Sequence and cultivation study of Muribaculaceae reveals novel species, host preference, and functional potential of this yet undescribed family

Investigation of the mechanisms of liver injury induced by emamectin benzoate exposure at environmental concentrations in zebrafish: A multi-omics approach to explore the role of the gut-liver axis

Emamectin benzoate (EMB) is a lipophilic pesticide that enters aquatic systems and adversely affects non-target organisms. This study investigated the long-term effects of EMB on zebrafish, exposing them to concentrations of 0, 0.1, 1, and 10 μg/L from the 4-hour post-fertilization (hpf) embryo stage to the 120-day post-fertilisation (dpf) adult stage. We found that exposure to 1 μg/L EMB induced liver damage, manifested as impaired liver function (elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT)), histopathological damage (lipid accumulation), as well as inflammatory and oxidative damage, with a dose - dependent effect. Non-targeted metabolomic analysis revealed an increase in lipid molecules in the liver, affecting the pathways related to glycerophospholipid metabolism. In addition, EMB exposure resulted in damage to the intestinal barrier and inflammatory responses in zebrafish. 16S rRNA sequencing demonstrated that EMB exposure resulted in notable alterations in the gut microbiota composition. Notably, the abundance of Plesiomonas and Cetobacterium increased in the EMB exposure group and exhibited a positive correlation with the majority of liver lipid metabolites. In contrast, reductions in Muribaculaceae and Alloprevotella were negatively correlated. The results of this study indicate that long-term exposure to EMB disrupts the gut microbiota, leading to the dysregulation of hepatic phospholipid metabolism. These findings provide new insights into the health risks associated with EMB and highlight its potential threats to higher organisms, including mammals.

Inflammation-targeted delivery of probiotics for alleviation of colitis and associated cognitive disorders through improved vitality and colonization

Oral probiotic biotherapies hold significant promise for addressing intestinal inflammatory disorders. Nonetheless, due to the challenging pathological microenvironment of the gastrointestinal tract, it is difficult to achieve deliver probiotics in an inflammation-targeted manner while improving their intestinal colonization and minimizing the impact of gastrointestinal environment on their vitality. To address this, an innovative probiotics oral delivery system (EcN-Apt@HG) against ulcerative colitis (UC) was developed by conjugating IL-6 aptamer to the surface of EcN and subsequently encapsulating the probiotics in a hydrogel consisting of aldehyde-functionalized chondroitin sulfate (CS) and Poly(amidoamine) (PAMAM). As expected, the encapsulated EcN demonstrated resistance to gastrointestinal conditions, and the colonization duration of probiotics in the colon was enhanced via the preferential adhesion effect of IL-6 aptamer on the inflammatory site. The EcN-Apt@HG system restored the damaged mucosal layer, suppressed hyperactive immune responses, and reshaped the dysbiosis of intestinal microflora, thereby synergistically alleviating dextran sulfate sodium (DSS)-induced colitis. Notably, EcN-Apt@HG significantly alleviated depression-like behaviors and cognitive impairment in colitis mice through gut-brain axis interaction. This approach provides a simple and promising strategy for inflammation-targeted delivery of probiotics to the intestine and shows great potential for UC therapy and associated cognitive disorders.

Diet alters the effects of lipopolysaccharide on intestinal health and cecal microbiota composition in C57Bl/6 male mice

Lipopolysaccharide (LPS), a component of the gram-negative bacteria cell well, is established to induce an acute and transient inflammatory cascade upon exogenous administration in mice, while negatively impacting aspects of the microbiota gut-brain axis (mGBA). Dietary supplementation with flaxseed (FS) has been shown to partially attenuate these impairments across the mGBA, although the importance of intestinal and hepatic health has not been established in this context. In this study, we furthered our investigation of the impact of dietary supplementation with FS and FS oil (FO) in mitigating LPS-induced perturbations to intestinal health (i.e. cecal microbiota, barrier integrity, inflammation, short-chain fatty acid (SCFA) production), hepatic inflammation, and their relationships to LPS-induced systemic and neuroinflammation. We noted distinct, diet-dependent shifts in the microbiota composition twenty-four hours post-LPS injection, that may be partially driven by the LPS-induced anorexia. BD-fed mice challenged with LPS showed reduced Muribaculaceae, while FS-LPS mice had elevated Akkermansia, and both the FS-LPS and FO-LPS mice had reduced Bacteroides, each with unique correlations to diet intake. These LPS-driven shifts in the microbiota were coupled with elevated ileal mucous content in the FS- and FO-fed mice, and intestinal inflammation which was partially attenuated in the FS-fed mice. Collectively, we highlight that FS modulates aspects of the intestinal microenvironment, which may be related to the anti-inflammatory effects across the mGBA.

Component specific responses of the microbiomes to common chemical stressors in the human food chain

Along a food chain, microbiomes occur in each component and often contribute to the functioning or the health of their host or environment. 'One Health' emphasizes the connectivity of each component's health. Chemical stress typically causes dysbiotic microbiomes, but it remains unclear whether chemical stressors consistently affect the microbiomes of food chain components. Here, we challenged food chain components, including water, sediments, soil, plants, and animals, with three chemical stresses consisting of arsenic (toxic trace element), benzoxazinoids (bioactive plant metabolites), and terbuthylazine (herbicide). We analysed 1064 microbiomes to assess their commonalities and differences in their stress responses. We found that chemical stressors overall decreased microbiome diversity in soil, but not in the other microbiomes. In response to stress, all food chain communities strongly shifted in their composition, generally becoming compositionally more similar to each other. In addition, we observed stochastic effects in host-associated communities (plant, animal). Dysbiotic microbiomes were characterized by different sets of bacteria, which responded specifically to the three chemical stressors. Microbial co-occurrence patterns significantly shifted with either decreased (water, sediment, plant, animal) or increased (soil) network sparsity and numbers of keystone taxa following stress treatments. These results suggest major re-distribution of specific taxa in the overall stress- and component-specific responses of microbiomes with the community stability of plant and animal microbiomes being the most affected by chemical stresses.

KaiXinSan-JiaWei ameliorates cognitive dysfunction in APP/PS1 mice by intervening in gut microbiota and its metabolites

Background

Alzheimer's disease (AD) is a degenerative disease of the central nervous system characterized by progressive cognitive impairment and memory loss. Chinese medicine's therapeutic effect on AD has become a promising treatment option in recent years, and the Chinese herbal compound Kai Xin San-Jia Wei (KXSJW) is one of its representatives. This study employed a comprehensive approach, including 16S rRNA and Gaschromatography-mass spectrometry (GC-MS) analysis, to investigate the therapeutic efficacy and intrinsic mechanism of KXSJW on AD.

Methods

50 3-month-old APPswe/PS1dE9 transgenic mice were randomly divided into 5 groups (n = 10): model group (M), donepezil group (Don), KXSJW-low dose group (KJW-L), KXSJW- medium dose group (KJW-M), KXSJW-high dose group (KJW-H), Ten 3-month-old C57BL/6 J wild-type mice were randomly selected as the control group (C). The control and model groups were administered saline by gavage, the donepezil group was administered donepezil (0.92 mg/kg/d), and the KXSJW-low/medium/high dose group was administered KXSJW extract (0.9/1.8/3.6 mL/kg/d); each group was treated once daily for 2 months. The study employed the Morris Water Maze (MWM) to evaluate learning and cognitive abilities. Pathological changes in colon tissue were assessed through hematoxylin and eosin (HE) staining. Analysis of gut microbiota was conducted using 16S rRNA sequencing, and gut microbial metabolite (short chain fatty acids, SCFAs) content was detected using GC-MS. Colonic tissue barrier integrity was examined through immunohistochemistry and western blot, while β-amyloid deposition in brain tissue was assessed. ELISA was used to measure serum intestinal peptide hormones (Glucagon, GHRP-Ghrelin).

Results

KXSJW enhanced learning ability and memory, reduced amyloid deposition in the brain tissue of AD model mice. KXSJW was able to restore the balance of intestinal flora and regulate the concentration of intestinal flora metabolites, especially represented by Firmicutes and its major metabolite butyric acid. Meanwhile, KXSJW restored the intestinal barrier function and improved the release level of intestinal peptide hormones (Glucagon, GHRP-Ghrelin) in AD model mice. This indicates that KXSJW can improve the intestinal internal environment of AD model mice.

Conclusion

KXSJW may improve the homeostasis of the gut environment in AD, with a focus on the regulation of gut microorganisms and their metabolites, and subsequently improve cognitive impairment in AD. Traditional Chinese Medicine (TCM) has the potential to intervene in AD through multilevel interaction with the brain-gut-axis.

Comparative analysis of gut microbiota in free range and house fed yaks from Linzhou County

Gut microbiota variations in response to environmental and nutritional factors are of great significance as gut microbiota plays an integral role in nutrient metabolism, immunity, health, and disease conditions. In this context, limited studies investigated variations of gut microbiota in response to different feeding systems and environmental conditions. The current study obtained fresh fecal samples from house-fed (LS) and grazing yaks (LF) from Linzhou County. 16 S rRNA amplicon sequencing of the V3-V4 and internal transcribed spacer 2 (ITS2) domains generated 16,332 bacterial and 2345 fungus amplicon sequence variants (ASVs). Alpha and beta diversity indices revealed significant variations (p > 0.05) in gut microflora between the two groups. At the phylum level, Firmicutes, Actinobacteriota, Bacteroidota, and Patescibacteria regarding bacteria, and Ascomycota and Basidiomycota regarding fungi dominated. At the genus level, UCG-005, Rikenellaceae_RC9_gut_group, Clostridium_sensu_stricto_1, g__Muribaculaceae, UCG-010, [Eubacterium]_coprostanoligenes_group, Turicibacter, Alistipes, Prevotellaceae_UCG-003, UCG-009, Blautia, dgA-11_gut_group, Candidatus_Saccharimonas dominated in LS, while Anthrobacter and Terrisporobacter dominated in the LF group. Fungal genera like Myrothecium and Plectosphaerella dominated the LS group, while Neoascochyta, Paraphaeosphaeria, and Hypocreales dominated the LF group. Also, significant variations (p > 0.05) in gene expressions were found between the two groups. These findings provide insights into yak gut microbiota adaptations and metabolic changes in response to varied environmental conditions and can provide valuable information, optimizing feeding strategies after identifying specific differences between grazing and house-fed yaks, reducing environmental impacts, and improving yaks' health and productivity in specific geographical settings.

