Search Results (41)

Brain tumors (BTs), including glioblastoma (GBM) and meningioma (MGM), contribute significantly to the global cancer burden. The microbiome has been implicated in carcinogenesis, yet its role in BTs remains underexplored. We performed 16S rRNA gene sequencing of the gut microbiota (GM) and intratumoral microbiome (ItM) from fresh tissue samples of 9 patients with GBM and 18 with MGM. 12 age- and sex-matched healthy controls (HCs) were also enrolled. GM profiling revealed reduced alpha diversity and distinct microbial communities in BT patients versus HCs. Notably, Verrucomicrobiota and Synergistaceae were enriched, while Lachnospiraceae, Peptostreptococcaceae, and Muribacter spp. were depleted. GBM patients showed reductions in Peptostreptococcaceae and the Eubacterium hallii group, while MGM patients had increased Synergistia and Erysipelatoclostridium. Compared with MGM, GBM patients were enriched in Peptostreptococcales–Tissierellales, Coprobacillus, and Peptoniphilus but depleted in Weissella. Venn analysis revealed 176 genera shared across groups with unique taxa distinguishing tumor patients and HCs. ItM profiling revealed enrichment of Proteobacteria, Actinomycetota, and Campylobacterota in GBM, while MGM contained higher levels of Bacillota and Bacteroidota. GBM tissues harbored Burkholderia-Caballeronia-Paraburkholderia, Helicobacter, and Leifsonia, whereas MGM tissues were dominated by Bacteroides and Blautia. Notably, stool and tumor samples shared 91 genera in GBM and 105 in MGM. This study provides novel insights by (i) characterizing ItM from fresh samples, (ii) comparing ItM profiles of GBM and MGM, (iii) linking GM and ItM within the same patients, and (iv) suggesting potential clinical implications for BT management. Full article

Background and Aim: Underweight young adult women are vulnerable to health risks such as menstrual disorders and vitamin deficiencies. Because few seek medical care for low body weight, the underlying causes remain unclear. This study aimed to examine the associations of body type with dietary patterns and gut microbiota diversity in young women. Methods: We enrolled 40 women aged 20–39 years who visited a nutrition evaluation clinic with a BMI < 17.5 at their first consultation (underweight group) and 40 age-matched women with 18.5 ≤ BMI < 25 (control group). Some women in the underweight group were no longer underweight at the time of analysis but were classified based on their initial BMI. Dietary patterns were assessed based on ten major food categories (meat, fish, eggs, dairy products, soybeans, green and yellow vegetables, seaweed, fruit, tubers, and fats and oil) based on the Food Frequency Questionnaire based on Food Groups. Gut microbiota α-diversity was evaluated using the Shannon, Simpson, and Pielou indices, while β-diversity was analyzed by nonmetric multidimensional scaling (NMDS) and redundancy analysis (RDA). Genera contributing to group differences were identified by RDA and ANOVA-Like Differential Expression tool (ALDEx2). Results: Underweight women had significantly lower gut microbiota α-diversity, while no difference was observed in dietary patterns. NMDS revealed significant β-diversity differences in gut microbiota (PERMANOVA: R² = 0.064, F = 5.31, p = 0.0001) but not in dietary patterns (p = 0.99). RDA showed that body type explained 4.5% of variance (adjusted R² = 0.032, F = 3.65, p = 0.0005). Bacteroides, Bifidobacterium, Enterocloster, and Erysipelatoclostridium were enriched in underweight women, whereas Fusicatenibacter, Agathobacter, Dorea, and Prevotella were enriched in controls. AldEx2 confirmed increases in Bacteroides, Enterocloster, and Erysipelatoclostridium and a decrease in Dorea. Conclusions: Underweight women demonstrated reduced gut microbiota diversity and enrichment of taxa associated with inflammatory tendencies. Dietary therapies involving not only prebiotics but also probiotics may beneficially modulate gut microbiota and contribute to the management of low body weight. Full article

