacteria Akkermansia muciniphila and the antioxidant quercetin in an in vivo model of early obesity and NAFLD. 21-day-old rats were fed with control or high-fat diet for six weeks. Then, all animals received control diet supplemented with/without quercetin and/or A. muciniphila for three weeks. Gut microbiota, NAFLD-related parameters, circulating bile acids (BAs) and liver gene expression were analyzed. The colonization with A. muciniphila was associated with less body fat, while synbiotic treatment caused a steatosis remission, linked to hepatic lipogenesis modulation. The synbiotic promoted higher abundance of Cyanobacteria and Oscillospira, and lower levels of Actinobacteria, Lactococcus, Lactobacillus and Roseburia. Moreover, it favored elevated unconjugated hydrophilic BAs plasma levels and enhanced hepatic expression of BA synthesis and transport genes. A. muciniphila correlated with circulating BAs and liver lipid and BA metabolism genes, suggesting a role of this bacterium in BA signaling. Beneficial effects of A. muciniphila and quercetin combination are driven by gut microbiota modulation, the shift in BAs and the gut-liver bile flow enhancement.

Effects of dicopper oxide and copper sulfate on growth performance and gut microbiota in broilers

An experiment was conducted to determine the effects of two sources of copper (Cu) from copper sulfate (CuSO4) and dicopper oxide (Cu2O, CoRouge) at three levels of inclusion (15, 75, and 150 mg/kg) on growth performance and gut microbiota of broilers. A total of 840 one-d-old male chickens (Ross 308) were weighed and randomly allocated to seven dietary treatments: negative control (NC, a basal diet without Cu addition), and the NC supplemented with 15, 75, or 150 mg Cu/kg from CuSO4 or Cu2O (12 replicate pens/treatment, 10 chicks per pen). Broilers were challenged by reusing an old litter with high concentrations in Clostridium perfringens to promote necrotic enteritis. Broiler performance was registered at d 21, 35, and 42. Excreta samples were collected at d 14, 28, and 42 for antimicrobial resistance (AMR) analyses. At d 43, one broiler per pen was euthanized to obtain ileal content for microbial characterization. Body weight d 35 and daily gain d 42 improved (P < 0.05) in Cu2O as Cu dose inclusion increased from 15 mg/kg to 150 mg/kg. Supplementation of 150 mg/kg of Cu from Cu2O decreased the abundance (P < 0.01) of some families such as Streptococcaceae and Corynebacteriaceae and increased the abundance (P < 0.05) of some commensal bacteria like Clostridiaceae and Peptostreptococcaceae. Phenotypic AMR was not different among treatments on d 14 and 28. Isolated Enterococcus spp. from broilers fed the NC diet on d 42 showed higher (P < 0.05) resistance to enrofloxacin, gentamicin, and chloramphenicol compared with Cu treatments. By contrast, the isolated Escherichia coli from broilers fed 150 mg/kg of Cu, either from CuSO4 or Cu2O, showed higher (P < 0.05) resistance to streptomycin and chloramphenicol compared to the NC. This study suggests that supplementing 150 mg/kg of Cu from Cu2O establishes changes in the gut microbiota by regulating the bacterial population in the ileum, which may explain the positive impact on broilers' growth performance.

Blueberry and cranberry anthocyanin extracts reduce bodyweight and modulate gut microbiota in C57BL/6 J mice fed with a high-fat diet

PURPOSE

Blueberry and cranberry are rich in anthocyanins. The present study was to investigate the effects of anthocyanin extracts from blueberry and cranberry on body weight and gut microbiota.

METHODS

C57BL/6 J Mice were divided into six groups (n = 9 each) fed one of six diets namely low-fat diet (LFD), high-fat diet (HFD), HFD with the addition of 1% blueberry extract (BL), 2% blueberry extract (BH), 1% cranberry extract (CL), and 2% cranberry extract (CH), respectively.

RESULTS

Feeding BL and BH diets significantly decreased body weight gain by 20-23%, total adipose tissue weight by 18-20%, and total liver lipids by 16-18% compared with feeding HFD. Feeding CH diet but not CL diet reduced the body weight by 27%, accompanied by a significant reduction of total plasma cholesterol by 25% and tumor necrosis factor alpha (TNF-α) by 38%. The metagenomic analysis showed that the supplementation of blueberry and cranberry anthocyanin extracts reduced plasma lipopolysaccharide concentration, accompanied by a reduction in the relative abundance of Rikenella and Rikenellaceae. Dietary supplementation of berry anthocyanin extracts promoted the growth of Lachnoclostridium, Roseburia, and Clostridium_innocuum_group in genus level, leading to a greater production of fecal short-chain fatty acids (SCFA).

CONCLUSIONS

It was concluded that both berry anthocyanins could manage the body weight and favorably modulate the gut microbiota at least in mice.