Assessing the relationship between the gut microbiota and growth traits in Chinese indigenous pig breeds

BACKGROUND

Gut microbiota plays crucial roles in host metabolism, diseases and development. It has also been reported to be associated with growth performance in pigs. However, the bacterial species influencing pig growth performance have not been isolated, and the mechanisms remain unclear.

RESULTS

In this study, we collected 500 gut microbial samples from two Chinese indigenous pig breeds, including 244 fecal samples from Bamaxiang (BMX) pigs and 256 cecum content samples from Erhualian (EHL) pigs, to investigate the relationship between gut microbiota and pig growth traits. Bacterial compositions were determined by 16 S rRNA gene sequencing, and association analysis was performed using a two-part model. We found that the Firmicutes-to-Bacteroidota ratio in fecal samples from BMX pigs was negatively associated with average daily gain (P = 0.0085). Amplicon sequence variants (ASVs) belonging to Prevotella and three ASVs annotated to Oscillospiraceae were negatively associated with pig growth traits, while ASVs annotated to Muribaculaceae and Rikenellaceae showed positive correlations with growth traits in BMX fecal samples. In cecum content samples from EHL pigs, ASVs belonging to Prevotella, Lactobacillus delbrueckii, and Lachnospiraceae were negatively associated with growth performance, whereas one ASV belonging to Rikenellaceae demonstrated a positive association. Predicted functional capacity analysis revealed that metabolic pathways related to the digestive system, glycan biosynthesis and metabolism, signaling molecules and interactions, and xenobiotics biodegradation and metabolism were positively associated with pig growth traits. Conversely, the excretory system pathway showed a negative correlation. These pathways were found to correlate with growth trait-associated bacterial ASVs, suggesting that alterations in gut bacterial composition led to functional capacity shifts in the gut microbiome, subsequently affecting porcine growth.

CONCLUSIONS

Our results gave significant insights about the effect of gut microbiota on pig growth and provided important evidence to support further isolation of bacterial taxa that influence pig growth for elucidating their mechanisms.

Acid-resistant chemotactic DNA micromotors for probiotic delivery in inflammatory bowel disease

Microcapsules composed of synthetic polymeric matrices have attracted considerable attention in delivering oral probiotics. However, existing polymeric microcapsules demonstrate inadequate acid resistance and adaptability, as well as deficiency in the inflamed colon-specificity and uncontrolled release of probiotics therein. Herein, a DNA microcapsule is prepared as a probiotic-transporting micromotor through photo-crosslinking of hyaluronic acid methacrylate and acrydite-modified A-/C-rich oligomers within the microfludically generated droplets in the presence of nitric oxide-cleavable crosslinker and gas donor manganese carbonyl (MnCO). As the microcapsules traverse stomach, duodenum, and ultimately colon, the formation and dissociation of A-motif and i-motif structures instigate a reversible shrinking-swelling transition of microcapsules to preserve probiotic viability. Subsequently, the microcapsules exhibit chemotaxis towards inflamed colon site, driven by a gas-generating reaction between MnCO and elevated reactive oxygen species. Following disintegration of the microcapsules, triggered by endogenous nitric oxide, probiotics are released to reshape the dysbiosis of intestinal microflora. This advanced delivery system offers significant promise for the effective clinical management of inflammatory bowel disease.

Tea residue protein-derived oligopeptides attenuate DSS-induced acute colitis complicated with hepatic injury in C57BL/6J mice by regulating the gut-microbiome-liver axis

BACKGROUND

Impairment of the intestinal mucosal barrier is a prevalent feature of acute colitis, and untreated acute colitis can lead to extra-intestinal manifestations, including hepatic injury. Previous research has demonstrated that large-leaf yellow tea residue protein-derived oligopeptides (TPP) can alleviate ulcerative colitis symptoms and hepatic injury in mice. However, the underlying regulatory mechanisms by which TPP improves colitis complicated with liver injury are unknown.

PURPOSE

To explore the potential mechanism by which TPP alleviates acute colitis complicated with hepatic injury.

METHODS

Acute colitis with hepatic injury was induced in mice using 3.5 % dextran sodium sulfate. Both 16S rRNA sequencing and transcriptomic analyses were utilized to investigate the impact of TPP on mitigating symptoms in mice.

RESULTS

It indicated that TPP administration effectively reduced inflammatory symptoms in the colon and liver, enhanced the secretion of mucin occluding, claudin-1, ZO-1, and MUC-2, decreased intestinal mucosal permeability, and restored homeostasis within the gut microbiome of mice. Moreover, transcriptomic analysis has evidenced the effectiveness of TPP in mitigating liver-related effects. RNA-seq KEGG enrichment and RT-qPCR analyses validated TPP could modulate the "gut-microbiome-liver" axis, and participate in signaling pathways related to inflammatory regulation, as well as bile acid metabolism and synthesis.

CONCLUSION

These findings suggest that TPP administration is a promising novel approach for preventing and treating acute colitis complicated with hepatic injury.

Wild house mice have a more dynamic and aerotolerant gut microbiota than laboratory mice

The mammalian gut microbiota is a complex microbial community with diverse impacts on host biology. House mice (Mus musculus) are the major model organism for research on mammals, but laboratory domestication has altered their gut microbiota from that of their wild counterparts. Knowledge about how and why the gut microbiota of this species varies between lab and wild settings and among natural populations could improve its utility as a model organism. Here, we use a large dataset comprising over 800 house mouse samples from multiple laboratory facilities and strains and wild mice from mainland and island populations to investigate gut microbiota variation in this species across contrasting genetic and environmental settings. Across geographically disparate populations, we find that wild mice possess a gut microbiota that is compositionally distinct, displays a higher relative abundance and richness of aerotolerant taxa, and is taxonomically and functionally more diverse than that of lab mice. Longitudinally sampled wild mice also display markedly higher temporal turnover in microbiota composition than lab mice. Wild mice from oceanic islands harboured microbiotas that differed subtly from those of mainland wild mice and were more divergent from lab mouse microbiotas. These findings highlight much greater spatial and temporal turnover of gut microbes in wild compared to laboratory mice.

Comparative analyses of the gut microbiome of two sympatric rodent species, Myodes rufocanus and Apodemus peninsulae, in northeast China based on metagenome sequencing

The gut microbiota is integral to an animal's physiology, influencing nutritional metabolism, immune function, and environmental adaptation. Despite the significance of gut microbiota in wild rodents, the Korean field mouse (Apodemus peninsulae) and the gray red-backed vole (Myodes rufocanus) remain understudied. To address this, a metagenomic sequencing analysis of the gut microbiome of these sympatric rodents in northeast China's temperate forests was conducted. Intestinal contents were collected from A. peninsulae and M. rufocanus within the Mudanfeng National Nature Reserve. High-throughput sequencing elucidated the gut microbiome's composition, diversity, and functional pathways. Firmicutes, Bacteroidetes, and Proteobacteria were identified as the dominant phyla, with M. rufocanus showing greater microbiome diversity. Key findings indicated distinct gut bacterial communities between the species, with M. rufocanus having a higher abundance of Proteobacteria. The gut microbiota of A. peninsulae and M. rufocanus differed marginally in functional profiles, specifically in the breakdown of complex carbohydrates, which might reflect their distinct food preferences albeit both being herbivores with a substantial dietary overlap. The investigation further elucidated gut microbiota's contributions to energy metabolism and environmental adaptation mechanisms. This study aligns with information on rodent gut microbiota in literature and highlights the two understudied rodent species, providing comparative data for future studies investigating the role of gut microbiota in wildlife health and ecosystem functioning.

Integrating transcriptomics and Microbiomics to unravel the regulatory effects of Anji white tea on lipid metabolism in HFD-induced obese mice

Obesity has become a significant global health concern. Green tea is widely consumed as an internationally popular beverage and it is recognized that various green teas have unique biological activities. Here, the effects of Anji white tea (a green tea) ‌on lipid metabolism in high-fat-diet (HFD)-fed mice were investigated based on multi-omics. The results showed the functional components and antioxidant activity changed significantly in the whole process (fresh leaves-withering-stripping-drying). Oral gavage of Anji white tea water extract (AJT) for 9 weeks significantly lowered body weight, improved dysglycemia, and alleviated liver oxidative injury. Liver transcriptome analysis revealed that AJT regulated the gene expression related to the "valine, leucine, and isoleucine degradation" pathway, including HADH, HMGCL, ACSF3, ACADS, ALDH3A2, and ACAA2. This result was further validated by qPCR and Western blotting. 16S rRNA sequence analysis showed that AJT improved HFD-induced gut dysbiosis by significantly increasing beneficial genera (e.g., Muribaculaceae_norank and Alloprevotella) and reducing harmful bacteria (e.g., Bacteroides, Lachnospiraceae_uncultured, and Helicobacter). Furthermore, correlation analysis found that AJT-induced alteration of genera was greatly associated with obesity-related parameters and genes involved in the "valine, leucine, and isoleucine degradation" pathway. Collectively, our findings indicated that AJT may alleviate obesity by modulating gut microbiota and the "amino acids, valine, and leucine metabolism" pathway.

