Abstract In areas with high fluoride concentrations in drinking water, residents may consume excessive fluoride, which may increase the risk of renal impairment. Although accumulating evidence suggests that probiotics may exert renoprotective effects, support for probiotic interventions against fluoride-associated renal injury remains limited, and the effects appear to be strain dependent. In a prolonged exposure model, mice received sodium fluoride in drinking water (25 or 50 ppm) for 56 weeks, after which renal function was assessed and metagenomic profiling was performed. Mice exposed to varying fluoride concentrations developed renal injury, and the relative abundance of Bifidobacterium animalis was significantly correlated with markers of renal function. A short-term fluoride-exposure model (sodium fluoride, 24 mg/kg/day for 8 weeks, by gavage) was used to evaluate the renal protective effect of Bifidobacterium animalis GY007. Supplementation with GY007 significantly reduced renal injury markers, including β2-microglobulin (β2-MG) and lipocalin 2 (LCN2). GY007 reduced pro-inflammatory cytokines interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), increased anti-inflammatory interleukin-10 (IL-10), and alleviated oxidative stress. Transmission electron microscopy (TEM) analysis indicated that GY007 improved mitochondrial morphology in damaged renal tissue. Further analyses showed that GY007 improved mitochondrial membrane potential, attenuated the upregulation of dynamin-related protein 1 (Drp1) and fission 1 (Fis1), and normalized altered mitochondrial DNA (mtDNA) copy number. The mRNA levels of mtDNA-encoded genes (mtND3, mtCO2, and mtcyb) and the nuclear-encoded gene Sdhb were altered. Kidney metabolomic analysis revealed metabolic alterations associated with GY007 supplementation in fluoride-exposed mice, identifying eight significantly altered metabolites. This study provides evidence supporting the development of probiotic interventions to mitigate fluoride-associated renal injury in settings with elevated fluoride concentrations in drinking water.

Exposure to fluoride is strongly associated with impaired intestinal function. Probiotics are widely regarded as an effective strategy to maintain microbial homeostasis and to mitigate the progression of fluoride-induced intestinal injury. This study aimed to evaluate the measurable protective effects of the probiotic strain Bifidobacterium animalis subsp. animalis (B. animalis subsp. animalis) GY007 in reversing high fluoride-induced ileal injury. The results showed that GY007 (1 × 109 CFU/mL, once/daily) attenuated intestinal barrier disruption and alleviated ileal mucosal abnormalities in mice receiving fluoride (24 mg/kg) by gavage for eight consecutive weeks. GY007 attenuated elevated oxidative stress and modulated the inflammatory response associated with the TLR9/NF-κb/IRF7 signaling pathway. Microbiome and metabolomic analyses showed that GY007 reversed the dysregulation of the ileal microbial community structure and metabolite profiles. Spearman’s rank correlation analysis further supported a regulatory role for Bifidobacterium in this protective process and identified three key functional metabolites meriting further investigation: isocytosine (ISO), 7α,24S-dihydroxy-3-oxocholest-4-en-26-oic acid (OIC-7α), and sinapinic acid (SIA). Our findings demonstrate that GY007 protects against fluoride-induced ileal injury and elucidate the associated changes in the intestinal microbial community and metabolite profiles. This study provides new evidence clarifying the restorative effect of the probiotic GY007 on the ileum under environmental fluoride exposure, offering an integrative perspective on the interaction between microorganisms and their host.

Fluoride pollution—whether of geological or anthropogenic origin—disrupts gut microbiota–host homeostasis and compromises the intestinal barrier. We established an acute high-fluoride mouse model via intragastric NaF, integrating metagenomics, metabolomics, and molecular biological techniques to clarify the underlying mechanism of enhanced intestinal permeability caused by fluoride exposure in vivo. Mechanistically, high fluoride exposure activates the RhoA/ROCK signaling pathway, increases the level of phosphorylated myosin light chain (p-MLC), induces filamentous actin (F-actin) rearrangement, and disrupts the apical junctional complex (AJC)—characterized by downregulated expression or abnormal localization of AJC-related proteins (ZO-1, Claudin-1, β-catenin, Occludin). It also alters the morphology of intestinal epithelial cells, ultimately increasing ileal permeability. At the microbiota level, high fluoride disrupted the ileal microbiota; specifically, at the species level, Bifidobacterium sp. SO1 and Schaalia turicensis were identified as the key species with high specificity and high occupancy under fluoride exposure. Lactobacillus and Akkermansia were abnormally enriched in the intestines of mice exposed to fluoride. Metabolomic analysis revealed that high fluoride exposure enriched multiple pathways including linoleic acid metabolism and sphingolipid metabolism, altering the levels of 11 cytoskeleton-related metabolites. Correlation analysis confirmed that Bifidobacterium sp. SO1 and Schaalia turicensis were strongly correlated with damage phenotypes, pathway molecules, and metabolites, indicating that these two strains are closely associated with cytoskeleton changes and increased intestinal permeability under high fluoride exposure. Collectively, our findings reveal that gut microbiota drive fluoride-induced intestinal barrier dysfunction through the “microbiota–RhoA/ROCK–cytoskeleton” axis, highlighting a novel host–microbe interaction mechanism underlying environmental toxin–mediated gut injury.