Allium-Derived Compound Propyl Propane Thiosulfonate (PTSO) Attenuates Metabolic Alterations in Mice Fed a High-Fat Diet through Its Anti-Inflammatory and Prebiotic Properties

Background: Propyl propane thiosulfonate (PTSO) is an organosulfur compound from Allium spp. that has shown interesting antimicrobial properties and immunomodulatory effects in different experimental models. In this sense, our aim was to evaluate its effect on an experimental model of obesity, focusing on inflammatory and metabolic markers and the gut microbiota. Methods and results: Mice were fed a high-fat diet and orally treated with different doses of PTSO (0.1, 0.5 and 1 mg/kg/day) for 5 weeks. PTSO lessened the weight gain and improved the plasma markers associated with glucose and lipid metabolisms. PTSO also attenuated obesity-associated systemic inflammation, reducing the immune cell infiltration and, thus, the expression of pro-inflammatory cytokines in adipose and hepatic tissues (Il-1ẞ, Il-6, Tnf-α, Mcp-1, Jnk-1, Jnk-2, Leptin, Leptin R, Adiponectin, Ampk, Ppar-α, Ppar-γ, Glut-4 and Tlr-4) and improving the expression of different key elements for gut barrier integrity (Muc-2, Muc-3, Occludin, Zo-1 and Tff-3). Additionally, these effects were connected to a regulation of the gut microbiome, which was altered by the high-fat diet. Conclusion: Allium-derived PTSO can be considered a potential new tool for the treatment of metabolic syndrome.

Long-Term Effects of Bariatric Surgery on Gut Microbiota Composition and Faecal Metabolome Related to Obesity Remission

Obesity is one of the main worldwide public health concerns whose clinical management demands new therapeutic approaches. Bariatric surgery is the most efficient treatment when other therapies have previously failed. Due to the role of gut microbiota in obesity development, the knowledge of the link between bariatric surgery and gut microbiota could elucidate new mechanistic approaches. This study aims to evaluate the long-term effects of bariatric surgery in the faecal metagenome and metabolome of patients with severe obesity. Faecal and blood samples were collected before and four years after the intervention from patients with severe obesity. Biochemical, metagenomic and metabolomic analyses were performed and faecal short-chain fatty acids were measured. Bariatric surgery improved the obesity-related status of patients and significantly reshaped gut microbiota composition. Moreover, this procedure was associated with a specific metabolome profile characterized by a reduction in energetic and amino acid metabolism. Acetate, butyrate and propionate showed a significant reduction with bariatric surgery. Finally, correlation analysis suggested the existence of a long-term compositional and functional gut microbiota profile associated with the intervention. In conclusion, bariatric surgery triggered long-lasting effects on gut microbiota composition and faecal metabolome that could be associated with the remission of obesity.

Dietary fat and low fiber in purified diets differently impact the gut-liver axis to promote obesity-linked metabolic impairments

Selecting the most relevant control diet is of critical importance for metabolic and intestinal studies in animal models. Chow and LF-purified diet differentially impact metabolic and gut microbiome outcomes resulting in major changes in intestinal integrity in LF-fed animals which contributes to altering metabolic homeostasis. Dietary fat and low fiber both contribute to the deleterious metabolic effect of purified HF diets through both selective and overlapping mechanisms.

Depletion of the gut microbiota differentially affects the impact of whey protein on high-fat diet-induced obesity and intestinal permeability

Whey protein isolate (WPI) is considered a dietary solution to obesity. However, the exact mechanism of WPI action is still poorly understood but is probably connected to its beneficial effect on energy balance, adiposity, and metabolism. More recently its ability to modulate the gut microbiota has received increasing attention. Here, we used a microbiota depletion, by antibiotic cocktail (ABX) administration, to investigate if the gut microbiota mediates the physiological and metabolic changes observed during high-fat diet (HFD)-WPI consumption. C57BL/6J mice received a HFD containing WPI (HFD-WPI) or the control non-whey milk protein casein (HFD-CAS) for 5 or 10 weeks. HFD-fed mice supplemented with WPI showed reduced body weight gain, adiposity, Ob gene expression level in the epidydimal adipose tissue (eWAT) and plasma leptin relative to HFD-CAS-fed mice, after 5- or 10-weeks intervention both with or without ABX treatment. Following 10-weeks intervention, ABX and WPI had an additive effect in lowering adiposity and leptin availability. HFD-WPI-fed mice showed a decrease in the expression of genes encoding pro-inflammatory markers (MCP-1, TNFα and CD68) within the ileum and eWAT, compared to HFD-CAS-fed mice, without showing alterations following microbiota depletion. Additionally, WPI supplementation decreased HFD-induced intestinal permeability disruption in the distal ileum; an effect that was reversed by chronic ABX treatment. In summary, WPI reverses the effects of HFD on metabolic and physiological functions through mainly microbiota-independent mechanisms. Moreover, we demonstrate a protective effect of WPI on HFD-induced inflammation and ileal permeability disruption, with the latter being reversed by gut microbiota depletion.

Nutrient-imbalanced conditions shift the interplay between zooplankton and gut microbiota

Background

Nutrient stoichiometry of phytoplankton frequently changes with aquatic ambient nutrient concentrations, which is mainly influenced by anthropogenic water treatment and the ecosystem dynamics. Consequently, the stoichiometry of phytoplankton can markedly alter the metabolism and growth of zooplankton. However, the effects of nutrient-imbalanced prey on the interplay between zooplankton and their gut microbiota remain unknown. Using metatranscriptome, a 16 s rRNA amplicon-based neutral community model (NCM) and experimental validation, we investigated the interactions between Daphnia magna and its gut microbiota in a nutrient-imbalanced algal diet.