Inference of functional differentiation of intestinal microbes between two wild zokor species based on metagenomics

BACKGROUND

Currently, there are fewer studies on the intestinal microbes of wild zokors, and it is unclear how zokors adapt to special underground environments by regulating their intestinal microbes. Here, we explored the function of intestinal microbes of Eospalax cansus and Eospalax rothschildi based on metagenomics.

RESULTS

Both zokor species have similar intestinal microbial composition, but E. cansus has a higher proportion of bacteria involved in carbohydrate degradation. Functional analysis based on KEGG and CAZy databases indicated that the intestinal microbes of E. cansus harboured stronger carbohydrate degradation ability, mainly in starch and sucrose metabolism, and further in cellulose degradation. Furthermore, the cellulase activity was significantly higher in E. cansus than that in E. rothschildi. Eospalax cansus has a stronger microbial fermentation ability due to an increase in fibre-degrading bacteria like unclassified_f_Lachnospiraceae, Ruminococcus, and Clostridium. In addition, the dominant bacteria isolated from zokor were Bacillus, some of which could degrade both cellulose and hemicellulose.

CONCLUSION

Metagenomic analysis and bacterial isolation experiments indicate that E. cansus has a stronger microbial cellulose-degrading capacity, possibly as an adaptation to its limited food resources underground. © 2024 Society of Chemical Industry.

Green tea fermented by Ganoderma lucidum presented anti-obesity properties via enhanced thermogenesis in vitro and on C57BL/6J mice

High-fat diets contribute to obesity and metabolic disorders. Ganoderma lucidum is renowned for its abundant bioactive compounds and diverse pharmacological effects. Green tea fermented by G. lucidum (TFG) has been shown to enhance lipid-lowering activity in vitro significantly. Using UPLC-MS/MS and GC-MS/MS, we identified 78 active lipid-lowering compounds in TFG. We explored their potential targets and pathways through network pharmacology, validated by in vivo experiments. In a 4-week trial, 70 mice were randomly assigned to 7 groups: ND (normal diet), HFD (high-fat diet), PC-HFD (HFD with orlistat), NFT1 (HFD with 200 mg/kg/day non-fermented tea), NFT2 (HFD with 400 mg/kg/day NFT), TFG1 (HFD with 200 mg/kg/day TFG), and TFG2 (HFD with 400 mg/kg/day TFG). TFG treatment significantly reduced body weight, hepatic lipid droplets, and epididymal adipocyte size in mice compared to the HFD group. TFG also increased the abundance of lipid-lowering bacteria, such as Lactococcus and Lachnospirales. Liver transcriptomic and fecal metabolomic analyses revealed that TFG reduced triglyceride (TG), diglyceride (DG), monoglyceride (MG), and free fatty acid (FFA) levels and differentially regulated key genes (Dpf3, Atp5k, ND3) involved in the thermogenesis pathway. RT-PCR confirmed that TFG upregulated the mRNA expressions of AMPK, UCP1, PGC1α, and PPARγ in dorsal fat. In conclusion, TFG enhances thermogenesis via the AMPK-PGC1α pathway and increases the abundance of lipid-lowering bacteria, thereby reducing fat accumulation in mice. These findings offer insights into TFG's anti-obesity mechanisms, providing a scientific basis for developing new weight loss methods or products.

High-viscosity dietary fibers modulate gut microbiota and liver metabolism to prevent obesity in high-fat diet-fed mice

Obesity and metabolic disorders are rising global health concerns, emphasizing the need for effective dietary interventions. High-viscosity dietary fibers such as bacterial cellulose (BC) and guar gum (GG) have unique properties that may complement each other in modulating gut microbiota and metabolic health. This study investigates their effects in high-fat diet-fed mice. BC and GG increase Bacteroides, which degrade polysaccharides and produce short-chain fatty acids (SCFAs), supporting metabolic health. BC enhances bile acid excretion and enriches Faecalibaculum, Duncaniella, and Paramuribaculum, promoting gut barrier integrity and reducing inflammation, potentially improving bile acid turnover and lipid metabolism. GG more effectively increases butyrate production by enhancing butyrate-producing bacteria, such as Clostridium XIVa and Kineothrix, and promotes Bifidobacterium, strengthening anti-inflammatory effects and gut barrier function. Both fibers upregulate bile acid biosynthesis, but BC's non-fermentable nature leads to higher bile acid excretion, while GG's fermentation causes lower excretion and broader liver metabolic changes. Both fibers reduce body weight, fat accumulation, and cholesterol levels, highlighting their potential in managing obesity and metabolic disorders. The complementary effects of BC and GG underscore the importance of fiber diversity for targeted dietary strategies to improve metabolic health.

Intermittent fasting driven different adaptive strategies in Eothenomys miletus (Red-backed vole) at different altitudes: based on the patterns of variations in intestinal microbiota

In the face of global warming, the Eothenomys miletus (Red - backed vole), a species dwelling in highland mountainous regions, is likely to encounter difficulties. Given its restricted mobility, it may struggle with the uncertainty of food resources. In such circumstances, it becomes increasingly crucial for this species to adjust its diverse responses to fulfill its energy requirements. E. miletus specimens were gathered from different altitudes for intermittent fasting (IF) experiments. In these experiments, the specimens underwent random fasting for 3 days within a seven - day cycle. 16 S rDNA sequencing technology, combined with physiological and biochemical assessment methods, was employed to analyze the impacts of IF on gut microorganisms, physiological and biochemical indicators, and the interactions among them. By exploring the adaptive responses of E. miletus to uncertain food resources, which provides novel perspectives on the adaptive strategies of small rodents in the wild during food-scarce periods. The results showed that IF significantly reduced the body mass of E. miletus. Significant correlations were found between various gut microbes and physiological indicators. Under IF conditions, E. miletus at high altitudes experienced a smaller reduction in body mass compared to those at low altitudes. Moreover, the diversity of gut microbes and endemic bacteria in E. miletus at high altitudes varied more than that of low altitudes. The differential response in body mass reduction between high-altitude and low-altitude E. miletus under IF conditions indicated that altitude is an important factor influencing the physiological adaptation of this species to dietary changes. High-altitude E. miletus showed a relatively smaller decrease in body mass, potentially reflecting their better adaptation to environmental stressors over time. Additionally, the greater variation in gut microbe diversity and endemic bacteria in high-altitude E. miletus implied that altitude may shape the gut microbiota, which in turn could be related to their unique physiological adaptations at high altitudes. Overall, E. miletus at high altitude may possess more stable regulatory mechanisms, demonstrating better adaptation under IF conditions. These findings provide valuable insights into the complex interplay between diet, altitude, and gut microbiota in the context of E. miletus physiology, highlighting the importance of considering both environmental and microbial factors in understanding the species' responses to nutritional challenges.​.

Protective Effects of a Polyherbal Mixture on Intestinal Injury via the NF-κB Signaling Pathway and Gut Microbiota Modulation in Hyperuricemic Mice

This study investigated the protective effects of a polyherbal tea (PHT) on intestinal injury in hyperuricemia (HUA) mice and the underlying mechanisms. PHT was orally administered to mice for 49 days, while potassium oxonate and hypoxanthine were administered 7 days after PHT administration and continued for 42 days to cause HUA. Treatment with PHT significantly reduced serum uric acid and blood urea nitrogen levels in HUA mice. It also inhibited liver xanthine oxidase activity and promoted intestinal uric acid excretion through the upregulation of transporters GLUT9 and ABCG2. Intestinal barrier integrity was reinforced, as evidenced by the restoration of the villous structure, reduction in edema, and upregulation of tight junction proteins (occludin, ZO-1) and mucin (MUC2). Moreover, PHT suppressed serum LPS levels and inhibited the NF-κB pathway, leading to a reduction in TNF-α and IL-6 levels in the gut. Gut microbiota analysis revealed PHT reversed dysbiosis, enriching beneficial bacteria like Duncaniella sp. and Heminiphilus faecis. By UPLC-MS analysis, 154 compounds of PHT persisted in the gut, suggesting that these compounds are likely to modulate both intestinal barrier function and gut microbiota. These findings suggest that this PHT may have potential as a functional food for the prevention of hyperuricemia.

Pre-Administration of Saccharomyces boulardii-Derived Postbiotics Effectively Prevents Dextran Sulfate Sodium-Induced Colitis in Mice

Ulcerative colitis (UC) is effectively alleviated by Saccharomyces boulardii (S. boulardii), an important probiotic. Postbiotics, defined as beneficial non-viable microorganisms and/or their components, can potentially improve gut health. In this study, we utilized S. boulardii to prepare postbiotics via freeze-drying and spray-drying methods, characterized the resulting postbiotics, and investigated their efficacy and underlying mechanisms in preventing UC. In a mouse model of UC induced by dextran sulfate sodium (DSS), we found that prevention with two forms of S. boulardii postbiotics alleviated colitis symptoms triggered by DSS, mitigated colon tissue damage, maintained the distribution of intestinal occludin and ZO-1 proteins, and suppressed the secretion and expression of TNF-α, IL-1β, and IL-6 in serum and colon tissues. Additionally, S. boulardii postbiotics mitigated dysbiosis by modulating gut microbiota composition, including the balance between Bacteroidota and Firmicutes (F/B), as well as the levels of Akkermansia, Muribaculaceae, Dubosiella, and Turicibacter. In conclusion, as a novel biotherapeutic agent, S. boulardii postbiotics effectively prevent DSS-induced UC in mice. Compared to live S. boulardii, postbiotics may hold greater potential for UC prevention.