AIMS:Porcine reproductive and respiratory syndrome virus (PRRSV) remains a major threat to swine production, while safe and practical mucosal immunization strategies with broad reactivity are still limited. This study aimed to develop a spore surface-display mucosal immunomodulatory platform by presenting a multiepitope PRRSV antigen on Bacillus subtilis spores and to assess its ability to stimulate mucosal and systemic immune responses. METHODS AND RESULTS:An applied spore surface-display platform was constructed by engineering Bacillus subtilis 168 spores to present a tandem fusion antigen (ER) comprising conserved linear B- and T-cell epitopes derived from PRRSV ORF1b, GP5, M, and N proteins. Recombinant spores were administered orally to BALB/c mice as a proof-of-concept model, and mucosal and systemic immunogenicity was evaluated in comparison with control spores and a commercial inactivated vaccine. B. subtilis BE significantly increased ER-specific intestinal secretory IgA and serum IgG, and PRRSV (R98)-specific neutralising activity was detectable in the ER group. BE administration also promoted a Th1-skewed mucosal cytokine profile (increased IFN-α, TNF-α, and IFN-γ with reduced IL-6) and increased the proportion of CD8⁺ T cells in mesenteric lymph nodes. CONCLUSIONS:Surface display of a conserved multiepitope PRRSV antigen on B. subtilis spores stimulated coordinated mucosal, humoral, and cellular immune responses in mice. These findings support further exploration of spore-based microbial delivery systems as a potential mucosal immunisation adjuvant and immunomodulatory approach for PRRSV; however, the use of BALB/c mice represents a non-natural host model, and protective efficacy remains to be validated in target animals and challenge studies.

Enterotoxigenic Escherichia coli (ETEC) causes severe intestinal infections in animals and threatens public health under the One Health framework. Most conventional studies focus on acute short-term ETEC infection, while natural persistent colonization oftern induces chronic intestinal mucosal compensatory remodeling in hosts. This study evaluated the protective effects of giant panda-derived Weissella confusa BSP201703 against chronic ETEC-induced intestinal damage using a giant panda fecal microbiota-associated (GPF) mouse model. Seventy-two Kunming mice were divided into six groups: blank control (C1), GPF control (C2), ETEC control (C3), and three W. confusa BSP201703 groups at low (1.0 × 107 cfu/mL, W1), medium (1.0 × 108 cfu/mL, W2), and high (1.0 × 109 cfu/mL, W3) doses. Mice were first subjected to continuous ETEC challenge for 5 days to establish stable chronic intestinal injury, followed by a subsequent 5-day intervention with probiotic or sterile PBS for repairing existing damage. Growth performance, histopathology, serum D-lactate, SIgA, tight junction genes (ZO-1, Occludin, Claudin-1), and gut microbiota were analyzed. Histomorphologically, the chronic ETEC challenge induced compensatory increases in ileal villus height and crypt depth, which differed from typical acute necrotic atrophy. W. confusa BSP201703 mitigated ETEC-induced damage, reduced serum D-lactate (p < 0.05), increased SIgA, and upregulated tight junctions (p < 0.05). Microbial results demonstrated that medium-dose W2 maximized microbial diversity, while W1/W3 selectively enriched beneficial Bacteroidetes, Clostridium cluster IV, and Clostridium cluster XIVa taxa, confirming that moderate doses yielded optimal protection. In conclusion, W. confusa BSP201703 relieves ETEC injury by enhancing intestinal barrier function and regulating gut microbiota, highlighting its potential as a wildlife probiotic for One Health applications.