Results

Our results showed that in nutrient-depleted water, the nutrient-enriched zooplankton gut stimulated the accumulation of microbial polyphosphate in fecal pellets under phosphorus limitation and the microbial assimilation of ammonia under nitrogen limitation. Compared with the nutrient replete group, both N and P limitation markedly promoted the gene expression of the gut microbiome for organic matter degradation but repressed that for anaerobic metabolisms. In the nutrient limited diet, the gut microbial community exhibited a higher fit to NCM (R² = 0.624 and 0.781, for N- and P-limitation, respectively) when compared with the Control group (R² = 0.542), suggesting increased ambient-gut exchange process favored by compensatory feeding. Further, an additional axenic grazing experiment revealed that the growth of D. magna can still benefit from gut microbiota under a nutrient-imbalanced diet.

Conclusions

Together, these results demonstrated that under a nutrient-imbalanced diet, the microbes not only benefit themselves by absorbing excess nutrients inside the zooplankton gut but also help zooplankton to survive during nutrient limitation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-020-07333-z.

Catalpol ameliorates diabetes-induced testicular injury and modulates gut microbiota

AIMS

To explore the mechanisms of diabetes mellitus (DM)-induced testicular injury caused by modulation of testicular glycolysis and gut microbiota (GM), and evaluation of the efficacy of catalpol in reversing testicular morbidity.

MAIN METHODS

A model of DM-induced testicular injury was established using a high-fat diet in KK-Ay mice. Microbial communities in the feces of mice in normal, model and catalpol (Cat) groups were analyzed by 16S gene sequencing. Correlations between the GM and lactate metabolism levels, lactate dehydrogenase activity, and indicators of testicular injury were analyzed.

KEY FINDINGS

Cat significantly reduced general indicators of diabetes in mice with DM-induced reproductive injury, mitigated damage to the testicular tissue, and increased sperm count and motility. Additionally, the levels of products of glycolysis metabolism (e.g. lactate) increased following Cat treatment compared with the Model group. Disorders in the GM were also reversed in the Cat group.

SIGNIFICANCE

Cat ameliorated DM-induced testicular injury in KK-Ay mice by increasing the energy available to germ cells through glycolysis, principally through modulation of the GM and a reduction in the quantities of associated pathogenic bacteria.

Gut microbiota-mediated xanthine metabolism is associated with resistance to high-fat diet-induced obesity

Resistance to high-fat diet-induced obesity (DIR) has been observed in mice fed a high-fat diet and may provide a potential approach for anti-obesity drug discovery. However, the metabolic status, gut microbiota composition, and its associations with DIR are still unclear. Here, ultraperformance liquid chromatography-tandem mass spectrometry-based urinary metabolomic and 16S rRNA gene sequencing-based fecal microbiome analyses were conducted to investigate the relationship between metabolic profile, gut microbiota composition, and body weight of C57BL/6J mice on chow or a high-fat diet for 8 weeks. PICRUSt analysis of 16S rRNA gene sequences predicted the functional metagenomes of gut bacteria. The results demonstrated that feeding a high-fat diet increased body weight and fasting blood glucose of high-fat diet-induced obesity (DIO) mice and altered the host-microbial co-metabolism and gut microbiota composition. In DIR mice, high-fat diet did not increase body weight while fasting blood glucose was increased significantly compared to chow fed mice. In DIR mice, the urinary metabolic pattern was shifted to a distinct direction compared to DIO mice, which was mainly contributed by xanthine. Moreover, high-fat diet caused gut microbiota dysbiosis in both DIO and DIR mice, but in DIR mice, the abundance of Bifidobacteriaceae, Roseburia, and Escherichia was not affected compared to mice fed a chow diet, which played an important role in the pathway coverage of FormylTHF biosynthesis I. Meanwhile, xanthine and pathway coverage of FormylTHF biosynthesis I showed significant positive correlations with mouse body weight. These findings suggest that gut microbiota-mediated xanthine metabolism correlates with resistance to high-fat DIO.

The influence of wasabi on the gut microbiota of high-carbohydrate, high-fat diet-induced hypertensive Wistar rats

The human gut microbiota plays a critical role in the regulation of adiposity, obesity and metabolic and cardiovascular disease. Wasabi is a pungent spice and its active component, allyl isothiocyanate, improves plasma triacylglycerol, cholesterol and high blood pressure in rodents, but it is unclear if this occurs through alterations to the composition of the microbiota. The aim of this study was to determine the effectiveness of Wasabi japonica stem and rhizome blend on ameliorating cardiovascular disease parameters including plasma sodium concentration, systolic blood pressure (SBP), plasma endothelin-1 and angiotensin II concentrations by altering the gut microbiota in a Wistar rat model of obesity and metabolic syndrome. Rats were randomized to receive a corn starch or high-carbohydrate/high-fat diet for 8 weeks before being allocated to supplementation with wasabi powder (5% (w/w) in food) or not for an additional 8 weeks. At the end of the trial, rats were grouped according to blood pressure status. Wasabi supplementation prevented the development of hypertension and was also associated with significantly increased abundance of Allobaculum, Sutterella, Uncl. S247, Uncl. Coriobacteriaceae and Bifidobacterium. Hypertension was positively correlated with higher abundance of Oscillospira, Uncl. Lachnospiraceae and Uncl. Clostridiales, Uncl. Bacteroidales and Butyricimonas. Oscillospira and Butyricimonas abundances were specifically positively correlated with systolic blood pressure. Overall, the improved host cardiovascular health in diet-induced obese rats supplemented with wasabi powder may involve changes to the gut microbiota composition.

