Fecal Microbiota Research Articles

Safety and Efficacy of Fecal Microbiota, Live-jslm (REBYOTA®), for the Prevention of Recurrent Clostridioides difficile Infection in Participants With Inflammatory Bowel Disease in PUNCH CD3-OLS.

Fecal microbiota, live-jslm (RBL; REBYOTA®), is the first single-dose, broad consortia, microbiota-based live biotherapeutic approved by the US Food and Drug Administration to prevent recurrent Clostridioides difficile infection (rCDI) in adults following standard-of-care antimicrobials. Inflammatory bowel disease (IBD) is a common risk factor for rCDI, yet patients with IBD are often excluded from prospective trials. This subgroup analysis of PUNCH CD3-OLS (NCT03931941) evaluated the safety and efficacy of RBL in participants with rCDI and IBD. Participants with IBD (ulcerative colitis [UC], Crohn's disease [CD], or unspecified) who had rCDI were included. Treatment-emergent adverse event (TEAE) data were collected for up to 6 months following RBL administration. Efficacy outcomes included treatment success at 8 weeks and sustained clinical response at 6 months. Overall, 793 participants were enrolled, and 697 received RBL; 74 had IBD (UC: n = 45; CD: n = 25; unspecified IBD: n = 4). TEAEs within 8 weeks of administration were reported by 45.9% and 47.5% of participants with and without IBD, respectively; most were mild or moderate gastrointestinal symptoms. Serious TEAEs within 8 weeks of administration were reported by 1.4% and 4.2% of participants with and without IBD, respectively. The treatment success rate at 8 weeks was 78.9%, and the sustained clinical response rate at 6 months was 91.1% in participants with IBD, similar to rates in participants without IBD (73.2% and 91.0%, respectively). The results of this subgroup analysis of PUNCH CD3-OLS suggest RBL is safe and efficacious in patients with IBD.

Microbiota and immune dynamics in rheumatoid arthritis: Mechanisms and therapeutic potential.

Rheumatoid arthritis (RA) is a complex autoimmune disease with growing evidence implicating the microbiota as a critical contributor to its pathogenesis. This review explores the multifaceted roles of microbial dysbiosis in RA, emphasizing its impact on immune cell modulation, autoantibody production, gut barrier integrity, and joint inflammation. Animal models reveal how genetic predisposition and environmental factors interact with specific microbial taxa to influence disease susceptibility. Dysbiosis-driven metabolic disruptions, including alterations in short-chain fatty acids and bile acids, further exacerbate immune dysregulation and systemic inflammation. Emerging therapeutic strategies-probiotics, microbial metabolites, fecal microbiota transplantation, and antibiotics-offer innovative avenues for restoring microbial balance and mitigating disease progression. By integrating microbiota-targeted approaches with existing treatments, this review highlights the potential to revolutionize RA management through precision medicine and underscores the need for further research to harness the microbiota's therapeutic potential.

Microbiome characterization of patients with Crohn disease and the use of fecal microbiota transplantation: A review.

Inflammatory bowel disease is a chronic inflammatory condition predominantly affecting the intestines, encompassing both ulcerative colitis and Crohn disease (CD). As one of the most common gastrointestinal disorders, CD's pathogenesis is closely linked with the intestinal microbiota. Recently, fecal microbiota transplantation (FMT) has gained attention as a potential treatment for CD, with the effective reestablishment of intestinal microecology considered a crucial mechanism of FMT therapy. This article synthesizes the findings of population-based cohort studies to enhance our understanding of gut microbial characteristics in patients with CD. It delves into the roles of "beneficial" and "pathogenic" bacteria in CD's development. This article systematically reviews and compares data on clinical response rates, remission rates, adverse events, and shifts in bacterial microbiota. Among these studies, gut microbiome analysis was conducted in only 7, and a single study examined the metabolome. Overall, FMT has demonstrated a partial restoration of typical CD-associated microbiological alterations, leading to increased α-diversity in responders and a moderate shift in patient microbiota toward the donor profile. Several factors, including donor selection, delivery route, microbial state (fresh or frozen), and recipient condition, are identified as pivotal in influencing FMT's effectiveness. Future prospective clinical studies with larger patient cohorts and improved methodologies are imperative. In addition, standardization of FMT procedures, coupled with advanced genomic techniques such as macroproteomics and culture genomics, is necessary. These advancements will further clarify the bacterial microbiota alterations that significantly contribute to FMT's therapeutic effects in CD treatment, as well as elucidate the underlying mechanisms of action.