This study evaluated the protective effects of magnolol, rutin, and gallic acid in broilers fed oxidized soybean oil. Four hundred seven-day-old male Arbor Acre broilers were randomly assigned to five treatments with eight replicates each: CON (4% fresh oil), OOC (4% oxidized oil), and OOC supplemented with 200 mg/kg of magnolol (MAG), rutin (RUT), or gallic acid (GAA). OOC significantly reduced 42-day body weight (BW), average daily gain (ADG), and average daily feed intake (ADFI), reduced serum antioxidant enzyme activities (T-SOD, GSH-Px) and elevated malondialdehyde and triglyceride levels. It also upregulated hepatic lipogenic (FASN, ACACA, SREBP-1) and inflammation (NF-κB1/2) genes, damaged intestinal morphology, reduced cecal Erysipelatoclostridium and Shuttleworthia abundances, and elevated oxidized lipids (9,10-DiHOME and prostaglandin G2) in breast muscle. All three polyphenols increased ADFI (22–42 d), ileal villus height and ZO-1 expression, while reducing serum triglycerides, ileal MDA, and hepatic NF-κB2 expression. Both magnolol and rutin further enhanced BW (42 d) and ADG (7–42 d), decreased ACACA expression, and elevated cecal Lachnoclostridium abundance. Additionally, magnolol significantly decreased the contents of 9,10-DiHOME and malondialdehyde, while rutin reduced prostaglandin G2 levels in the breast muscle. In conclusion, polyphenol supplementation alleviated oxidized oil-induced adverse effects, with magnolol and rutin being more effective. Full article

As an important feed source for ruminants, alfalfa’s rational and efficient utilization is of great significance for the production and economic benefits of pastures. This study focuses on Sanhe dairy cows and includes a control group (CON group, alfalfa in the diet is hay) and an experimental group (AS group, alfalfa silage partially replaces alfalfa hay of equal dry weight). The feeding experiment lasted for 60 days. The results revealed that, compared with the CON group, the AS group exhibited increased milk yield, milk protein, and milk fat. There were no significant differences in apparent digestibility, serum biochemical indicators, and volatile fatty acid (VFA) levels between the two groups. However, the microbial composition of the rumen differed significantly between the two groups of cows based on β-diversity. On the genus level, compared with the CON group, the relative abundance of Erysipelatoclostridium, Pseudoflavonifractor, and Candidatus Saccharimonas in the AS group was significantly reduced. In summary, partially replacing alfalfa hay with alfalfa silage feed is beneficial for improving the production performance of cows and changing rumen microbial diversity. These findings provide a basis for the effective utilization of alfalfa. Full article

Background/Objective: Alcohol consumption has been linked to alterations in gut microbiota and insulin resistance. The alcohol dehydrogenase 1B (ADH1B) gene plays a crucial role in alcohol catabolism, where rs1229984 variant carriers (CT/TT) catabolize ethanol at an 80-fold faster rate than non-carriers (CC). This study investigates the relationships between ADH1B gene rs1229984 mutation, alcohol consumption, gut microbiota, and insulin resistance. Methods: We performed cross-sectional analysis on fecal metagenomic sequencing data from diabetes-free participants in a longitudinal cohort of the Hispanic Community Health Study/Study of Latinos. We used Analysis of Composition of Microbiomes to identify gut microbial species associated with alcohol consumption in non-carriers (n = 1399) and carriers (n = 193). We constructed genotype-specific gut microbiome scores (GMSs) based on the identified species associated with alcohol consumption to examine how gut microbiota may influence the relationship between alcohol consumption and insulin resistance across ADH1B genotypes. Insulin resistance was defined as Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) > 2.5. Results: Distinct microbial species associated with alcohol consumption were identified in non-carriers (54 species) and carriers (16 species). In non-carriers, the genotype-specific GMS modified the relationship between alcohol consumption and insulin resistance (P_interaction = 0.011). The odds ratios (OR) for insulin resistance with increasing alcohol consumption levels across low, moderate, and high tertiles of GMS were 0.75 (95%CI 0.58–0.96), 0.82 (0.67–1), and 1.13 (0.93–1.39), respectively. We identified that individual alcohol-related species, such as Prevotella copri, Ruminococcus callidus, and Erysipelatoclostridium ramosum, modified the relationship between alcohol consumption and insulin resistance in non-carriers. Conclusions: This study suggests that the ADH1B gene rs1229984 mutation is associated with gut microbiota profiles altered by alcohol consumption. Our findings also suggest a potential role of gut microbiota in the protective association between alcohol consumption and insulin resistance in the ADH1B variant non-carriers. Full article