Therapeutic effects of noni fruit water extract and polysaccharide on oxidative stress and inflammation in mice under high-fat diet

This study aims to compare the therapeutic effects of noni fruit water extract (NFW) and noni fruit polysaccharide (NFP) on oxidative stress and inflammation in mice under high-fat diet.

Lactobacillus casei-fermented blueberry pomace augments sIgA production in high-fat diet mice by improving intestinal microbiota

Intestinal secretory immunoglobulin A (sIgA)-improving function of Lactobacillus casei-fermented blueberry pomace (FBP) was investigated in this study.

Low-fat/high-fibre diet prehabilitation improves anastomotic healing via the microbiome: an experimental model

BACKGROUND

Both obesity and the presence of collagenolytic bacterial strains (Enterococcus faecalis) can increase the risk of anastomotic leak. The aim of this study was to determine whether mice chronically fed a high-fat Western-type diet (WD) develop anastomotic leak in association with altered microbiota, and whether this can be mitigated by a short course of standard chow diet (SD; low fat/high fibre) before surgery.

METHODS

Male C57BL/6 mice were assigned to either SD or an obesogenic WD for 6 weeks followed by preoperative antibiotics and colonic anastomosis. Microbiota were analysed longitudinally after operation and correlated with healing using an established anastomotic healing score. In reiterative experiments, mice fed a WD for 6 weeks were exposed to a SD for 2, 4 and 6 days before colonic surgery, and anastomotic healing and colonic microbiota analysed.

RESULTS

Compared with SD-fed mice, WD-fed mice demonstrated an increased risk of anastomotic leak, with a bloom in the abundance of Enterococcus in lumen and expelled stool (65-90 per cent for WD versus 4-15 per cent for SD; P = 0·010 for lumen, P = 0·013 for stool). Microbiota of SD-fed mice, but not those fed WD, were restored to their preoperative composition after surgery. Anastomotic healing was significantly improved when WD-fed mice were exposed to a SD diet for 2 days before antibiotics and surgery (P < 0·001).

CONCLUSION

The adverse effects of chronic feeding of a WD on the microbiota and anastomotic healing can be prevented by a short course of SD in mice. Surgical relevance Worldwide, enhanced recovery programmes have developed into standards of care that reduce major complications after surgery, such as surgical-site infections and anastomotic leak. A complementary effort termed prehabilitation includes preoperative approaches such as smoking cessation, exercise and dietary modification. This study investigated whether a short course of dietary prehabilitation in the form of a low-fat/high-fibre composition can reverse the adverse effect of a high-fat Western-type diet on anastomotic healing in mice. Intake of a Western-type diet had a major adverse effect on both the intestinal microbiome and anastomotic healing following colonic anastomosis in mice. This could be reversed when mice received a low-fat/high-fibre diet before operation. Taken together, these data suggest that dietary modifications before major surgery can improve surgical outcomes via their effects on the intestinal microbiome.

Microbial fermentation of flaxseed fibers modulates the transcriptome of GPR41-expressing enteroendocrine cells and protects mice against diet-induced obesity

Dietary fibers, an integral part of the human diet, require the enzymatic activity of the gut microbiota for complete metabolism into short-chain fatty acids (SCFAs). SCFAs are important modulators of host metabolism and physiology and act in part as signaling molecules by activating G protein-coupled receptors (GPCRs), such as GPR41. Flaxseed fibers improve metabolism in rodents and mice, but their fermentation profiles, effects on enteroendocrine cells, and associated metabolic benefits are unknown. We fed GPR41-red fluorescent protein mice, an enteroendocrine reporter mouse strain, chow, high-fat diet (HFD), or HFD supplemented either with 10% nonfermentable fiber cellulose or fermentable flaxseed fibers for 12 wk to assess changes in cecal gut microbiota, enteroendocrine cell transcriptome in the ileum and colon, and physiological parameters. We observed that flaxseed fibers restructured the gut microbiota and promoted proliferation of the genera Bifidobacterium and Akkermansia compared with HFD. The shifts in cecal bacterial composition restored levels of the SCFAs butyrate similar to the chow diet, resulting in colonic but not ileal enteroendocrine cell transcriptional changes in genes related to cell cycle, mRNA, and protein transport compared with HFD. Consistent with the effects on enteroendocrine functions, flaxseed fibers also protected mice from diet-induced obesity, potentially by preventing a reduction in energy expenditure induced by an HFD. Our study shows that flaxseed fibers alter cecal microbial ecology, are fermented to SCFAs in the cecum, and modulate enteroendocrine cell transcriptome in the colon, which may contribute to their metabolically favorable phenotype.