Impact of a High-Fat Diet on the Gut Microbiome: A Comprehensive Study of Microbial and Metabolite Shifts During Obesity

Over the last few decades, the prevalence of metabolic diseases such as obesity, diabetes, non-alcoholic fatty liver disease, hypertension, and hyperuricemia has surged, primarily due to high-fat diet (HFD). The pathologies of these metabolic diseases show disease-specific alterations in the composition and function of their gut microbiome. How HFD alters the microbiome and its metabolite to mediate adipose tissue (AT) inflammation and obesity is not well known. Thus, this study aimed to identify the changes in the gut microbiome and metabolomic signatures induced by an HFD to alter obesity. To explore the changes in the gut microbiota and metabolites, 16S rRNA gene amplicon sequencing and metabolomic analyses were performed after HFD and normal diet (ND) feeding. We noticed that, at taxonomic levels, the number of operational taxonomic units (OTUs), along with the Chao and Shannon indexes, significantly shifted in HFD-fed mice compared to those fed a ND. Similarly, at the phylum level, an increase in Firmicutes and a decrease in Bacteroidetes were noticed in HFD-fed mice. At the genus level, an increase in Lactobacillus and Ruminococcus was observed, while Allobaculum, Clostridium, and Akkermansia were markedly reduced in the HFD group. Many bacteria from the Ruminococcus genus impair bile acid metabolism and restrict weight loss. Firmicutes are efficient in breaking down complex carbohydrates into short-chain fatty acids (SCFAs) and other metabolites, whereas Bacteroidetes are involved in a more balanced or efficient energy extraction. Thus, an increase in Firmicutes over Bacteroidetes enhances the absorption of more calories from food, which may contribute to obesity. Taken together, the altered gut microbiota and metabolites trigger AT inflammation, which contributes to metabolic dysregulation and disease progression. Thus, this study highlights the potential of the gut microbiome in the development of therapeutic strategies for obesity and related metabolic disorders.

Gut microbiome reveals the trophic variation and significant adaption of three sympatric forest-dwelling ungulates on the eastern Qinghai-Xizang Plateau

BACKGROUND

The gut microbiome of herbivorous mammals regulates numerous physiological processes, including digestion and energy metabolism. The complex stomach architecture of ruminants, in conjunction with the metabolic capabilities of their microbiota, confers a considerable adaptive advantage to these animals. Nevertheless, a significant gap persists in comparative studies on the variations in the gut microbiome among sympatric ruminants and their potential adaptive implications. Accordingly, in this study, 16S rRNA gene sequencing and metagenomic approaches were used to analyse the composition and functional attributes of the gut microbiome of sympatric Moschus chrysogaster, Capricornis sumatraensis, and Cervus albirostris inhabiting the eastern periphery of the Qinghai-Xizang Plateau.

RESULTS

The gut microbiome of C. albirostris exhibited a higher diversity than that of M. chrysogaster and C. sumatraensis, whereas those of M. chrysogaster and C. sumatraensis were similar. Although species-specific variations existed among the three mammalian microbiomes, the microbiomes of C. albirostris and C. sumatraensis were more similar, whereas that of M. chrysogaster was markedly distinct. Metagenomic analysis revealed a pattern of functional convergence in the gut microbiome of the three species, with the gut microbiome of C. albirostris exhibiting a pronounced emphasis on carbohydrate metabolism, significantly surpassing that of M. chrysogaster and C. sumatraensis. Compared to the other two species, the gut microbiome of C. sumatraensis presented significantly elevated levels of amino acids and energy metabolism, whereas that of M. chrysogaster presented an increased capacity for 3-hydroxyacyl- [acyl carrier protein]-dehydratase production.

CONCLUSION

These findings suggest that the gut microbiome of sympatric M. chrysogaster, C. sumatraensis, and C. albirostris tend to converge. Metabolic variations within their gut microbiome may result in differential food resource utilisation, potentially indicating significant nutritional and ecological trait characteristics for stable coexistence.

Poly-γ-glutamic acid alleviates slow transit constipation by regulating aquaporin and gut microbes

Slow transit constipation (STC) is a prevalent gastrointestinal disorder caused by colon dysfunction. Poly-γ-glutamic acid (γ-PGA), an anionic polymer known for its moisture retention, degradability, and food safety, was studied for its effects on loperamide-induced STC in mice. Treatment with γ-PGA for one week significantly increased both defecation frequency and fecal water content, with the high-dose group (10 g/kg/d) restoring fecal water content to 34.23%, outperforming the low- (16.16%) and medium-dose (27.08%) groups and exceeding the positive control, PEG, by 1.35 times. γ-PGA enhanced intestinal peristalsis and reduced the expression of inflammatory markers (IL-1β, IL-6, caspase-1, TLR2) and water-electrolyte transport genes (AQP3, AQP4, ENaC-β), while improving the expression of tight junction proteins (Claudin-1, Occludin, ZO-1) damaged by loperamide. Histopathological analyses confirmed γ-PGA's capacity to repair intestinal damage. Additionally, Western Blot analysis indicated reduced AQP3/4 levels in the colon, and molecular docking showed good binding affinity between γ-PGA and AQPs. γ-PGA also positively altered gut microbiota composition. Overall, γ-PGA shows promise in treating STC by modulating aquaporins and gut microbiota.

Temporary dietary fiber depletion prompts rapid and lasting gut microbiota restructuring in mice

Long-term alterations of the gut microbiota and host symbiosis after a dietary perturbation remain insufficiently understood and characterized. In this study, we investigate the impact of temporary dietary fiber depletion in mice that received a diet with reduced fiber content (RFD) for 3 weeks followed by a return to a standard chow diet for 6 weeks, compared to mice that only received a chow diet. Fiber deprivation was accompanied by a reduction of microbiota diversity and an increase in mucolytic and sulfate-reducing bacteria. The activities of enzymes targeting glycans from the host mucus were increased accordingly, while those targeting plant fibers were decreased. On the host side, we report transiently higher quantities of host DNA in feces during the RFD suggesting an impaired gut barrier function. Six weeks after the return to the chow diet, lasting changes in microbiota composition were observed, as exemplified by the replacement of durably depleted amplicon sequence variants close to Duncaniella dubosii by other members of the Muribaculaceae family. The observation of two distinct gut microbial communities in mice under identical environmental and alimentary conditions at the end of the experiment suggests the existence of alternative stable microbiota states.

IMPORTANCE

In this article, the authors explore the impact of a diet with reduced fiber content on the gut microbiota-host symbiosis in a mouse model. More importantly, they examine the resilience of the intestinal symbiosis after the return to a standard (chow) diet. Some of the measured parameters (intestinal barrier impairment and bacterial glycan-degrading enzymatic activities) returned to control values. However, this was not the case for bacterial richness-the number of different bacteria observed-which remained durably reduced. Among related bacteria, some groups receded and remained undetected until 6 weeks after the return to the chow diet while others saw their abundance increase in replacement. The authors find that a temporary fiber deprivation lasting as little as 3 weeks can cause a transition to an alternative stable microbiota state, i.e., a lasting change in intestinal microbiota composition.

Broccoli (Brassica oleracea L. var. italica Planch) alleviates metabolic-associated fatty liver disease through regulating gut flora and lipid metabolism via the FXR/LXR signaling pathway

The increased consumption of dietary fats contributes to the development of MAFLD (metabolic fatty liver disease). The ability of broccoli to enhance lipid metabolism has attracted researchers' attention. Researchers fed C57BL/6 mice a 12-week HFD to ensure the induction of MAFLD. The findings indicated that broccoli floret juice could effectively relieve MAFLD. Broccoli is helpful for reducing weight, blood glucose levels, fat accumulation, and insulin resistance associated with MAFLD and reduces the concentrations of TC, TG, LDL-C, GOT, GPT, IL-1β, IL-6, CCL4, and MCP1. Broccoli can increase the concentration of HDL-C, CAT, GSH-Px, SOD, and T-AOC, relieve inflammation and hepatic and ileum damage, and improve the antioxidant capacity of the body. Also, broccoli can optimize the structure of intestinal flora, promote the growth of Allobaculum, Muribaculaceae, Akkermansia, Eubacterium, and Bacteroides, and reduce bile acid deposition. In addition, the FXR/LXRα signaling system is impacted by broccoli, which is capable of raising the average levels of expression of the Fxr, SHP, and Cyp7a1 genes and proteins and reducing those of the genes for Fasn, Lpin 1, Dgat 2, Scd1, LXRα, and SREBP-1c.

Reproduction in yellow drum (Nibea albiflora): insights from endocrine regulation and intestinal microbiota changes during reproductive season

The yellow drum (Nibea albiflora), a pivotal species within the Sciaenidae family, is economically important in the mariculture along the coastal regions of China. A comprehensive understanding gonadal maturation and spawning processes is crucial for seed production in the artificial propagation of yellow drum. This study investigates serum hormonal fluctuations, gonadal histological features, sex hormone receptor gene expression, and intestinal microbiota composition in both male and female yellow drum during the reproductive season. Twenty individuals were sampled from reproductive stages IV, V, and VI, respectively. During the spawning season, no significant differences were observed in the levels of PROG, E2, and 11-KT across different stages, in both males and females, with no significant sex-based differences. Subsequent analysis indicated a significant upregulation of fshr, lhcgr, and esr expression in the ovary during spawning stages. In contrast, within the testis, the expression levels of fshr, ar, and esr remained relatively constant across different stages, whereas lhcgr expression was markedly higher during the spawning stages compared with prespawning and post-spawning stages. Analysis of intestinal microbiota revealed a predominance of Bacteroidota, Firmicutes, and Proteobacteria, with no significant sex differences. At the class level, the abundances of Alphaproteobacteria, Gammaproteobacteria, and Bacilli exhibited significant fluctuations during the spawning and post-spawning stages in both sexes. At the genus level, g_Muribaculaceae and g_Bacteroides were abundant during spawning stages in both sexes. A Mantel test showed significant positive correlations between PROG levels and the abundances of g_Bacteroides in males. In females, PROG levels were positively correlated with the abundance of g_Prevotella. These findings enhance our understanding of the interplay between reproductive biology and the biological functions of intestinal microbiota in yellow drum broodstock during the reproductive season, thereby laying a foundation for the development of artificial propagation technology in this species.