Background: Type 2 diabetes (T2D) is a global health epidemic with rising prevalence within Asian populations, particularly amongst individuals with high visceral adiposity and ectopic organ fat, the so-called Thin-Outside, Fat-Inside phenotype. Metabolomic and microbiome shifts may herald T2D onset, presenting potential biomarkers and mechanistic insight into metabolic dysregulation. However, multi-omics datasets across ethnicities remain limited. Methods: We performed cross-sectional multi-omics analyses on 171 adults (99 Asian Chinese, 72 European Caucasian) from the New Zealand-based TOFI_Asia cohort at 4-years follow-up. Paired plasma and faecal samples were analysed using untargeted metabolomic profiling (polar/lipid fractions) and shotgun metagenomic sequencing, respectively. Sparse multi-block partial least squares regression and discriminant analysis (DIABLO) unveiled signatures associated with ethnicity, glycaemic status, and sex. Results: Ethnicity-based DIABLO modelling achieved a balanced error rate of 0.22, correctly classifying 76.54% of test samples. Polar metabolites had the highest discriminatory power (AUC = 0.96), with trigonelline enriched in European Caucasians and carnitine in Asian Chinese. Lipid profiles highlighted ethnicity-specific signatures: Asian Chinese showed enrichment of polyunsaturated triglycerides (TG.16:0_18:2_22:6, TG.18:1_18:2_22:6) and ether-linked phospholipids, while European Caucasians exhibited higher levels of saturated species (TG.16:0_16:0_14:1, TG.15:0_15:0_17:1). The bacteria Bifidobacterium pseudocatenulatum, Erysipelatoclostridium ramosum, and Enterocloster bolteae characterised Asian Chinese participants, while Oscillibacter sp. and Clostridium innocuum characterised European Caucasians. Cross-omic correlations highlighted negative correlations of Phocaeicola vulgatus with amino acids (r = −0.84 to −0.76), while E. ramosum and C. innocuum positively correlated with long-chain triglycerides (r = 0.55–0.62). Conclusions: Ethnicity drove robust multi-omic differentiation, revealing distinctive metabolic and microbial profiles potentially underlying the differential T2D risk between Asian Chinese and European Caucasians. Full article

Background/Objectives: Nontuberculous mycobacterial pulmonary disease (NTM-PD) is treated using a combination of multiple antimicrobial agents and prolonged therapy; however, recurrence and reinfection rates remain high. Susceptibility to NTM-PD is not fully understood. We aimed to investigate the association between NTM-PD and gut microbiota and determine the impact of antimicrobial therapy on the composition of the gut microbiota. Methods: We analyzed the gut microbiota of 20 Japanese females with NTM-PD (mean age: 67.9 years; range: 50–80 years) at different treatment stages—before, during, and at recurrence—alongside 20 healthy individuals, using 16S rRNA gene amplicon sequencing. Results: Subgroup A (pre-treatment) showed a small difference in β-diversity when compared with the healthy control (HC) group, while no significant differences in α-diversity were observed. Subgroup B (during treatment) exhibited a larger difference in β-diversity compared with the HC group, along with a decrease in α-diversity. The α-diversity of the gut microbiota in Subgroup C (at recurrence) was lower than that in Subgroup A but higher than that in Subgroup B. In Subgroups A and C, the bacterial taxa Sutterella, Adlercreutzia, Odoribacter, and Prevotella had decreased relative abundance, while Erysipelatoclostridium, Massilimicrobiota, Flavonifractor, Eggerthella, and Fusobacterium had increased relative abundance compared to those in the HC group. Conclusions: The loss of normal resident gut bacteria may hinder reacquisition. Treatment may be associated with the persistence of a dysbiotic gut microbiota, fostering susceptibility to NTM-PD. Gut microbiota dysbiosis may heighten susceptibility to NTM-PD, complicate treatment outcomes, and increase the risk of microbiological recurrence following therapy. Full article