Sustained Captopril-Induced Reduction in Blood Pressure Is Associated With Alterations in Gut-Brain Axis in the Spontaneously Hypertensive Rat

Background We have demonstrated that the antihypertensive effect of the angiotensin-converting enzyme inhibitor, captopril ( CAP ), is associated with beneficial effects on gut pathology. Coupled with the evidence that CAP exerts prolonged reduction in blood pressure ( BP ) after discontinuation of treatment, we investigate whether persistent beneficial actions of CAP are linked to alterations of gut microbiota and improvement of hypertension-induced gut pathology. Methods and Results Spontaneously hypertensive rats ( SHR ) and Wistar Kyoto rats were treated with CAP (250 mg/kg/day) for 4 weeks followed by withdrawal for 16 weeks. Gut microbiota, gut pathology, BP, and brain neuronal activity were assessed. CAP resulted in a ≈60 mm Hg decrease in systolic BP after 3 weeks of treatment in SHR , and the decrease remained significant at least 5 weeks after CAP withdrawal. In contrast, CAP caused modest decrease in systolic BP in Wistar Kyoto. 16S rRNA gene-sequencing-based gut microbial analyses in SHR showed sustained alteration of gut microbiota and increase in Allobaculum after CAP withdrawal. Phylogenetic investigation of communities by reconstruction of unobserved states analysis revealed significant increase in bacterial sporulation upon CAP treatment in SHR . These were associated with persistent improvement in gut pathology and permeability. Furthermore, manganese-enhanced magnetic resonance imaging showed significantly decreased neuronal activity in the posterior pituitary of SHR 4 weeks after withdrawal. Conclusions Decreased BP , altered gut microbiota, improved gut pathology and permeability, and dampened posterior pituitary neuronal activity were maintained after CAP withdrawal in the SHR . They suggest that CAP influences the brain-gut axis to maintain the sustained antihypertensive effect of CAP after withdrawal.

High-fat diet reduces the level of secretory immunoglobulin A coating of commensal gut microbiota

Excessive fat intake is associated with changes in gut microbiota composition. In the present study, we focused on the secretory immunoglobulin A (SIgA) coating of gut microbiota as a mucosal immune response affecting the gut microbiota following a high-fat diet (HFD). The level of SIgA coating of gut microbiota was evaluated in normal-fat diet (NFD)- and HFD-fed mice. HFD significantly decreased the level of SIgA coating the gut microbiota compared with NFD. Of note, substitution of HFD with NFD resulted in a complete recovery of the level of SIgA coating. These findings suggest that dietary fat influences the SIgA coating of the gut microbiota. Furthermore, we analyzed the composition of the gut microbiota and the concentration of cecal short-chain fatty acids. HFD feeding changed the gut microbiota composition at the phylum and family levels. Pearson correlation analysis between the level of SIgA coating of gut microbiota and the relative abundance of gut microbiota showed that the relative abundances of Clostridiaceae, Mogibacteriaceae, Turicibacteraceae, and Bifidobacteriaceae were negatively correlated with the level of SIgA coating of gut microbiota. Conversely, the relative abundances of Desulfovibrionaceae, S24-7, and Lactobacillaceae were positively correlated with the level of SIgA coating. The concentrations of cecal acetate and butyrate were lower in HFD-fed mice and positively correlated with the level of SIgA coating of gut microbiota. Our observations suggest that a decrease in the level of SIgA coating of the gut microbiota through a HFD might relate to HFD-induced changes in microbial composition and microbial metabolites production.

Effect of Taurine on Intestinal Microbiota and Immune Cells in Peyer's Patches of Immunosuppressive Mice

Taurine is a sulfur-containing amino acid which has strong activities in enhancing immunity. Gut microbiota is closely interrelated with intestinal mucosal immunity, but the effects and mechanisms of taurine on intestinal microbiota and mucosal immune cells under an immunosuppressive condition remain unclear. This study was conducted to investigate the effect of taurine on gut microbiota and immune cells in Peyer's patches (PPs) of dexamethasone (Dex)-induced immunosuppressive mice. Mice (4-week-old, Male) were randomly divided into three groups: the Control group (n = 12), the Dex-induced immunosuppressive model group (n = 12) and the taurine intervention group (n = 12). The model was established by Dex injection for 7 days and the taurine intervention group was gavaged 100 mg/kg soluble taurine for 30 days. The changes of intestinal microbiota and immune cells in PPs were tested by denaturing gradient gel electrophoresis (DGGE) and flow cytometry, respectively. Results showed that the microbiota in immunosuppressive mice was obvious different compared with control group, in which, the Lachnospiraceae and Ruminococcaceae groups were significantly reduced, and their reduction were reversed after taurine intervention. Compared to the control group, the total cell number in PPs, as well as the subsets of CD3⁺ cells (T cells), CD19⁺ cells (B cells) in model groups were significantly lower, and they were dramatically improved after taurine treatment. Our results suggested that taurine has a positive effect on i ntestinal homeostasis of the immunosuppressive mice.