This experiment investigated the effects of dietary supplementation with GutPlus® Virsorb probiotic on piglets infected with porcine epidemic diarrhea virus (PEDV). Seventy-two Duroc × Landrace × Yorkshire weaned piglets (21 days of age, 5.51 ± 0.44 kg) were randomly divided into: the CON1 group (negative control, basal diet), the CON2 group (positive control, basal diet), and the GutPlus® Virsorb group (basal diet + 500 g/t GutPlus® Virsorb). At 28 days of age, piglets in the CON2 and GutPlus® Virsorb groups received 40 mL PEDV (8.58 × 108 copies/mL) orally, while the CON1 group received an equivalent volume of sterile saline. The experiment lasted until 60 days of age. Dietary supplementation with GutPlus® Virsorb ameliorated the decrease in the average daily feed intake (ADFI) and the average daily gain (ADG) caused by PEDV infection. Compared with the CON2 group, GutPlus® Virsorb increased jejunal mucosa GPX and decreased jejunal mucosa MDA. Additionally, GutPlus® Virsorb decreased the mRNA expressions of IFN-β, TNF-α, and IL-6 in the jejunal mucosa. Compared to the CON2 group, GutPlus® Virsorb increased relative abundances of Lactobacillus, Prevotella, Akkermansia, and Butyricicoccus_A, while the relative abundance of Clostridium_P and Clostridium_T was reduced. In addition, GutPlus® Virsorb significantly increased the relative quantitative values of cis-cyclo (leucyl-tyrosyl), oxyphenbutazone, callicarpic acid B, and tilisolol. In conclusion, GutPlus® Virsorb improved the growth performance of PEDV-infected piglets, alleviated inflammation and intestinal damage by improving immunity, reduced PEDV copy number, increased antioxidant capacity, and improved gut microbiota structure and metabolite properties, showing a good protective effect against PEDV infection.

High-altitude environments (> 2500 m) with low oxygen, low pressure, variable climate, large diurnal temperature differences, and high solar and ultraviolet radiation are risky to human health. Mice’s intestinal microbiota changes at high altitude may affect cognition via the gut–brain axis. Short-term high-altitude exposure may have positive effects on organisms. This study explores if short-term high-altitude exposure can protect working memory from restraint stress (RS) and the role of intestinal microbiota in this process. Forty-eight C57BL/6 mice aged eight weeks were divided into four groups: the Control group, RS group (S group), high altitude exposed group (HA group), and high-altitude exposed with RS group (HA-S group). High altitude was simulated via exposure to a low-pressure oxygen chamber at a simulated altitude of 3500–4000 m for 14 days. RS was simulated from days 22–29 and followed by the novel object recognition test to assess working memory. Blood for serum, prefrontal cortex, ileal sections for molecular analysis, and intestinal contents for 16S rRNA sequencing were collected. Compared to control mice that were not exposed to high altitude and did not experience RS, mice that were also exposed to high altitude and experienced restraint stress had significantly greater working memory deficits, whereas mice exposed only to high altitude did not show significant differences in working memory performance. Different gut microbial community structures were observed in these groups, with high altitude-exposed mice exhibiting higher α-diversity. In addition, the difference in β-diversity between restraint stress and high altitude exposed mice was significantly higher, indicating significant differences in microbial community composition. The major bacterial phyla identified were Firmicutes, Bacteroidetes, Proteobacteria, and Actinobacteria, with Lactobacillus being more abundant in the restraint stress group, while Bifidobacterium and Muribaculum were relatively more abundant in the high-altitude exposed with restraint stress group, but the relative abundance of Lactobacillus was lower. Short-term high-altitude exposure might possibly protect working memory function by modulating intestinal function through the microbiota–gut–brain axis, with Lactobacillus perhaps contributing to alleviate working memory dysfunction induced by stress. This study may enhance our understanding of the microbiota-gut-brain axis in high-altitude environments and could offer new preventive and therapeutic insights for high-altitude-related health issues, possibly benefiting workers and explorers in such environments.