Protocol for oral fecal gavage to reshape thegutmicrobiota in mice.

Fecal microbiota transplantation (FMT) is clinically applied, while oral FMT (oral fecal gavage [OFG]) is preferred for experimental mice. Here, we present a protocol for OFG in antibiotic-pretreated mice, demonstrating the progressive, time-dependent evolution of the gut microbiota in the recipients. We describe steps for fecal sample collection and preparation procedures, oral gavage, and monitoring gut microbiota changes. This protocol serves as a general guide forreshaping the gut microbiota in recipient mice for various experimental applications. For complete details on the use and execution of this protocol, please refer to Yang etal.1.

Sargassum fusiforme polysaccharides protect mice against Citrobacter rodentium infection via intestinal microbiota-driven microRNA-92a-3p-induced Muc2 production.

Sargassum fusiforme, widely consumed in Asian countries, has been proven to have various biological activities. However, the impacts and mechanisms of Sargassum fusiforme polysaccharides (SFPs) on intestinal bacterial infection are not yet fully understood. Our findings indicate that SFPs pretreatment ameliorates intestinal inflammation by reducing C. rodentium colonization, increasing colon length and levels of IL-10 and IL-22, decreasing IL-1β, IL-6, TNF-α, and IL-17 levels, inhibiting colonic crypt elongation and hyperplasia, and enhancing the intestinal mucosal barrier. The protective effects against intestinal bacterial infection are linked to enhanced clearance of C. rodentium and improvements in the intestinal mucosal barrier and C. rodentium-induced intestinal microbiota dysbiosis. Fecal microbiota transplantation experiments were conducted to evaluate the functional impact of microbiota induced by SFPs. The results suggest that intestinal microbiota modified by SFPs effectively countered C. rodentium infection. In addition, our study identified that miRNA-92a-3p is partially complementary to the 3'-UTR of the Notch1 gene, thereby repressing the Notch1-Hes1 signaling pathway and enhancing Muc2 secretion. Taken together, these findings reveal that SFPs protect mice from C. rodentium infection by activating the miR-92a-3p/Notch1-Hes1 regulatory axis driven by the intestinal microbiota, which stimulates Muc2 production to maintain intestinal barrier homeostasis.

An Overview of Early-Life Gut Microbiota Modulation Strategies.

The gut microbiota, or microbiome, is essential for human health. Early-life factors such as delivery mode, diet, and antibiotic use shape its composition, impacting both short- and long-term health outcomes. Dysbiosis, or alterations in the gut microbiota, is linked to conditions such as allergies, asthma, obesity, diabetes, inflammatory bowel disease, and necrotizing enterocolitis in preterm infants. This article reviews current strategies to influence the early-life gut microbiome and their potential health impacts. It also briefly summarizes guidelines on using biotics for gastrointestinal and allergic diseases in children. Key strategies include vaginal or fecal microbiota transplantation for cesarean-born infants, breastfeeding, and biotic-supplemented formulas. While vaginal microbial transfer and maternal fecal microbiota transplantation show short-term benefits, further research is needed to determine long-term safety and efficacy. Breast milk, rich in human milk oligosaccharides, promotes a healthy microbiota and offers protection against infections. Biotic-supplemented formulas can improve the gut microbiota in formula-fed infants and show clinical effects, though each biotic must be evaluated separately. Probiotics given as dietary supplements outside of infant formulas show promise for treating gastrointestinal disorders but require further investigation.

Inflammation-Induced Th17 Cells Synergize with the Inflammation-Trained Microbiota to Mediate Host Resiliency Against Intestinal Injury.

Inflammation can generate pathogenic Th17 cells and cause an inflammatory dysbiosis. In the context of inflammatory bowel disease (IBD), these inflammatory Th17 cells and dysbiotic microbiota may perpetuate injury to intestinal epithelial cells. However, many models of IBD like T-cell transfer colitis and IL-10-/- mice rely on the absence of regulatory pathways, so it is difficult to tell if inflammation can also induce protective Th17 cells. We subjected C57BL6, RAG1-/-, or JH-/- mice to systemic or gastrointestinal (GI) Citrobacter rodentium (Cr). Mice were then subjected to 2.5% dextran sodium sulfate (DSS) to cause epithelial injury. Fecal microbiota transfer was performed by bedding transfer and co-housing. Flow cytometry, qPCR, and histology were used to assess mucosal and systemic immune responses, cytokines, and tissue inflammation. 16s sequencing was used to assess gut bacterial taxonomy. Transient inflammation with GI but not systemic Cr was protective against subsequent intestinal injury. This was replicated with sequential DSS collectively indicating that transient inflammation provides tissue-specific protection. Inflammatory Th17 cells that have a tissue-resident memory (TRM) signature expanded in the intestine. Experiments with reconstituted RAG1-/-, JH-/- mice, and cell trafficking inhibitors showed that inflammation-induced Th17 cells were required for protection. Fecal microbiota transfer showed that the inflammation-trained microbiota was necessary for protection, likely by maintaining protective Th17 cells in situ. Inflammation can generate protective Th17 cells that synergize with the inflammation-trained microbiota to provide host resiliency against subsequent injury, indicating that inflammation-induced Th17 TRM T cells are heterogenous and contain protective subsets.