Background/Objectives: Inflammatory bowel disease (IBD) is a persistent inflammatory condition affecting the gastrointestinal tract, distinguished by the impairment of the intestinal epithelial barrier, dysregulation of the gut microbiota, and abnormal immune responses. Cajanus cajan (L.) Millsp., traditionally used in Chinese herbal medicine for gastrointestinal issues such as bleeding and dysentery, has garnered attention for its potential therapeutic benefits. However, its effects on IBD remain largely unexplored. Methods: In this study, the major compounds from Cajanus cajan leaf extract (CCLE) were initially characterized by LCMS-IT-TOF. The IBD model was developed in C57BL/6 mice by administering continuous 4% (w/v) dextran sodium sulfate (DSS) aqueous solution over a period of seven days. The body weight, colon length, disease activity index (DAI), and histopathological examination using hematoxylin and eosin (H&E) staining were performed in the IBD model. The levels of the main inflammatory factors, specifically TNF-α, IL-1β, IL-6, and myeloperoxidase (MPO), were quantified by employing enzyme-linked immunosorbent assay (ELISA) kits. Additionally, the levels of tight junction proteins (ZO-1, Occludin) and oxidative stress enzymes (iNOS, SOD1, CAT) were investigated by qPCR. Subsequently, flow cytometry was employed to analyze the populations of various immune cells within the spleen, thereby assessing the impact of the CCLE on the systemic immune homeostasis of IBD mice. Finally, 16S rDNA sequencing was conducted to examine the composition and relative abundance of gut microbiota across different experimental groups. In addition, molecular docking analysis was performed to assess the interaction between the principal components of CCLE and the aryl hydrocarbon receptor (AHR). Results: We identified seven bioactive compounds in CCLE: catechin, cajachalcone, 2-hydroxy-4-methoxy-6-(2-phenylcinyl)-benzoic acid, longistylin A, longistylin C, pinostrobin, amorfrutin A, and cajaninstilbene acid. Our results demonstrated that oral administration of CCLE significantly alleviates gastrointestinal symptoms in DSS-induced IBD mice by modulating the balance of gut-derived pro- and anti-inflammatory cytokines. This modulation is associated with a functional correction in M1/M2 macrophage polarization and the Th17/Treg cell balance in splenic immune cells, as well as shifts in the populations of harmful bacteria (Erysipelatoclostridium and Staphylococcus) and beneficial bacteria (Odoribacter, unidentified Oscillospiraceae, Lachnoclostridium, and Oscillibacter) in the gut. Furthermore, cajaninstilbene acid, longistylin A, and longistylin C were identified as potential AhR agonists. Conclusions: The present results suggested that CCLE, comprising stilbenes like cajaninstilbene acid, longistylin A, and longistylin C, protects the epithelial barrier’s structure and function against DSS-induced acute IBD by restoring gut microbiota balance and systemic immune response as AhR agonists. Overall, CCLE represents a promising natural product-based therapeutic strategy for treating IBD by restoring gut microbiota balance and modulating systemic immune responses. Full article