Rationale: Chronic exposure to high-fluoride drinking water impairs intestinal structure and function, potentially damaging extraluminal tissues via the gut-organ axis. However, how lifelong exposure to naturally occurring moderate-to-high-fluoride water affects intestinal cells and their underlying mechanisms remain unclear. Methods: Single-cell RNA sequencing identified cellular heterogeneity and candidate risk genes in the mouse ileum after 56 weeks of 50-ppm fluoride exposure. Cellchart was employed to analyze fluoride-altered cell communication patterns, and gut bacterial richness was ablated using broad-spectrum antibiotics to validate high fluoride-disrupted intercellular signaling pathways. Results: Fluoride exposure disrupted enterocyte trans-differentiation, affected metabolic health by restricting nutrient absorption, and activated antibacterial activity in enterocytes at the villus base. Downregulation of genes associated with rapid goblet-cell emptying and transmembrane mucin 3 in goblet cell impairs mucus and glycocalyx formation. Antimicrobial peptides, lectins, and lysozymes were reduced in fluoride-exposed Paneth and goblet cells. Fluorescence in situ hybridization demonstrated bacterial invasion of the epithelium following mucus barrier damage. Immunologically, fluoride-exposed T cells exhibit high scores for apoptosis, cell cycle suppression, inflammation, and high gut-homing gene expression. Fluoride exposure promoted somatic hypermutation and affinity selection in B-lineage cells while expanding plasma cells with high developmental potential. Ligand-receptor analysis revealed that activated enterocytes presented antigens to T cells via the MHC-II L-R signaling pathway, triggering downstream responses such as upregulating proinflammatory factors and cytotoxic molecules, and remodeling B-lineage cells. Broad-spectrum antibiotics depleted gut microbiota, reducing fluoride-induced gut microbial overgrowth and suppressing MHCII signaling in enterocytes and T/B cell activation-thereby decreasing proinflammatory cytokines and immunoglobulins. Conclusions: High-fluoride exposure disrupts the intestinal mucus barrier and gut microbiota homeostasis, leading to bacterial invasion of the epithelium that activates MHC-II signaling in absorptive enterocytes. Upregulated MHC-II signaling triggers intestinal immune cell activation and inflammation. These results reveal new intercellular interactions and communication hubs in intestinal cells under fluoride exposure.

This study evaluated Brevibacillus laterosporus (PBC01) on growth performance, immunity and intestinal health of male Lohmann Brown laying chickens. A total of 144 7-day-old chickens were randomly assigned to four dietary treatments: a basal diet supplemented with 0

Duck hepatitis A virus type 1 (DHAV-1) demonstrates extremely high lethality in 3-week-old ducklings, while causing subclinical infections in adult ducks with latent pathogenicity. Our previous research developed a vaccine-functional probiotic preparation targeting DHAV-1-recombinant Bacillus subtilis RV. In the present study, we conducted a 28-day oral immunization trial in Cherry Valley ducks to evaluate the immunoprotective effects and probiotic functions of this engineered strain. Results showed that B. subtilis RV induced humoral and mucosal immune responses in ducklings, producing high levels of specific IgG and intestinal secretory IgA, demonstrating immune-enhancing capabilities. During DHAV-1 challenge tests, it significantly reduced viral loads in various organ tissues. Additionally, B. subtilis RV improved the growth performance and antioxidant capacity of ducklings. Furthermore, this engineered probiotic enhanced intestinal health by improving intestinal structure, increasing tight junction protein expression, and modulating gut microbiota composition. This study evaluates a novel vaccine-functional probiotic preparation, providing a new strategy for DHAV-1 prevention and control.

IntroductionHigh-altitude environments have significant effects on brain function, particularly a decline in cognitive function, due to insufficient oxygen supply. The microbiome-gut-brain axis (MGBA) plays an important role in regulating cognitive function, but its specific mechanism of action in high-altitude environments is unclear. Therefore, the aim of this study was to investigate whether the probiotic Lactobacillus johnsonii HL79 could alleviate high altitude-induced cognitive dysfunction in mice by modulating the gut microbiota.Methods and resultsSixty C57BL/6 mice aged 8 weeks were randomly divided into four groups: control, high altitude exposure (HA), HL79-treated (P), and high altitude exposure plus HL79-treated (HAP). the HA and HAP groups were exposed to a low-pressure oxygen chamber at a simulated altitude of 3,500–4,000 m for 20 weeks, while the Control and P groups were maintained at the normal barometric pressure level. Probiotic HL79 was given daily by gavage in the P and HAP groups, while saline gavage was given daily in the other two groups. The cognitive functions of the mice were assessed by new object recognition test and elevated plus maze test. The results showed that HL79 treatment significantly improved the working memory abilities of high altitude exposed mice. In addition, HL79 treatment improved antioxidant capacity, decreased malondialdehyde (MDA) content, and increased superoxide dismutase (SOD) and catalase (CAT) activities in serum and whole brain tissue. Gut microbiota analysis showed that HL79 was able to modulate the structure of gut microbiota and increase the relative abundance of beneficial flora in high altitude environment.ConclusionLactobacillus johnsonii HL79 significantly ameliorated cognitive dysfunction in high altitude-exposed mice by modulating the gut microbiota and antioxidant capacity, further confirming the important role of MGBA in high altitude environment.