In vitro digestion of glycoproteins from Porphyra haitanensis: Effects on structure, hypoglycemic activity, and fermentation characteristics

This study was to investigate the fundamental composition and structure, hypoglycemic activity and fermentation characteristics of Porphyra haitanensis glycoprotein (PG) following in vitro simulate gastrointestinal digestion. After in vitro digestion, PG was degraded into peptides, amino acids, and reducing sugars, and the digested PG structure evolved into functional aggregates that were more favorable for regulating intestinal flora. Such aggregated structure might inhibit the accessibility of digestive enzymes and significantly enhanced its hypoglycemic activity. Compared with undigested PG, the inhibition rate of digested PG on α-amylase and α-glucosidase was increased by 4.70 % and 7.69 %, respectively (P < 0.05). Furthermore, digested PG enhanced the abundances of Lactobacillus and Bifidobacterium, etc., which was positive related with the increased secretion of butyric acid, thereby playing a role in regulating intestinal homeostasis and blood glucose homeostasis in the host. Our findings can offer novel perspectives on the regulation of the intestinal flora by glycoproteins during gastrointestinal digestion.

The Bromodomain and Extraterminal Protein Inhibitor Apabetalone Ameliorates Kidney Injury in Diabetes by Regulating Cholesterol Accumulation and Modulating the Gut Microbiota

Introduction

A US Food and Drug Administration-approved new bromodomain (BRD) and extraterminal (BET) bromine domain antagonist called apabetalone, which targets BRD4, has been shown to increase prebeta-1 high-density lipoprotein (HDL) particles, enhance apolipoprotein A-I in both humans and animals, and restore angiogenesis in experimental diabetes. Its action is not however fully known mechanistically. The objective of our research was to investigate the impact of apabetalone on renal damage linked to diabetic kidney disease (DKD).

Methods

This research employed both pharmacological and genetic methods to examine the impact of apabetalone on db/db (BKS. Cg-leprdb/leprdb) mice and human tubular epithelial cells (HK-2).

Results

Here, significant reductions in blood creatinine, urea nitrogen, and urinary albumin-to-creatinine ratio (UACR) levels, serum triglycerides (TGs) and serum total cholesterol (TC), as well as ectopic lipid droplet formation in renal tissue, were seen in the db/db mice following apabetalone therapy. Analysis of the gut microbiota revealed changes in its composition. Significantly, the proportion of Firmicutes to Bacteroidetes decreased, as well as Deferribacterota, indicating a positive influence on lipid metabolism. Untargeted metabolomic analysis indicated that the ABC transporter signaling pathway, implicated in cholesterol metabolism, was enriched. Moreover, peroxisome proliferator-activated receptor gamma (PPARγ)/liver X receptor (LXR)/adenosine triphosphate-binding cassette transporter A1 (ABCA1) protein, and mRNA level, as well as fibrosis-related marker proteins, fibronectin and collagen I were all improved by apabetalone.

Conclusion

Therefore, we suggest that apabetalone showed significant antihyperlipidemic and antifibrotic effects, closely associated with alterations in the gut microbiota and cholesterol metabolism. The results of this investigation provide fresh perspectives on the processes that underlie apabetalone's effects in db/db mice.

Overfeeding and overweight rapidly reprogram inflammatory signaling

Epidemiologic studies have shown a continuous increase in mortality risk associated with overweight, thus highlighting the health risks beginning before the onset of obesity. However, early changes in inflammatory signaling induced by an obesogenic diet remain largely unknown since studies of obesity typically utilize models induced by months of continuous exposure to a high-fat diet. Here, we investigated how short-term overfeeding remodels inflammatory signaling. We developed and characterized a mouse model of overweight induced by seven days of the Western diet enriched in saturated fats and sucrose, compared to the standard, low-fat laboratory diet or a long-term Western diet for 22 weeks. The short-term Western diet caused a median weight gain of 6 %, while the long-term Western diet increased weight by 92 %. Circulating levels of cholesterol, triglycerides, insulin, and leptin were increased by both diets, but only the long-term Western diet caused transaminitis and significant hepatic steatosis. Both models reduced the alpha and beta diversity of the microbiome. Tryptophan metabolism was perturbed by both models; the long-term Western diet also affected histidine and vitamin B6 metabolism. The short-term and long-term Western diets increased expression of TLR4 on peritoneal immune cells and TLR4-driven plasma levels of proinflammatory cytokines comparably, showing one week of the Western diet was sufficient for inducing inflammation typical of chronic obesity. These findings highlight the importance of diet not only in preclinical studies, but also in the clinical care of individuals with inflammatory disorders.

Protective effect of low-dose lactulose in dextran sulfate sodium induced ulcerative colitis model of rats

Although low-dose lactulose has shown a good theoretical foundation for the treatment of ulcerative colitis (UC) in previous studies, the exact effects and mechanism remain unclear. The rats were randomly distributed into 5 groups, i.e., normal drinking water was provided for an initial 14 days in blank control group, 4% dextran sulfate sodium was used for modeling in the remaining 4 groups. During the 15-24th day, rats in the blank control group were administered with 0.9% saline (0.5 ml/d) by gavage. In the rest 4 groups, rats were administered 0.9% saline (0.5 ml/d, UC model), mesalazine (400 mg/kg/d), lactulose (1000 mg/kg/d), and lactulose + mesalazine (two-drug combination) by gavage. In addition to symptoms and pathological changes, serum IL-6, TNF-α, and High-sensitivity C-reactive protein(Hs-CRP) by ELISA analysis, mRNA and protein expression levels of TLR-2, TLR-4, Nuclear factor-κB(NF-κB), IL-6, and TNF-α in colon tissues by RT-qPCR and WB analyses respectively. Meanwhile, short-chain fatty acid(SCFAs) and intestinal flora were analyzed. Low-dose lactulose improved symptoms (diarrhea, blood in stool, weight loss) and pathological inflammation. In addition to serum IL-6, TNF-α, and Hs-CRP, the mRNA and protein expression levels of TLR-2, TLR-4, NF-κB, IL-6 and TNF-α in the colon were down-regulated with the intervention of lactulose.Meanwhile, lactulose decreased the ileocecal PH, increased SCFAs and altered the intestinal flora. Low-dose lactulose may be beneficial to UC by regulating TLRs/NF-κB pathway, reducing ileocecal PH, increasing SCFAs, regulating intestinal flora and improving the intestinal mucosal barrier. Meanwhile, low-dose lactulose and mesalazine may have additive effects upon combination.

Nanopore sequencing of protozoa: Decoding biological information on a string of biochemical molecules into human-readable signals

Biological information is encoded in a sequence of biochemical molecules such as nucleic acids and amino acids, and nanopore sequencing is a long-read sequencing technology capable of directly decoding these molecules into human-readable signals. The long reads from nanopore sequencing offer the advantage of obtaining contiguous information, which is particularly beneficial for decoding complex or repetitive regions in a genome. In this study, we investigated the efficacy of nanopore sequencing in decoding biological information from distinctive genomes in metagenomic samples, which pose significant challenges for traditional short-read sequencing technologies. Specifically, we sequenced blood and fecal samples from mice infected with Trypanosoma brucei, a unicellular protozoan known for its hypervariable and dynamic regions that help it evade host immunity. Such characteristics are also prevalent in other host-dependent parasites, such as bacteriophages. The taxonomic classification results showed a high proportion of nanopore reads identified as T. brucei in the infected blood samples, with no significant identification in the control blood samples and fecal samples. Furthermore, metagenomic de novo assembly of these nanopore reads yielded contigs that mapped to the reference genome of T. brucei in the infected blood samples with over 96 % accuracy. This exploratory work demonstrates the potential of nanopore sequencing for the challenging task of classifying and assembling hypervariable and dynamic genomes from metagenomic samples.

Perturbations in the gut microbiome of C57BL/6 mice by the sobriety aid Antabuse® (disulfiram)

AIMS

Disulfiram (Antabuse®) is an oral alcohol sobriety medication that exhibits antimicrobial activity against Gram-positive facultative anaerobes. The aims of this study were to measure the antimicrobial activity against anaerobic bacteria of the gut human microbiome and establish the extent that disulfiram alters the microbial composition of the ileum, cecum, and feces using C57BL/6 mice.

METHODS AND RESULTS

Antimicrobial susceptibility testing by the microdilution method revealed that disulfiram inhibits the in vitro growth of gut anaerobic species of Bacteroides, Clostridium, Peptostreptococcus, and Porphyromonas. Differential sequencing of 16S rRNA isolated from the ileum, cecum, and feces contents of treated vs. untreated mice showed that disulfiram enriches the Gram-negative enteric population. In female mice, the enrichment was greatest in the ileum, whereas the feces composition in male mice was the most heavily altered.

CONCLUSIONS

Daily administration of oral disulfiram depletes the enteric Gram-positive anaerobe population as predicted by the minimum inhibitory concentration data for isolates from the human gut microbiota.

Ginseng-derived GABAFG ameliorates type 2 diabetes mellitus by modulating autophagy-lysosome pathway and gut microbiota

INTRODUCTION

Hyperglycemia and hyperlipidemia are the hallmarks of type 2 diabetes mellitus (T2DM). T2DM is a systemic metabolic disease caused by insulin resistance and malfunctioning pancreatic β-cells. Although ginseng (the roots of Panax ginseng C.A. Meyer) can be used to treat T2DM, the underlying mechanism is unclear.