This study investigated whether variations in growth response to low nutrient density across breeds are linked to microbiota regulation. Arbor Acres (AA) and Beijing-You (BY) were fed high- (HN) and low-nutrient (LN) diets from day (d) 0 to d42. Body weight, feed intake, and intestinal measurements were recorded, and microbiota from the ileum and cecum were analyzed on d7, d21, and d42. Results showed that AA broilers had greater growth performance with a lower feed conversion ratio (FCR) and greater average daily gain (ADG) than BY chickens. The LN diet negatively affected AA broiler growth due to impaired intestinal development, while BY chickens compensated by increasing feed intake. Microbiota composition was primarily affected by breed than by nutrient density, with AA broilers having more beneficial bacteria and BY chickens having more short-chain fatty acid (SCFA)-producing bacteria. The LN diets reduced anti-inflammatory bacteria such as Shuttleworthia and Eisenbergiella in the cecum on d7. By d21, LN diets decreased Lactobacillus and increased proinflammatory Marvinbryantia, potentially impairing growth. However, LN diets enriched SCFA-producing bacteria like Ruminococcaceae_UCG.013, Eisenbergiella, and Tyzzerella in BY chickens and Faecalitalea in AA broilers by d21, which may benefit gut health. By d42, LN diets reduced genera linked to intestinal permeability and fat deposition, including Ruminococcus_torques_group, Romboutsia, Erysipelatoclostridium, and Oscillibacter. Additionally, LN diets enriched Christensenellaceae_R-7_group in AA broilers, associated with intestinal barrier integrity, and increased anti-inflammatory bacteria Alistipes and Barnesiella in AA broilers and BY chickens, respectively, by d42. Overall, AA broilers were more susceptible to reduced nutrient density due to impaired intestinal development, while BY chickens adapted better by increasing feed intake. The microbiota responses to low nutrient density varied over time, potentially negatively affecting gut health in the early stage and growth in the middle stage but possibly improving lipid deposition and gut health in the middle and late stages. Full article

Avian coccidiosis, caused by several species of Eimeria, is a widespread and economically important poultry disease that inflicts severe losses in the poultry industry. Understanding the interplay between Eimeria and gut microbiota is critical for controlling coccidiosis and developing innovative treatments to ensure good poultry health. In the present study, chickens were immunized six times with a low dose of Eimeria tenella, resulting in complete immunity against Eimeria infection. The results of fecal microbiota transplantation showed that the gut microbiota of immunized chickens induced a certain degree of resistance to coccidial infection. To investigate the types of intestinal microbiota involved in the development of resistance to Eimeria, the intestinal contents and fecal samples from both immunized and unimmunized groups were collected for 16S rRNA gene sequencing. The results showed that, at the genus level, the abundance of the Eubacterium coprostanoligenes group, Erysipelatoclostridium, Shuttleworthia, and Colidextribacter was significantly increased in the intestinal content of immunized chickens, whereas the abundance of Eisenbergiella was significantly decreased. In fecal samples, the abundance of Clostridiaceae and Muribaculaceae significantly increased, whereas that of Bacillales significantly decreased. These findings will help to elucidate the interactions between E. tenella and the gut microbiota of chickens, providing a basis for isolating E. tenella-resistant strains from the gut microbiome and developing new vaccines against coccidiosis. Full article