Supplementation of Lactobacillus plantarum Improves Markers of Metabolic Dysfunction Induced by a High Fat Diet

Obesity is a prevalent chronic condition in many developed and developing nations that raises the risk for developing heart disease, stroke, and diabetes. Previous studies have shown that consuming particular probiotic strains of Lactobacillus is associated with improvement in the obese and diabetic phenotype; however, the mechanisms of these beneficial effects are not well understood. In this study, C57BL/6J male mice were fed a lard-based high fat diet for 15 weeks with Lactobacillus plantarum supplementation NCIMB8826 (Lp) between weeks 10 and 15 ( n = 10 per group). Systemic metabolic effects of supplementation were analyzed by NMR metabolomics, protein expression assays, gene transcript quantification, and 16S rRNA marker gene sequencing. Body and organ weights were not significantly different with Lp supplementation, and no microbiota community structure changes were observed in the cecum; however, L. plantarum numbers were increased in the treatment group according to culture-based and 16S rRNA gene quantification. Significant differences in metabolite and protein concentrations (serum, liver, and colon), gene expression (ileum and adipose), and cytokines (colon) were observed between groups with increases in the gene expression of tight junction proteins in the ileum and cecum and improvement of some markers of glucose homeostasis in blood and tissue with Lp supplementation. These results indicate Lp supplementation impacts systemic metabolism and immune signaling before phenotypic changes and without large-scale changes to the microbiome. This study supports the notion that Lp is a beneficial probiotic, even in the context of a high fat diet.

Genetic ablation of Cyp8b1 preserves host metabolic function by repressing steatohepatitis and altering gut microbiota composition

Both type 2 diabetes (T2D) and nonalcoholic steatohepatitis (NASH) are associated with reduced hepatic mitochondrial respiratory capacity. Cholic acid (CA) is the predominant 12α-hydroxylated bile acid that regulates hepatic lipid metabolism, and its circulating levels are negatively correlated with insulin resistance. Abolishing CA synthesis via the genetic disruption of the enzyme sterol 12α-hydroxylase ( Cyp8b1^-/-) leads in resistance to diabetes and hepatic steatosis. Here, we show that long-term stimulation of hepatic lipogenesis leads to a severe impairment in overall metabolic and respiratory function in control mice ( Cyp8b1^+/+) but strikingly not in Cyp8b1^-/- mice. Cyp8b1^-/- mice are protected from such metabolic impairments associated with T2D and NASH by inhibiting hepatic de novo lipogenic gene and protein expression and altering gut microbiota composition. The protective phenotype is compromised when NASH induction is independent of impairment in de novo lipogenesis (DNL). Consequently, Cyp8b1^-/- mice also show a reduction in hepatic inflammation and fibrosis along with a shift in antimicrobial dynamics in the small intestine. Our data show that the altered bile acid composition of Cyp8b1^-/- mice preserves metabolic and respiratory function by repressing hepatic DNL and driving favorable changes in gut antimicrobial responses.

Gut microbiome may contribute to insulin resistance and systemic inflammation in obese rodents: a meta-analysis

A number of studies have associated obesity with altered gut microbiota, although results are discordant regarding compositional changes in the gut microbiota of obese animals. Herein we used a meta-analysis to obtain an unbiased evaluation of structural and functional changes of the gut microbiota in diet-induced obese rodents. The raw sequencing data of nine studies generated from high-fat diet (HFD)-induced obese rodent models were processed with QIIME to obtain gut microbiota compositions. Biological functions were predicted and annotated with KEGG pathways with PICRUSt. No significant difference was observed for alpha diversity and Bacteroidetes-to-Firmicutes ratio between obese and lean rodents. Bacteroidia, Clostridia, Bacilli, and Erysipelotrichi were dominant classes, but gut microbiota compositions varied among studies. Meta-analysis of the nine microbiome data sets identified 15 differential taxa and 57 differential pathways between obese and lean rodents. In obese rodents, increased abundance was observed for Dorea, Oscillospira, and Ruminococcus, known for fermenting polysaccharide into short chain fatty acids (SCFAs). Decreased Turicibacter and increased Lactococcus are consistent with elevated inflammation in the obese status. Differential functional pathways of the gut microbiome in obese rodents included enriched pyruvate metabolism, butanoate metabolism, propanoate metabolism, pentose phosphate pathway, fatty acid biosynthesis, and glycerolipid metabolism pathways. These pathways converge in the function of carbohydrate metabolism, SCFA metabolism, and biosynthesis of lipid. HFD-induced obesity results in structural and functional dysbiosis of gut microbiota. The altered gut microbiome may contribute to obesity development by promoting insulin resistance and systemic inflammation.

A fucoidan from sea cucumber Pearsonothuria graeffei with well-repeated structure alleviates gut microbiota dysbiosis and metabolic syndromes in HFD-fed mice

A high-fat diet (HFD) has been a major contributor to increasing morbidity caused by metabolic syndromes.

Gut microbiome in multiple sclerosis: The players involved and the roles they play

The human gut contains trillions of bacteria (microbiome) that play a major role in maintaining a healthy state for the host. Perturbation of this healthy gut microbiome might be an important environmental factor in the pathogenesis of inflammatory autoimmune diseases such as multiple sclerosis (MS). Others and we have recently reported that MS patients have gut microbial dysbiosis (altered microbiota) with the depletion of some and enrichment of other bacteria. However, the significance of gut bacteria that show lower or higher abundance in MS is unclear. The majority of gut bacteria are associated with certain metabolic pathways, which in turn help in the maintenance of immune homeostasis of the host. Here we discuss recent MS microbiome studies and the possible mechanisms through which gut microbiome might contribute to the pathogenesis of MS.