The combination of Clostridium butyricum and Akkermansia muciniphila mitigates DSS-induced colitis and attenuates colitis-associated tumorigenesis by modulating gut microbiota and reducing CD8+ T cells in mice.

Our study suggests that the combined administration of CB and AKK probiotics, as opposed to a single probiotic strain, holds considerable promise in preventing the advancement of IBD to CRC. This synergistic effect is attributed to the ability of this probiotic combination to more effectively modulate the gut microbiota, curb inflammatory reactions, bolster the efficacy of immunotherapeutic approaches, and optimize treatment results via fecal microbiota transplantation.

Gut Microbiome Modulation in Allergy Treatment: The Role of Fecal Microbiota Transplantation.

The prevalence of allergic diseases has been rising, paralleling lifestyle changes and environmental exposures that have altered human microbiome composition. This review article examines the intricate relationship between the gut microbiome and allergic diseases, emphasizing the potential of fecal microbiota transplantation as a promising novel treatment approach. It explains how reduced microbial exposure in modern societies contributes to immune dysregulation and the increasing incidence of allergies. The discussion also addresses immune homeostasis and its modulation by the gut microbiome, highlighting the shift from eubiosis to dysbiosis in allergic conditions. Furthermore, this article reviews existing studies and emerging research on the role of fecal microbiota transplantation in restoring microbial balance, providing insights into its mechanisms, efficacy, and safety.

The Metabolite Indole-3-Acetic Acid of Bacteroides Ovatus Improves Atherosclerosis by Restoring the Polarisation Balance of M1/M2 Macrophages and Inhibiting Inflammation.

Emerging research has highlighted the significant role of the gut microbiota in atherosclerosis (AS), with microbiota-targeted interventions offering promising therapeutic potential. A central component of this process is gut-derived metabolites, which play a crucial role in mediating the distal functioning of the microbiota. In this study, a comprehensive microbiome-metabolite analysis using fecal and serum samples from patients with atherosclerotic cardiovascular disease and volunteers with risk factors for coronary heart disease and culture histology is performed, and identified the core strain Bacteroides ovatus (B. ovatus). Fecal microbiota transplantation experiments further demonstrated that the gut microbiota significantly influences AS progression, with B. ovatus alone exerting effects comparable to volunteer feces from volunteers. Notably, B. ovatus alleviated AS primarily by restoring the intestinal barrier and enhancing bile acid metabolism, particularly through the production of indole-3-acetic acid (IAA), a tryptophan-derived metabolite. IAA inhibited the TLR4/MyD88/NF-κB pathway in M1 macrophages, promoted M2 macrophage polarisation, and restored the M1/M2 polarisation balance, ultimately reducing aortic inflammation. These findings clarify the mechanistic interplay between the gut microbiota and AS, providing the first evidence that B. ovatus, a second-generation probiotic, can improve bile acid metabolism and reduce inflammation, offering a theoretical foundation for future AS therapeutic applications involving this strain.

Delayed feeding disrupts diurnal oscillations in the gut microbiome of a neotropical bat in captivity.

Diurnal rhythms of the gut microbiota are emerging as an important yet often overlooked facet of microbial ecology. Feeding is thought to stimulate gut microbial rhythmicity, but this has not been explicitly tested. Moreover, the role of the gut environment is entirely unexplored, with rhythmic changes to gut pH rather than feeding per se possibly affecting gut microbial fluctuations. In this study, we experimentally manipulated the feeding schedule of captive lesser long-nosed bats, Leptonycteris yerbabuenae, to dissociate photic and feeding cues, and measured the fecal microbiota and gut pH every two hours. We detected strong diurnal rhythms in both microbial alpha- and beta diversity as well as in pH within the control group. However, a delay in feeding disrupted oscillations of gut microbial diversity and composition, but did not affect rhythms in gut pH. The oscillations of some genera, such as Streptococcus, which aid in metabolizing nutrients, shifted in accordance with the delayed feeding cue and were correlated with pH. For other bacterial genera, oscillations were disturbed and no connection to pH was found. Our findings suggest that the rhythmic proliferation of bacteria matches peak feeding times, providing evidence that diurnal rhythms of the gut microbiota likely evolved to optimize their metabolic support to the host's circadian phenotype.