OBJECTIVES

To assess the role and mechanism of, γ-aminobutyric acid-fructosyl-glucose (GABAFG), a maillard reaction product of ginseng, in T2DM treatment.

METHODS

The metabolism of GABAFG in serum and tissues was analyzed via ultra-high performance liquid chromatography-Q exactive-mass spectrometry (UHPLC-QE-MS). The molecular mechanisms of GABAFG in pancreatic β-cells (in vivo and in vitro) were investigated via Western blotting, qPCR and immunofluorescence. In addition, the results were validated via high-throughput sequencing and serum metabolomics.

RESULTS

GABAFG alleviated the elevation of blood glucose and blood lipids in HFD/STZ-induced T2DM mice. Also, GABAFG reduced the insulin resistance-associated IRS-1 signaling axis in pancreatic β-cells in vitro. Mechanistically, GABAFG targeted the nuclear translocation of TFEB inhibited apoptosis of pancreatic β-cells by enhancing autophagolysosome function. In addition, GABAFG remodeled the gut microbiota. Specifically, GABAFG increased Akkermansia, decreased Romboutsia abundance, and decreased serum glycerophospholipid metabolism, thus alleviating T2DM-induced dyslipidemia.

CONCLUSION

This is the first study to assess the pharmacological effects of ginseng-derived GABAFG in T2DM. Therefore, this study provides a new theoretical basis for understanding ginseng effect in metabolic diseases.

Effects of dietary supplementation with linseed oil, Ascophyllum nodosum or treated A. nodosum on animal performance, gaseous emissions, ruminal fermentation and microbiota, and meat quality in growing dairy-beef bulls

Oils high in polyunsaturated fatty acids (PUFA) and seaweeds containing phlorotannins have potential anti-methanogenic effects in ruminants. This study assessed the potential of dietary supplementation with linseed oil, Ascophyllum nodosum or treated A. nodosum in an intensive beef cattle feeding system on animal performance, gaseous emissions, ruminal fermentation and microbiota, and muscle fatty acid profiles. Seventy-two dairy-beef bulls (380 kg; 11 mo of age) were randomly allocated to one of four dietary treatments (n = 18) for a 70-d period. The diet consisted of a 60:40 grass silage:concentrate ratio. Silage was offered daily (0900 hours) and concentrates were offered twice daily (0800 and 1500 hours). Dietary treatments were incorporated into the concentrate portion of the diet as follows; 1) CON (no supplementation), 2) LSO (linseed oil), 3) SW (A. nodosum), and 4) EX (A. nodosum extract), included to target 0%, 4%, 2%, and 2% of dry matter intake (DMI), respectively. The concentrates were formulated to be isonitrogenous across the 4 treatment groups. Total DMI (American Calan Inc., Northwood, NH), average daily gain (ADG), gain:feed, and enteric emissions (GreenFeed; C-Lock Inc., Rapid City, SD) were measured for the 70-d supplementation period. Total DMI (P = 0.17), ADG (P = 0.28), gain:feed (P = 0.68), and total tract digestibility (P = 0.70) did not differ across treatments. Daily methane production (P < 0.001) for CON, LSO, SW, and EX was 210, 170, 202, and 193 g/d, respectively, resulting in reductions of 19% and 8% for LSO and EX, respectively, relative to CON. Ruminal fermentation parameters show that LSO was the only dietary treatment to increase propionate (P = 0.09) and decrease butyrate (P = 0.04) concentrations relative to CON. Microbial analyses showed LSO supplementation increased and decreased relative abundances of fungal genera Buwchfawromyces and Piromyces, respectively, while altering relative abundances of the bacterial genera Muribaculaceae, Bacteroidales RF16 group and Bacterium F082. Additionally, LSO increased linolenic acid (P < 0.001) and n-3 PUFA (P < 0.001) concentration of the longissimus dorsi muscle compared to CON, SW, and EX. In conclusion, LSO was the most effective dietary supplementation strategy compared to CON, EX, and SW, whereby it reduced methane emissions, modified ruminal fermentation and microbial profiles, and enhanced beneficial muscle PUFA concentration, without impacting animal performance.

Comparative analysis of barley dietary fiber fermented with and without Lactiplantibacillus plantarum dy-1 in promoting gut health and regulating hepatic energy metabolism in high-fat diet-induced obese mice

A previous study has revealed that Lactiplantibacillus plantarum (Lp. plantarum) dy-1 fermentation changed the structural properties and in vitro fecal fermentation characteristics of barley dietary fiber. However, the health-promoting effects of fermented dietary fiber in vivo remained unclear. This study was aimed at comparing the ameliorative effects of barley dietary fiber fermented with or without Lp. plantarum dy-1 on lipid metabolism, gut microbiota composition and hepatic energy metabolism. After a twelve-week intervention, fermented barley dietary fiber (FBDF) reduced the body weight and fat accumulation in liver and epididymal white adipose tissue, improved HFD-induced hyperlipidemia and glucose intolerance, and increased short chain fatty acid (SCFA) levels, exhibiting effects that were better than those of raw barley dietary fiber (RBDF). FBDF supplementation improved the gut microbiota composition, specifically enhancing the abundance of probiotic and SCFA-producing bacteria, such as Akkermansia and Muribaculaceae, while RBDF exhibited regulatory effects on harmful bacteria (Escherichia-Shigella and Desulfovibrionaceae). Additionally, FBDF up-regulated the expression of genes related to energy metabolic processes, such as aerobic respiration and oxidative phosphorylation, inhibited the genes related to lipid biosynthetic metabolism, and improved the activities of hepatic energy metabolism-related enzymes, demonstrating effects that were better than those of RBDF. Therefore, this study indicated the potential of using FBDFs as healthy food resources to prevent obesity or as prebiotics to improve gut microbiota.

Dietary protein source alters gut microbiota composition and function

The source of protein in a person's diet affects their total life expectancy. However, the mechanisms by which dietary protein sources differentially impact human health and life expectancy are poorly understood. Dietary choices impact the composition and function of the intestinal microbiota that ultimately modulate host health. This raises the possibility that health outcomes based on dietary protein sources might be driven by interactions between dietary protein and the gut microbiota. In this study, we determined the effects of seven different sources of dietary protein on the gut microbiota of mice using an integrated metagenomics-metaproteomics approach. The protein abundances measured by metaproteomics can provide microbial species abundances, and evidence for the molecular phenotype of microbiota members because measured proteins indicate the metabolic and physiological processes used by a microbial community. We showed that dietary protein source significantly altered the species composition and overall function of the gut microbiota. Different dietary protein sources led to changes in the abundance of microbial proteins involved in the degradation of amino acids and the degradation of glycosylations conjugated to dietary protein. In particular, brown rice and egg white protein increased the abundance of amino acid degrading enzymes. Egg white protein increased the abundance of bacteria and proteins usually associated with the degradation of the intestinal mucus barrier. These results show that dietary protein sources can change the gut microbiota's metabolism, which could have major implications in the context of gut microbiota mediated diseases.

Muribaculum intestinale restricts Salmonella Typhimurium colonization by converting succinate to propionate

Insufficient dietary fiber intake is associated with dysbiosis and compromised colonization resistance (CR) to enteric infections. However, a detailed understanding of the relationship between dietary fiber insufficiency and CR remains elusive. Our study aimed to delineate the impact of fiber deprivation on gut microbiome and CR in a murine model with Salmonella Typhimurium infection. Our findings indicate that dietary fiber deprivation resulted in impaired CR and depletion of commensal bacteria Muribaculaceae. By combining dietary switch, FMT, and genomic analysis, we identify Muribaculum intestinale as a candidate bacterium, capable of converting succinate into propionate. Oral administration of Muribaculum intestinale augmented CR to Salmonella Typhimurium, accompanied by succinate reduction and propionate elevation. Dietary supplementation of propionate, but not succinate, enhanced CR to Salmonella Typhimurium in mice consuming a fiber-free diet. Taken together, our research identified a crucial metabolic pathway encoded by gut microbiome underlying CR, providing an intervention strategy for combatting enteric infections among Western diet-consuming populations.

Oral administration of Bifidobacterium longum and Bifidobacterium infantis ameliorates cefcapene pivoxil-induced attenuation of anti-programmed cell death protein-1 antibody action in mice

Gut bacteria play pivotal roles in the antitumor effects of immune checkpoint inhibitors (ICIs). However, antimicrobial therapy, often necessary for infections in cancer patients, can reduce the efficacy of ICIs. The potential of probiotics to restore ICI efficacy remains uncertain. This study evaluated the effects of Bifidobacterium longum and Bifidobacterium infantis (BLBI) in a CT-26 subcutaneous tumor mouse model treated with anti-programmed cell death protein 1 antibody (αPD-1) and cefcapene pivoxil (CFPN-PI). BALB/c mice received daily oral gavage of CFPN-PI for 5 days before tumor inoculation, followed by weekly αPD-1 administration and tumor growth monitoring. BLBI was administered via ad libitum feeding, mixed in powdered feed. Gut microbiota composition and fecal short-chain fatty acid concentrations were assessed, along with gene expression and immune cell populations in the tumor microenvironment, using quantitative RT-PCR and flow cytometry, respectively. CFPN-PI alone increased tumor growth and attenuated the antitumor effect of αPD-1. In contrast, BLBI inhibited CFPN-PI-induced tumor growth and improved the efficacy of αPD-1. Probiotic treatment increased the stool propionic acid concentration and the number of tumor-infiltrating conventional type 1 dendritic cells. Relative decreases in Bacteroides and Lachnospiraceae _NK4A136_group species and relative increases in Muribaculaceae and Unclassified_f_Oscillospiraceae species correlated with an improved αPD-1 response. These results suggest that probiotic administration may be a new therapeutic strategy to rescue the attenuated efficacy of ICIs in patients with cancer who require antimicrobial therapy.