Bovine milk oligosaccharides decrease gut permeability and improve inflammation and microbial dysbiosis in diet-induced obese mice

Obesity is characterized by altered gut homeostasis, including dysbiosis and increased gut permeability closely linked to the development of metabolic disorders. Milk oligosaccharides are complex sugars that selectively enhance the growth of specific beneficial bacteria in the gastrointestinal tract and could be used as prebiotics. The aim of the study was to demonstrate the effects of bovine milk oligosaccharides (BMO) and Bifidobacterium longum ssp. infantis (B. infantis) on restoring diet-induced obesity intestinal microbiota and barrier function defects in mice. Male C57/BL6 mice were fed a Western diet (WD, 40% fat/kcal) or normal chow (C, 14% fat/kcal) for 7 wk. During the final 2 wk of the study, the diet of a subgroup of WD-fed mice was supplemented with BMO (7% wt/wt). Weekly gavage of B. infantis was performed in all mice starting at wk 3, yet B. infantis could not be detected in any luminal contents when mice were killed. Supplementation of the WD with BMO normalized the cecal and colonic microbiota with increased abundance of Lactobacillus compared with both WD and C mice and restoration of Allobaculum and Ruminococcus levels to that of C mice. The BMO supplementation reduced WD-induced increase in paracellular and transcellular flux in the large intestine as well as mRNA levels of the inflammatory marker tumor necrosis factor α. In conclusion, BMO are promising prebiotics to modulate gut microbiota and intestinal barrier function for enhanced health.

Chronic Repression of mTOR Complex 2 Induces Changes in the Gut Microbiota of Diet-induced Obese Mice

Alterations in the gut microbiota play a crucial role in host physiology and metabolism; however, the molecular pathways underlying these changes in diet-induced obesity are unclear. Mechanistic target of rapamycin (mTOR) signaling pathway is associated with metabolic disorders such as obesity and type 2 diabetes (T2D). Therefore, we examined whether changes in the regulation of mTOR signaling induced by diet (a high-fat diet [HFD] or normal-chow diet) and/or therapeutics (resveratrol [a specific inhibitor of mTOR complex 1] or rapamycin [an inhibitor of both mTOR complex 1 and 2]) altered the composition of the gut microbiota in mice. Oral administration of resveratrol prevented glucose intolerance and fat accumulation in HFD-fed mice, whereas rapamycin significantly impaired glucose tolerance and exacerbated intestinal inflammation. The abundance of Lactococcus, Clostridium XI, Oscillibacter, and Hydrogenoanaerobacterium increased under the HFD condition; however, the abundance of these species declined after resveratrol treatment. Conversely, the abundance of unclassified Marinilabiliaceae and Turicibacter decreased in response to a HFD or rapamycin. Taken together, these results demonstrated that changes in the composition of intestinal microbiota induced by changes in mTOR activity correlate with obese and diabetic phenotypes.

Colonic inflammation accompanies an increase of β-catenin signaling and Lachnospiraceae/Streptococcaceae bacteria in the hind gut of high-fat diet-fed mice

Consumption of an obesigenic/high-fat diet (HFD) is associated with a high colon cancer risk and may alter the gut microbiota. To test the hypothesis that long-term high-fat (HF) feeding accelerates inflammatory process and changes gut microbiome composition, C57BL/6 mice were fed HFD (45% energy) or a low-fat (LF) diet (10% energy) for 36 weeks. At the end of the study, body weights in the HF group were 35% greater than those in the LF group. These changes were associated with dramatic increases in body fat composition, inflammatory cell infiltration, inducible nitric oxide synthase protein concentration and cell proliferation marker (Ki67) in ileum and colon. Similarly, β-catenin expression was increased in colon (but not ileum). Consistent with gut inflammation phenotype, we also found that plasma leptin, interleukin 6 and tumor necrosis factor α concentrations were also elevated in mice fed the HFD, indicative of chronic inflammation. Fecal DNA was extracted and the V1-V3 hypervariable region of the microbial 16S rRNA gene was amplified using primers suitable for 454 pyrosequencing. Compared to the LF group, the HF group had high proportions of bacteria from the family Lachnospiraceae/Streptococcaceae, which is known to be involved in the development of metabolic disorders, diabetes and colon cancer. Taken together, our data demonstrate, for the first time, that long-term HF consumption not only increases inflammatory status but also accompanies an increase of colonic β-catenin signaling and Lachnospiraceae/Streptococcaceae bacteria in the hind gut of C57BL/6 mice.