Akkermansia muciniphila and its metabolite propionic acid maintains neuronal mitochondrial division and autophagy homeostasis during Alzheimer’s disease pathologic process via GPR41 and GPR43

BackgroundAlzheimer’s disease (AD) is a prevalent neurodegenerative disease (ND). In recent years, multiple clinical and animal studies have shown that mitochondrial dysfunction may be involved in the pathogenesis of AD. In addition, short-chain fatty acids (SCFA) produced by intestinal microbiota metabolism have been considered to be important factors affecting central nervous system (CNS) homeostasis. Among the main mediators of host-microbe interactions, volatile fatty acids play a crucial role. Nevertheless, the influence and pathways of microorganisms and their metabolites on Alzheimer’s disease (AD) remain uncertain.ResultsIn this study, we present distinctions in blood and fecal SCFA levels and microbiota composition between healthy individuals and those diagnosed with AD. We found that AD patients showed a decrease in the abundance of Akkermansia muciniphila and a decrease in propionic acid both in fecal and in blood. In order to further reveal the effects and the mechanisms of propionic acid on AD prevention, we systematically explored the effects of propionic acid administration on AD model mice and cultured hippocampal neuronal cells. Results showed that oral propionate supplementation ameliorated cognitive impairment in AD mice. Propionate downregulated mitochondrial fission protein (DRP1) via G-protein coupled receptor 41 (GPR41) and enhanced PINK1/PARKIN-mediated mitophagy via G-protein coupled receptor 43 (GPR43) in AD pathophysiology which contribute to maintaining mitochondrial homeostasis both in vivo and in vitro. Administered A. muciniphila to AD mice before disease onset showed improved cognition, mitochondrial division and mitophagy in AD mice.ConclusionsTaken together, our results demonstrate that A. muciniphila and its metabolite propionate protect against AD-like pathological events in AD mouse models by targeting mitochondrial homeostasis, making them promising therapeutic candidates for the prevention and treatment of AD.2Eefw-diaDYPDEcqvaR2iqVideo

Effects of dietary fiber on fecal microbiota of grower–finisher pig offspring from parents with divergent estimated breeding value for feed conversion ratio

Effects of dietary fiber on fecal microbiota of grower–finisher pig offspring from parents with divergent estimated breeding value for feed conversion ratio

Gut-Derived Ursodeoxycholic Acid from Saponins of Quinoa Regulated Colitis via Inhibiting the TLR4/NF-κB Pathway.

Alteration of the gut microbiota and its metabolites plays a key role in the development of inflammatory bowel disease (IBD). Here, we investigated the mechanism of saponins, a byproduct from quinoa (SQ) processing, in regulating IBD. SQ ameliorated gut microbiota dysbiosis revealed by 16S rRNA sequencing and improved colonic antioxidant activities and barrier integrity in dextran sulfate sodium (DSS)-treated mice. Broad-spectrum antibiotics further proved that the gut-protective effects of SQ were mediated by gut microbiota. Next, fecal microbiota transplantation (FMT) of SQ-induced gut microbiota/metabolites to inoculate DSS-treated mice alleviated colitis significantly. Untargeted metabolomics and lipidomics revealed that ursodeoxycholic acid (UDCA) was enriched as a microbial metabolite after SQ supplementation. UDCA was then found to attenuate DSS-induced colitis in vivo by targeting the TLR4/NF-κB pathway, which was also verified in a Caco-2 cell model treated with a TLR4 agonist/antagonist. Overall, our findings established that gut microbiota-UDCA-TLR4/NF-κB signaling plays a key role in mediating the protective effects of SQ.

From Clinical to Benchside: Lacticaseibacillus and Faecalibacterium Are Positively Associated With Muscle Health and Alleviate Age-Related Muscle Disorder.