The experiment investigated the effects of sea-buckthorn flavonoids (SF) on lipopolysaccharide (LPS)-challenged broilers. A total of 288 one-day-old male broilers were randomly assigned to 4 groups, with 6 replicates of 12 broilers each. The experiment lasted for 20 days. The diet included two levels of SF (0 or 1000 mg/kg) and broilers intraperitoneally injected with 500 μg/kg LPS on 16, 18, and 20 days, or an equal amount of saline. LPS challenge decreased final body weight, average daily gain, and average daily feed intake, increased feed-to-gain ratio, and elevated serum IL-1β, IL-2, TNF-α, D-LA, and endotoxin levels. Moreover, it resulted in a reduction in the IL-10 level. LPS impaired the intestinal morphology of the duodenum, jejunum, and ileum, down-regulated the mRNA relative expression of Occludin, ZO-1, and MUC-2 in the jejunum mucosa, up-regulated the mRNA relative expression of TLR4, MyD88, NF-κB, and IL-1β, and increased the relative abundance of Erysipelatoclostridium in broilers (p < 0.05). However, SF supplementation mitigated the decrease in growth performance, reduced serum IL-1β, IL-2, and D-LA levels, increased IL-10 levels, alleviated intestinal morphological damage, up-regulated mRNA expression of Occludin and ZO-1, down-regulated the mRNA expression of TLR4, NF-κB, and IL-lβ in jejunum mucosal (p < 0.05), and SF supplementation presented a tendency to decrease the relative abundance of proteobacteria (0.05 < p < 0.1). Collectively, incorporating SF can enhance the growth performance, alleviate serum inflammation, and improve the intestinal health of broilers, effectively mitigating the damage triggered by LPS-challenges. Full article

Lactarius hatsudake (LH), a great wild endemic fungus, contains rich nutritional components with medicinal properties. The effects of LH on body weight, liver weight, liver injury, blood lipids, and gut microbiota in C57BL/6 mice fed a high-fat diet (HFD) for 8 weeks was examined in this research. Though there was no clear impact on weight loss, the findings indicate that LH treatment effectively decreased liver damage caused by HFD, as well as lowered serum total cholesterol, triacylglycerol, and low-density lipoprotein cholesterol levels. Additionally, it positively influenced gut microbiota to resemble that of mice on a normal diet. In HFD-fed mice, LH markedly boosted the levels of Parabacteroides, unclassified Muribaculaceae, Oscillibacter, and unclassified Oscillospiraceae, while reducing the abundance of Lachnospiraceae NK4A136 group and Erysipelatoclostridium, as well as the ratio of Firmicutes to Bacteroidetes. Further analysis of correlation indicate a possible connection between obesity and gut microbiota. Obesity-related indices show a positive association with unclassified Eubacterium coprostanoligenes group, Blautia, and Erysipelatoclostridium, while displaying a negative correlation with unclassified Muribaculaceae, unclassified Clostridia vadinBB60 group, Helicobacter, Oscillibacter, unclassified Ruminococcaceae, Parabacteroides, and unclassified Oscillospiraceae. The results suggest that LH can help combat obesity and may have the potential to be utilized as a functional food. Full article

Gut dysbiosis and subclinical intestinal damage are common in cirrhosis. The aim of this study was to examine the association of intestinal damage biomarkers (diamine oxidase [DAO], claudin 3, and intestinal fatty acid binding protein [I-FABP; FABP2]) with the state of the gut microbiota in cirrhosis. The blood levels of DAO were inversely correlated with blood levels of claudin 3, lipopolysaccharide (LPS), presepsin, TNF-α, and the severity of cirrhosis according to Child–Pugh scores. The blood level of I-FABP was directly correlated with the blood level of claudin 3 but not with that of DAO. Patients with small intestinal bacterial overgrowth (SIBO) had lower DAO levels than patients without SIBO. There was no significant difference in claudin 3 levels and I-FABP detection rates between patients with and without SIBO. The DAO level was directly correlated with the abundance of Akkermansiaceae, Akkermansia, Allisonella, Clostridiaceae, Dialister, Lactobacillus, Muribaculaceae, Negativibacillus, Ruminococcus, Thiomicrospiraceae, Verrucomicrobiae, and Verrucomicrobiota; and it was inversely correlated with the abundance of Anaerostipes, Erysipelatoclostridium, and Vibrio. The I-FABP level was directly correlated with Anaerostipes, Bacteroidia, Bacteroidota, Bilophila, Megamonas, and Selenomonadaceae; and it was inversely correlated with the abundance of Brucella, Pseudomonadaceae, Pseudomonas, and Vibrionaceae. The claudin 3 level was directly correlated with Anaerostipes abundance and was inversely correlated with the abundance of Brucella, Coriobacteriia, Eggerthellaceae, and Lactobacillus. Full article