Heat-killed and live Lactobacillus reuteri GMNL-263 exhibit similar effects on improving metabolic functions in high-fat diet-induced obese rats

Our objective was to investigate and compare the effects of heat-killed (HK) and live Lactobacillus reuteri GMNL-263 (Lr263) on insulin resistance and its related complications in high-fat diet (HFD)-induced rats. Male Sprague-Dawley rats were fed with a HFD with either HK or live Lr263 for 12 weeks. The increases in the weight gain, serum glucose, insulin, and lipid profiles in the serum and liver observed in the HFD group were significantly reduced after HK or live Lr263 administration. Feeding HK or live Lr263 reversed the decreased number of probiotic bacteria and increased the number of pathogenic bacteria induced by high-fat treatment. The decreased intestinal barrier in the HFD group was markedly reversed by HK or live Lr263 treatments. The elevations of pro-inflammatory associated gene expressions in both adipose and hepatic tissues by high-fat administration were markedly decreased by HK or live Lr263 treatments. The increased macrophage infiltration noticed in adipose tissue after high-fat treatment was effectively suppressed by HK or live Lr263 consumption. The insulin resistance associated gene expressions in both adipose and hepatic tissues, which were downregulated in the HFD group, were markedly enhanced after HK or live Lr263 administration. HK or live Lr263 consumption significantly decreased hepatic lipogenic gene expressions stimulated by high-fat treatment. Administration of HK or live Lr263 significantly reduced hepatic oil red O staining and ameliorated the hepatic steatosis observed in high-fat treated rats. Our data suggested that similar to live Lr263, HK Lr263 exerted significant effects on attenuating obesity-induced metabolic abnormalities by reducing insulin resistance and hepatic steatosis formation.

Isolation of lactobacillus reuteri from Peyer's patches and their effects on sIgA production and gut microbiota diversity

SCOPE

We previously reported that specific Lactobacillus reuteri colonized within mouse Peyer's patches (PP) effectively prevented high fat diet induced obesity and low-grade chronic inflammation. We further investigated the role of PP Lactobacillus reuteri on sIgA production in rats in this study.

METHODS AND RESULTS

Lactobacilli were isolated from rat PP. All isolates were L. reuteri and belonged to three phenotypes according to amplified fragment length polymorphism analysis. Typical strains of two main clusters, PP1 and PP2, were used to treat control and vitamin A deficient (VAD) rats, respectively. The feeding of PP1 and PP2 affected sIgA and Lactobacillus diversity by strain-specific manner. Free sIgA was significantly increased by PP1 (p = 0.069) and PP2 (p < 0.05) in the control rats but not in the VAD rats. Only PP1 significantly changed PP Lactobacillus diversity in the control rats (p < 0.05). However, PP2 specifically changed ileal Lactobacillus diversity in both control and VAD rats. Fecal sIgA was correlated with PP Lactobacillus diversity (R(2) = 0.7958, p = 0.011).

CONCLUSION

Modulation of sIgA production by PP L. reuteri of rat is dependent on vitamin A and change of Lactobacillus diversity in PP.

High-fat-diet-induced obesity is associated with decreased antiinflammatory Lactobacillus reuteri sensitive to oxidative stress in mouse Peyer's patches

OBJECTIVE

Diet-induced inflammation in the small intestine may represent an early event that precedes and predisposes to obesity and insulin resistance. This is related to decrease of lactobacilli in Peyer's patches (PP) revealed in our previous study. The present study aimed to clarify specific changes of PP Lactobacillus on the strain level and related biological activity.

METHODS

C57 BL/6 J male mice were fed with either low-fat diet (control [CT]; 10% calories from fat) or high-fat diet (HFD; 50% calories from fat) for 25 wk, and the HFD-fed mice were classified into obesity prone (OP) or obesity resistant (OR) on the basis of their body weight gain. Lactobacillus was isolated from PP using a selective medium. Oxidative resistance and cytokine-inducing effect were analyzed in vitro.

RESULTS

We obtained 52, 18, and 22 isolates from CT, OP, and OR mice, respectively. They belonged to 13 different types according to enterobacterial repetitive intergenic consensus sequence-PCR analysis. Lactobacillus reuteri was the most abundant strain, but its abundance in OP mice was much lower than that in CT and OR mice. This strain includes eight subgroups according to genotyping. L. reuteri L3 and L. reuteri L8 were the specific strains found in CT and OP mice, respectively. Oxidative-resistant L. reuteri was much higher in HFD-fed mice. When co-cultured with PP cells, L8 induced higher production of proinflammatory cytokines such as interleukin (IL)-6, IL-12, and tumor necrosis factor-α, whereas L3 induced higher production of an anti-inflammatory cytokine (IL-10).

CONCLUSION

HFD may induce oxidative stress that drives strain selection of Lactobacillus strains, resulting in decreased anti-inflammatory response in PP.

Rhythmicity of the intestinal microbiota is regulated by gender and the host circadian clock

In mammals, multiple physiological, metabolic, and behavioral processes are subject to circadian rhythms, adapting to changing light in the environment. Here we analyzed circadian rhythms in the fecal microbiota of mice using deep sequencing, and found that the absolute amount of fecal bacteria and the abundance of Bacteroidetes exhibited circadian rhythmicity, which was more pronounced in female mice. Disruption of the host circadian clock by deletion of Bmal1, a gene encoding a core molecular clock component, abolished rhythmicity in the fecal microbiota composition in both genders. Bmal1 deletion also induced alterations in bacterial abundances in feces, with differential effects based on sex. Thus, although host behavior, such as time of feeding, is of recognized importance, here we show that sex interacts with the host circadian clock, and they collectively shape the circadian rhythmicity and composition of the fecal microbiota in mice.