Sarcopenia is an age-related muscle disorder that increases risks of adverse clinical outcomes, but its treatments are still limited. Gut microbiota is potentially associated with sarcopenia, and its role is still unclear. To investigate the role of gut microbiota in sarcopenia, we first compared gut microbiota and metabolites composition in old participants with or without sarcopenia. Fecal microbiota transplantation (FMT) from human donors to antibiotic-treated recipient mice was then performed. Specific probiotics and their mechanisms to treat aged mice were identified. Old people with sarcopenia had different microbial composition and metabolites, including Paraprevotella, Lachnospira, short-chain fatty acids, and purine. After FMT, mice receiving microbes from people with sarcopenia displayed lower muscle mass and strength compared with those receiving microbes from non-sarcopenic donors. Lacticaseibacillus rhamnosus (LR) and Faecalibacterium prausnitzii (FP) were positively related to muscle health of old people, and enhanced muscle mass and function of aged mice. Transcriptomics showed that genes related to tricarboxylic acid cycle (TCA) were enriched after treatments. Metabolic analysis showed increased substrates of TCA cycle in both LR and FP supernatants. Muscle mitochondria density, ATP content, NAD+/NADH, mitochondrial dynamics and biogenesis proteins, as well as colon tight junction proteins of aged mice were improved by both probiotics. LR and the combination of two probiotics also benefit intestinal immune health by reducing CD8+ IFNγ+ T cells. Gut microbiota dysbiosis is a pathogenesis of sarcopenia, and muscle-related probiotics could alleviate age-related muscle disorders mainly through mitochondria improvement. Further clinical translation is warranted.

Colorectal cancer in Lynch syndrome families: consequences of gene germline mutations and the gut microbiota

BackgroundLynch syndrome (LS)-associated colorectal cancer (CRC) always ascribes to pathogenic germline mutations in mismatch repair (MMR) genes. However, the penetrance of CRC varies among those with the same MMR gene mutation. Thus, we hypothesized that the gut microbiota is also involved in CRC development in LS families.MethodsThis prospective, observational study was performed from December 2020 to March 2023. We enrolled 72 individuals from 9 LS families across six provinces in China and employed 16S rRNA gene amplicon sequencing to analyze the fecal microbiota components among LS-related CRC patients (AS group), their spouses (BS group), mutation carriers without CRC (CS group), and non-mutation carriers (DS group) using alpha and beta diversity indices.ResultsThere were no apparent differences in age or gender among the four groups. Alpha and beta diversity indices exhibited no significant differences between the AS and BS groups, verifying the role of germline mutations in the occurrence of CRC in LS families. Beta diversity analysis exhibited significant differences between the AS and CS groups, revealing the importance of the gut microbiota for the occurrence of CRC in LS families. A greater difference (both alpha and beta diversity indices) was shown between the AS and DS groups, demonstrating the combined impact of the gut microbiota and genetic germline mutations on the occurrence of CRC in LS families. Compared with those in the CS and DS groups, we identified ten microbial genera enriched in the AS group, and one genus (Bacteroides) decreased in the AS group. Among the elevated genera in the AS group, Agathobacter, Coprococcus and Prevotellaceae_NK3B31_group were butyrate-producing genera.ConclusionThis study found the development of CRC in the LS families can be attributed to the combined effects of gene germline mutations as well as the gut microbiota and provided novel insights into the prevention and treatment of CRC in the LS families.

Potentially probiotic NPL 1334 strain of Enterococcus durans benefits rats with diet-induced hypercholesterolemia

PurposeTo study the potential of a candidate probiotic strain belonging to the Enterococcus durans species in alleviating hypercholesterolemia and improving the microbial milieu of rat gut.MethodsA previously isolated and characterized E. durans strain NPL 1334 was further screened in vitro for its bile salt hydrolyzation and cholesterol assimilation ability. An in vivo trial using diet-induced hypercholesterolemic rats was conducted to evaluate the effects of the administered test probiotic strain on the animal’s blood biochemical parameters such as total cholesterol (TC), high-density lipopolysaccharides (HDL), low-density lipopolysaccharides (LDL), triglycerides (TG), on body weight, oxidative stress markers, and its impact on intestinal and fecal microbiota as well as a histopathological examination of the test animal’s livers.ResultsE. durans strain showed good bile salt hydrolyzing ability and ample cholesterol assimilation in vitro. Probiotic-fed hypercholesterolemic rats showed significantly lowered cholesterol, triglyceride and LDL levels. The body weight of probiotic-fed rats was reduced as compared to the control. E. durans also stimulated the growth of beneficial LAB in the intestine of experimental rats and did not harm the liver of the experimental rats.ConclusionE. durans can be a natural therapeutic alternative to manage diet-induced hypercholesterolemia and may eventually enhance anti-cholesterolemic therapies.