Our aim was to study the association of endothelial dysfunction biomarkers with cirrhosis manifestations, bacterial translocation, and gut microbiota taxa. The fecal microbiome was assessed using 16S rRNA gene sequencing. Plasma levels of nitrite, big endothelin-1, asymmetric dimethylarginine (ADMA), presepsin, and claudin were measured as biomarkers of endothelial dysfunction, bacterial translocation, and intestinal barrier dysfunction. An echocardiography with simultaneous determination of blood pressure and heart rate was performed to evaluate hemodynamic parameters. Presepsin, claudin 3, nitrite, and ADMA levels were higher in cirrhosis patients than in controls. Elevated nitrite levels were associated with high levels of presepsin and claudin 3, the development of hemodynamic circulation, hypoalbuminemia, grade 2–3 ascites, overt hepatic encephalopathy, high mean pulmonary artery pressure, increased abundance of Proteobacteria and Erysipelatoclostridium, and decreased abundance of Oscillospiraceae, Subdoligranulum, Rikenellaceae, Acidaminococcaceae, Christensenellaceae, and Anaerovoracaceae. Elevated ADMA levels were associated with higher Child–Pugh scores, lower serum sodium levels, hypoalbuminemia, grade 2–3 ascites, milder esophageal varices, overt hepatic encephalopathy, lower mean pulmonary artery pressure, and low abundance of Erysipelotrichia and Erysipelatoclostridiaceae. High big endothelin-1 levels were associated with high levels of presepsin and sodium, low levels of fibrinogen and cholesterol, hypocoagulation, increased Bilophila and Coprobacillus abundances, and decreased Alloprevotella abundance. Full article

Intestinal bacteria, synchronized with diet and feeding time, exhibit circadian rhythms and anticipate host gut function; however the effect of dietary probiotics on gut bacterial diurnal rhythms remains obscure. In this study, bacteria were sequenced at 6 Zeitgeber times (ZT) from a pig model of ileal T-shaped fistula to test ileal bacterial composition and circadian rhythms after Lactobacillus delbrueckii administration. The results showed that dietary L. delbrueckii enhanced ileal bacterial α-diversity at Zeitgeber time (ZT) 16, evidenced by an increased Simpson index compared with control pigs. At the phylum level, Firmicutes was identified as the largest phyla represented in pigs, but dietary L. delbrueckii only increased the abundance of Tenericutes at ZT16. At the genus level, 11/100 genera (i.e., Lactobacillus, Enterococcus, Leptotrichia, Pediococcus, Bifidobacte, Cellulosilyticum, Desulfomicrobium, Sharpea, Eubacterium, Propionivibrio, and Aerococcus) were markedly differentiated in L. delbrueckii-fed pigs and the effect was rhythmicity-dependent. Meanwhile, dietary L. delbrueckii affected six pathways of bacterial functions, such as membrane transport, metabolism of cofactors and vitamins, cell motility, the endocrine system, signaling molecules and interaction, and the nervous system. Cosinor analysis was conducted to test bacterial circadian rhythm in pigs, while no significant circadian rhythm in bacterial α-diversity and phyla composition was observed. Lactobacillus, Terrisporobacter, and Weissella exhibited significant rhythmic fluctuation in the control pigs, which was disturbed by probiotic exposure. In addition, dietary L. delbrueckii affected circadian rhythms in ileal Romboutsia, Erysipelatoclostridium, Cellulosilyticum, and Eubacterium abundances. Dietary L. delbrueckii affected both ileal bacterial composition and circadian rhythms, which might further regulate gut function and host metabolism in pigs. Full article