Akkermansia muciniphila Promotes SIgA Production and Alters the Reactivity Toward Commensal Bacteria in Early-Weaned Piglets

BACKGROUND

Secretory IgA (SIgA) is the first line of defense in protecting the intestinal epithelium against pathogenic bacteria, regulating gut microbiota composition, and maintaining intestinal homeostasis. Early weaning strategies may disrupt SIgA levels in piglet intestines, causing a decline in immune response and early weaning stress. However, the specific microbial mechanisms modulating SIgA in early-weaned piglets are not well understood.

OBJECTIVES

We hypothesized that Akkermansia muciniphila increases intestinal SIgA production in the early-weaned piglets.

METHODS

Fecal SIgA levels, SIgA-coated bacteria abundance, and fecal metagenomes were compared between 6 Huanjiang miniature (HM) and 6 Duroc×Landrace×Yorkshire (DLY) early-weaned piglets to identify bacterial species involved in SIgA modulation. Four bacterial species were investigated using 5 groups (Control, A. muciniphila, L. amylovorus, L. crispatus, and L. acidophilus) of male specific pathogen-free C57BL/6J mice, weaned 3 wk postbirth (n = 8/group). Subsequently, 10-d-old Landrace×Yorkshire (LY) piglets were randomly assigned to 3 groups (Control, 109A. muciniphila, and 108A. muciniphila) (n = 10/group) to evaluate the effect of orally administered A. muciniphila on intestinal SIgA production and microbial composition.

RESULTS

HM early-weaned piglets showed significantly higher SIgA levels [7.59 μg/mg, 95% confidence interval (CI): 3.2, 12, P = 0.002] and SIgA-coated bacteria abundance (8.64%, 95% CI: 3.2, 14, P = 0.014) than DLY piglets. In the mouse model, the administration of A. muciniphila significantly increased SIgA levels (3.50 μg/mg, 95% CI: 0.59, 6.4, P = 0.018), SIgA-coated bacteria abundance (9.06%, 95% CI: 4, 14, P = 0.018), and IgA+ plasma cell counts (6.1%, 95% CI: 4.3, 8, P = 0.005). In the pig experiments, the oral administration of A. muciniphila to LY piglets significantly enhanced intestinal SIgA concentrations (4.22 μg/mg, 95% CI: 0.37, 8.5, P = 0.034) and altered the SIgA-coated bacterial landscape.

CONCLUSIONS

Early intervention with A. muciniphila in nursing piglets can increases intestinal SIgA production and alter the reactivity toward commensal bacteria upon early weaning.

Investigation of Intestinal Microbes of Five Zokor Species Based on 16S rRNA Sequences

Zokor is a group of subterranean rodents that are adapted to underground life and feed on plant roots. Here, we investigated the intestinal microbes of five zokor species (Eospalax cansus, Eospalax rothschildi, Eospalax smithi, Myospalax aspalax, and Myospalax psilurus) using 16S amplicon technology combined with bioinformatics. Microbial composition analysis showed similar intestinal microbes but different proportions among five zokor species, and their dominant bacteria corresponded to those of herbivores. To visualize the relationships among samples, PCoA and PERMANOVA tests showed that the intestinal microbes of zokors are largely clustered by host species, but less so by genetics and geographical location. To find microbes that differ among species, LefSe analysis identified Lactobacillus, Muribaculaceae, Lachnospiraceae_NK4A136_group, unclassified_f_Christensenellaceae, and Desulfovibrio as biomarkers for E. cansus, E. rothschildi, E. smithi, M. aspalax, and M. psilurus, respectively. PICRUSt metagenome predictions revealed enriched microbial genes for carbohydrate and amino acid metabolism in E. cansus and E. smithi, and for cofactor and vitamin metabolism as well as glycan biosynthesis and metabolism in E. rothschildi, M. aspalax, and M. psilurus. Our results demonstrated differences in the microbial composition and functions among five zokor species, potentially related to host genetics, and host ecology including dietary habits and habitat environment. These works would provide new insight into understanding how subterranean zokors adapt to their habitats by regulating intestinal microbes.

Blended phytogenics as an alternative to growth-promoting antibiotics in newly weaned piglets

The research aimed to evaluate the effects of a commercial blend of phytogenic compounds on the digestibility, antioxidant system, intestinal microbiota, and performance of weaned piglets. Two experiments compared three treatments (diets): control, zinc bacitracin (300 g/t) and blended phytogenic compounds (400 g/t). The first experiment analised of digestibility of the dry matter, organic matter, crude protein, crude energy and metabolizable energy, in addition to blood parameters and gut microbiota in 15 piglets commercial cross-bred, weaned at 28 days of age, castrated males, weighing 9.40 ± 0.622 kg housed in metabolic cages. In the second experiment, performance was evaluated on 108 piglets commercial cross-bred, weaned at 26 days of age, females and castrated males, weighing 7.52 ± 0.356 kg housed in collective stalls with 1,5 m² (3 animals/stall). A completely randomized design was used. The data were subjected to analysis of variance, and the means compared by the Tukey test at 5% significance. There were no differences in piglet digestibility and performance. There was a reduction in the levels of the enzyme superoxide dismutase, lipid peroxidation, and haptoglobulin, and an increase in the levels of the non-protein thiol compound and IgA for the animals receiving the phytogenic compound when compared with the piglets of the other treatments (p < 0.05). A tendency in diversity was observed in the intestinal microbiota of piglets receiving the phytogenic compound in the feed (p = 0.054). Due to its important role in the antioxidant system and intestinal microbiota, it is suggested that the blend of phytogenic additives can replace antibiotics growth promoters in the diet of newly weaned piglets.

Targeting quorum sensing for manipulation of commensal microbiota

Bacteria communicate through the accumulation of autoinducer (AI) molecules that regulate gene expression at critical densities in a process called quorum sensing (QS). Extensive work using simple systems and single strains of bacteria have revealed a role for QS in the regulation of virulence factors and biofilm formation; however, less is known about QS dynamics among communities, especially in vivo. In this review, we summarize the diversity of QS signals as well as their ability to influence "non-target" behaviors among species that have receptors but not synthases for those signals. We highlight host-microbe interactions facilitated by QS and describe cross-talk between QS and the mammalian endocrine and immune systems, as well as host surveillance of QS. Further, we describe emerging evidence for the role of QS in non-infectious, chronic, microbially associated diseases including inflammatory bowel diseases and cancers. Finally, we describe potential therapeutic approaches that involve leveraging QS signals as well as quorum quenching approaches to block signaling in vivo to mitigate deleterious consequences to the host. Ultimately, QS offers a previously underexplored target that may be leveraged for precision modification of the microbiota without deleterious bactericidal consequences.

The Impact of Fermentation Methods on the Quality and Bacterial Diversity of Dazhu Glutinous Rice Wine

Dazhu glutinous rice wine is a well-known traditional Chinese rice wine, and many local factories and handicraft workshops use different fermentation methods to produce it. Still, the influence of fermentation processes on glutinous rice wine is unclear. This study aimed to compare the difference between the two fermentation methods in the quality and bacterial composition of Dazhu glutinous rice wine. Results showed that the alcoholic content (P < 0.0001) and acidity (P < 0.01) in the rice wine fermented after packaging (PFRW) were higher than in the rice wine packaged after fermentation (FPRW), but the total sugar content was lower. Most amino, such as glutamic acid proline, and lactic acid were significantly higher in FPRW (P < 0.0001). In addition, the aroma, flavor and taste were better in FPRW than in PFRW. The Limosilactobacillus fermentum, Pediococcus pentosaceus, and Lactococcus lactis were dominant bacteria in FPRW, positively associated with amino acid and lactic acid. At the same time, Alcaligenaceae and Pedobacter nutriment were dominant bacteria in PFRW and negatively correlated with the quality. These implied that lactic acid bacteria significantly contributed to accumulating flavor ingredients and improving the quality of Dazhu glutinous rice wine. This study provides reference data for improving the quality of rice wine.

FGF20 modulates gut microbiota to mitigate dextran sodium sulfate-induced ulcerative colitis in mouse models

Ulcerative colitis (UC), a prevalent form of inflammatory bowel disease (IBD), presents a significant clinical challenge due to the lack of optimal therapeutic strategies. Emerging evidence suggests that fibroblast growth factor 20 (FGF20) may play a crucial role in mitigating UC symptoms, though the mechanistic underpinnings remain elusive. In this study, a mouse model of UC was established using dextran sodium sulfate (DSS) to investigate the potential role of FGF20. Our findings revealed a marked reduction in FGF20 expression in the serum and colonic tissues of DSS-treated mice. Furthermore, FGF20 knockout did not exacerbate colonic damage in these mice. Conversely, overexpression of FGF20 via adeno-associated virus (AAV) significantly alleviated UC-associated symptoms. This alleviation was evidenced by attenuated intestinal shortening, mitigated weight loss, increased colonic goblet cell density and crypt formation, reduced inflammation severity and inflammatory cell infiltration, and enhanced expression of tight junction and mucin proteins. Moreover, FGF20 significantly ameliorated the dysbiosis of gut microbiota in DSS-treated mice by increasing the abundance of beneficial bacteria and decreasing the abundance of harmful bacteria. The beneficial effects of FGF20 were notably attenuated following gut microbiota depletion with an antibiotic regimen. Fecal microbiota transplantation experiments further supported the critical role of gut microbiota in mediating the effects of FGF20 on DSS-treated mice. In conclusion, these findings highlight the potential involvement of gut microbiota in the therapeutic effects of FGF20 in UC.