Lactobacillus gasseri prevents ibrutinib-associated atrial fibrillation through butyrate.

Ibrutinib, a widely used anti-cancer drug, is known to significantly increase the susceptibility to atrial fibrillation (AF). While it is recognized that drugs can reshape the gut microbiota, influencing both therapeutic effectiveness and adverse events, the role of gut microbiota in ibrutinib-induced AF remains largely unexplored. Utilizing 16S rRNA gene sequencing, fecal microbiota transplantation, metabonomics, electrophysiological examination, and molecular biology methodologies, we sought to validate the hypothesis that gut microbiota dysbiosis promotes ibrutinib-associated AF and to elucidate the underlying mechanisms. We found that ibrutinib administration predisposes rats to AF. Interestingly, ibrutinib-associated microbial transplantation conferred increased susceptibility to AF in rats. Notably, ibrutinib induced a significantly decrease in the abundance of Lactobacillus gasseri (L. gasseri), and oral supplementation of L. gasseri or its metabolite, butyrate, effectively prevented rats from ibrutinib-induced AF. Mechanistically, butyrate inhibits the generation of reactive oxygen species (ROS), thereby ameliorating atrial structural remodeling. Furthermore, we demonstrated that ibrutinib inhibited the growth of L. gasseri by disrupting the intestinal barrier integrity. Collectively, our findings provide compelling experimental evidence supporting the potential efficacy of targeting gut microbes in preventing ibrutinib-associated AF, opening new avenues for therapeutic interventions.

The evolving landscape of live biotherapeutics in the treatment of Clostridioides difficile infection.

Clostridioides difficile (C. difficile) infection (CDI) is common after antibiotic exposure and presents significant morbidity, mortality and healthcare costs worldwide. The rising incidence of recurrent CDI, driven by hypervirulent strains, widespread antibiotic use and increased community transmission, has led to an urgent need for novel therapeutic strategies. Conventional antibiotic treatments, although effective, face limitations due to rising antibiotic resistance and high recurrence rates, which can reach up to 60% after multiple infections. This has prompted exploration of alternative therapies such as fecal microbiota-based therapies, including fecal microbiota transplantation (FMT) and live biotherapeutics (LBPs), which demonstrate superior efficacy in preventing recurrence. They are aimed at restoring the gut microbiota. Fecal microbiota, live-jslm and fecal microbiota spores, live-brpk have been approved by the U.S. Food and Drug Administration in individuals aged 18 years or older for recurrent CDI after standard antimicrobial treatment. They have demonstrated high efficacy and a favorable safety profile in clinical trials. Another LBP under study includes VE-303, which is not derived from human donor stool. This review provides a comprehensive overview of the current therapeutic landscape for CDI, including its epidemiology, pathophysiology, risk factors, diagnostic modalities and treatment strategies. The review delves into the emerging role of live biotherapeutics, with a particular focus on fecal microbiota-based therapies. We explore their development, mechanisms of action, clinical applications and potential to revolutionize CDI management.

Fecal microbiota transplantation combined with inulin promotes the development and function of early immune organs in chicks.

Modern management of chicks hinders the vertical transmission of intestinal microbiota, which is closely related to immunity. Inulin is a substrate that can be utilized by the microbiota. This study aimed to determine whether fecal microbiota transplantation (FMT) combined with inulin played a "1 + 1 > 2" role in enhancing the development and function of immune organs. Chicks were treated with 1 % inulin and/or fecal microbiota suspension on days 1-6. The growth performance, immune organ development, and immune indicators were evaluated on days 7, 14, and 21. Results showed that the combination of FMT and inulin significantly increased the immune organ index on day 7 and promoted the morphological structure and the expression of proliferating cell nuclear antigen (PCNA) in immune organs on days 7, 14, and 21. Each treatment increased the gene expression of interferon-gamma (IFN-γ), interleukin-4 (IL-4), interleukin-2 (IL-2), B cell-activating factor receptor (BAFFR), B cell linker (BLNK), C-X-C Motif Chemokine Ligand 12 (CXCL12), C-X-C Motif Chemokine Receptor 4 (CXCR4), and Biotin (Bu-1) to varying degrees. FMT combined with inulin significantly increased the expression of IgA-positive cells on days 7 and 14. In conclusion, the synergistic effect of FMT and inulin had beneficial impacts on the development and function of immune organs.