The Prophylactic Protection of Salmonella Typhimurium Infection by Lentilactobacillus buchneri GX0328-6 in Mice

Salmonellosis is a disease caused by non-typhoid Salmonella, and although some lactic acid bacteria strains have been shown previously to relieve Salmonellosis symptoms, little has been studied about the preventive mechanism of Lentilactobacillus buchneri (L. buchneri) against Salmonella infection in vivo. Therefore, the L. buchneri was fed to C57BL/6 mice for 10 days to build a protective system of mice to study its prevention and possible mechanisms. The results showed that L. buchneri GX0328-6 alleviated symptoms caused by Salmonella typhimurium infection among C57BL/6 mice, including low survival rate, weight loss, increase in immune organ index and hepatosplenomegaly, and modulated serum immunoglobulin levels and intrinsic immunity. Importantly, the L. buchneri GX0328-6 enhanced the mucosal barrier of the mouse jejunum by upregulating the expression of tight junction proteins such as ZO-1, occludins, and claudins-4 and improved absorptive capacity by increasing the length of mouse jejunal villus and the ratio of villus length to crypt depth and decreasing the crypt depth. L. buchneri GX0328-6 reduced the intestinal proliferation and invasion of Salmonella typhimurium by modulating the expression of antimicrobial peptides in the intestinal tract of mice, and reduced intestinal inflammation and systemic spread in mice by downregulating the expression of IL-6 and promoting the expression of IL-10. Furthermore, L. buchneri GX0328-6 increased the relative abundance of beneficial bacteria colonies and decreased the relative abundance of harmful bacteria in the cecum microflora by modulating the microflora in the cecum contents.

Development of a novel complex inflammatory bowel disease mouse model: Reproducing human inflammatory bowel disease etiologies in mice

Inflammatory bowel disease (IBD), caused by environmental factors associated with the host's genetic traits, is represented by Crohn's disease and ulcerative colitis. Despite the increasing number of patients with IBD, the current treatment is limited to symptomatic therapy. A complex IBD model mimicking the human IBD etiology is required to overcome this limitation. Herein, we developed novel complex IBD models using interleukin 2 receptor subunit gamma (Il2rg)-deficient mice, high-fat diet, dextran sodium sulfate, and Citrobacter rodentium. The more IBD factors applied complexly, colon length shortened and inflammation worsened. The levels of pro-inflammatory cytokines increased with increased IBD factors. Anti-inflammatory cytokine decreased in all factors application but increased in Il2rg deficiency and Westernized diet combination. Additionally, the pro-inflammatory transcription factors and leaky intestinal epithelial marker were upregulated by a combination of IBD factors. Species diversity decreased with IBD factors. Phylogenetic diversity decreased as IBD factors were applied but increased with combined Il2rg deficiency and Westernized diet. The more IBD factors applied complexly, the more severe the dysbiosis. Finally, we developed a novel complex IBD model using various IBD factors. This model more closely mimic human IBD based on colonic inflammation and dysbiosis than the previous models. Based on these results, our novel complex IBD model could be a valuable tool for further IBD research.

Effects of Yucca Extract on Nutrient Digestibility, Antioxidant Status, Estrus and Faecal Microorganism in Gilts

The objective of this study was to investigate the effects of yucca extract (YE) supplementation on estrus, nutrient digestibility, antioxidant capacity and fecal microorganisms of gilts. Twenty gilts were randomly divided into two groups: basal diet (CONT) and basal diet + 0.25 g/kg YE (YETG). The results showed that supplementing 0.25 g/kg YE in the diet of gilts significantly increased the apparent digestibility of dietary energy, crude fat and crude protein (p < 0.05). In addition, YE could also improve the antioxidant capacity of gilts, significantly increase the serum total antioxidant capacity (T-AOC) activity and decrease the malondialdehyde (MDA) content of gilts (p < 0.05). In terms of fecal microorganisms, YE significantly increased the Shannon index and Simpson index of fecal microorganisms of gilts (p < 0.05), decreased the abundance of Proteobacteria, Actinobacteriota and Streptococcus sp., and increased the abundance of Muribaculaceae and Prevotalla sp. in the feces of gilts (p < 0.05). In conclusion, dietary YE increased the apparent digestibility of nutrients, improved the antioxidant status of gilts and increased the α diversity of fecal microorganisms. These results provide a reference for the application of YE in gilts production.

High-fat diet stimulated butyric acid metabolism dysbiosis, altered microbiota, and aggravated inflammatory response in collagen-induced arthritis rats

BACKGROUND

Research has demonstrated that obesity may be associated with rheumatoid arthritis (RA). In addition, Dysbiosis of intestinal microbiota and their metabolites has been linked to the occurrence and development of RA and obesity. However, the mechanism by which obesity affects RA remains unclear.In this study, we explored the impact of high fat diet(HFD) on collagen-induced arthritis (CIA) rats and revealed its mechanisms based on gut microbiota and metabolomics.

METHODS

Based on diet and modeling, rats were divided into normal group (Con), CIA model group, HFD group (HFD), and HFD + CIA group (HCIA). The effect of HFD on arthritis in CIA rats were investigated based on the arthritis index (AI), weight, blood lipid levels, and inflammatory cytokines. Moreover, HE staining and micro-CT were performed to evaluated the effect of HFD on the pathology of joints and synovial tissues in CIA rats.16S rRNA amplicon sequencing and liquid chromatography-mass spectrometry (LC-MS) were employed to explore changes in gut microbiota and short-chain fatty acids (SCFAs).

RESULTS

The AI scores, inflammatory cytokines and bone destruction parameters in the HCIA group were significantly higher than those in the other three groups. The results of 16S rRNA amplicon sequencing and metabolomics showed that compared with the other three groups, the expression of g_Muribaculaceae and butyric acid were reduced in the HCIA group. Spearman and linear correlation analyses revealed a positive correlation between g_Muribaculaceae abundance and butyric acid levels.

CONCLUSIONS

HFD stimulated butyric acid metabolism dysbiosis, altered microbiota, and aggravated inflammatory response in CIA rats.

Limosilactobacillus fermentum KBL674 Alleviates Vaginal Candidiasis

Candida albicans (C. albicans) is the primary etiologic agent of vaginal candidiasis. Lactobacillus species are predominant in the vaginal microbiome; they inhibit the development of vaginal candidiasis by producing antimicrobial agents, such as lactic acid and hydrogen peroxide. In this study, we investigated the effects of Limosilactobacillus fermentum (L. fermentum) KBL674 in a mouse model of vaginal candidiasis. L. fermentum KBL674 inhibited C. albicans hyphal growth. Moreover, oral administration of L. fermentum KBL674 significantly suppressed vaginal C. albicans infection and associated symptoms, including tissue thickness and immune cell infiltration. A substantial quantity of L. fermentum KBL674 was excreted by the mice within 6 h after oral administration, indicating that most L. fermentum KBL674 did not settle within the gastrointestinal tract. L. fermentum KBL674 modulated gut microbiome diversity, increasing abundances of the genera Akkermansia, Eubacterium, and Faecalibaculum and family Muribaculaceae. Abundances of these bacteria showed negative correlations with the vaginal C. albicans burden in the mouse model, suggesting links between the gut microbiome composition and the vaginal C. albicans burden. Therefore, L. fermentum KBL674 can reduce the vaginal C. albicans burden via direct or indirect inhibition and modulation of the gut microbiome composition preventively.

Fermented soybean meal modified the rumen microbiota and increased the serum prolactin level in lactating Holstein cows

This study aimed to investigate the effects of fermented soybean meal (FSM) on milk production, blood parameters, and rumen fermentation and microbial community in dairy cows. In this study, 48 healthy Holstein cows (parity, 3.0 ± 0.6; days in milk, 86.0 ± 6.7) were used. Cows were randomly assigned into four groups (CON, T-200, T-400, and T-600) with 12 cows per group. Cows in CON were not supplemented with FSM. Cows in T-200, T-400, and T-600 were supplemented with 200, 400, and 600 g/head/day FSM, respectively. This study lasted 5 weeks (1-week adaptation and 4-week treatment). The results showed that FSM did not affect milk yield and milk components (p > 0.05). In the serum, FSM greatly increased prolactin (p < 0.01), and a dosage effect was observed. Aspartate aminotransferase and total protein were the highest in the T-400 (p < 0.05), and triglycerides was the lowest in T-200 (p < 0.05), and there was no difference for the 3 measurements between the other 3 groups (p > 0.05). In the rumen, FSM did not affect pH, microbial crude protein, acetate, propionate, butyrate, valerate, total volatile fatty acids and the ratio of acetate:propionate (p > 0.05), only changed NH3-N, isobutyrate and isovalerate (p < 0.05). The results of the rumen bacterial 16S rRNA genes sequencing showed that FSM decreased the richness (p < 0.05) and evenness (p < 0.05) of the bacterial communities. PCoA analysis showed that FSH altered the rumen bacterial community (ANOSIM, R = 0.108, p = 0.002). In the relative abundance of phyla, FSM increased Firmicutes (p = 0.015) and Actinobacteriota (p < 0.01) and Patescibacteria (p = 0.012), decreased Bacteroidota (p = 0.024). In the relative abundance of genera, FSM increased Christensenellaceae R-7 group (p = 0.011), Lactococcus (p < 0.01), Candidatus Saccharimonas (p < 0.01), Olsenella (p < 0.01), decreased Muribaculaceae_norank (p < 0.01). Conclusively, supplemented FSM altered the rumen fermentation parameters and bacterial community, and increased serum prolactin level in lactating Holstein cows. These findings may provide an approach to keep the peak of lactation in dairy cows.