Edwardsiella tarda (E. tarda) is a common pathogen in aquaculture, with the capacity to infect a diverse range of farmed fish and result in significant economic losses. In this study, two recombinant Bacillus subtilis (B. subtilis) strains were constructed using the spore coat protein Y as the fusion gene sequence. Recombinant B. subtilis Et1 displays OmpA, the major surface antigen of E. tarda, on its spore surface, and recombinant B. subtilis Et2 displays fusion proteins of OmpA with the mucosal adjuvant cholera toxin B subunit (CTB). Adult female mice were randomly divided into four groups. Groups B, C, and D were fed a diet containing wild-type B. subtilis 168, recombinant B. subtilis Et1, and B. subtilis Et2 spores (2.0 x 10(6) CFU/g), respectively. Group A served as the blank control group and was fed a basal diet alone. On days 14, 28, and 42 of the feeding period, serum and small intestinal contents were collected from each group of mice, and the levels of anti-OmpA specific serum IgG and intestinal mucosa secretory IgA (sIgA) antibodies were measured by ELISA. The remaining mice were then subjected to a challenge test against E. tarda on day 42. Adult male zebrafish were grouped and immunized according to the same methods described above. On day 45 of feeding, the serum-specific IgM antibody levels of the zebrafish in each group were quantified via ELISA, and a challenge test was conducted to ascertain the cumulative mortality rate. The results demonstrated that the oral administration of recombinant spores led to the production of high levels of specific IgG and sIgA antibodies in mice. Additionally, recombinant strains induced the production of specific serum IgM antibodies in zebrafish, with significant differences (P < 0.05) when compared with group A and B. The antibody levels induced by the fusion of mucosal adjuvant with antigen (group D) were found to be significantly higher (P < 0.05) than those observed in the single antigen (group C). In the challenge study, RPS values in mice immunized with recombinant B. subtilis Et1 and Et2 were 50 % and 60 %, respectively. Moreover, the RPS values of the two zebrafish groups were as high as 72.9 % and 85.4 %, respectively. The current study successfully exhibited OmpA or OmpA-CTB fusion proteins on the surface of B. subtilis spores. Furthermore, we evaluated the immunization effects of these recombinant strains by oral immunization in mouse and zebrafish models. This provides a novel approach to the development of oral vaccines for aquaculture.

The intestine is particularly susceptible to oxidative damage given its extensive exposure to environmental toxins, dietary components, and microbial metabolites, which leads to various gastrointestinal and systemic diseases. There is an urgent need for effective and safe therapies to maintain intestinal redox balance. This study aimed to explore whether the pig-native strain Lactobacillus johnsonii JJB3, known for its potential in mitigating oxidative stress, can prevent intestinal oxidative stress and elucidate its underlying mechanisms. Our study found that L. johnsonii JJB3 supernatant (sJJB3) effectively ameliorated hydrogen peroxide (H2O2)-induced oxidative stress in intestinal porcine epithelial cell line-J2 (IPEC-J2), manifested by reduced levels of reactive oxygen species (ROS) and increased levels of catalase and glutathione. RNA sequencing revealed that the mitophagy pathway plays a crucial role in this protective effect. Specifically, sJJB3 treatment further enhanced H2O2-induced upregulation of BNIP3L and LC3B at both mRNA and protein levels, promoting mitophagy. These findings were validated in a mouse model of diquat (DQ)-induced intestinal oxidative stress. sJJB3 supplementation reversed DQ-induced oxidative damage, especially in the jejunum, and increased BNIP3L and LC3B expression. Transmission electron microscopy further confirmed that sJJB3 preserved mitochondrial ultrastructure and supported effective mitophagy. Additionally, 16S rRNA sequencing showed that sJJB3 improved gut microbiota composition. These results provide a new theoretical foundation for the application of sJJB3 in mitigating oxidative stress-related intestinal injury.

Hyperuricemia (HUA) is a metabolic disease characterized by elevated serum uric acid, which is closely related to the gut microbiota. Probiotics have great potential in improving HUA. The purpose of this study was to evaluate the effect and mechanism of probiotic product (SQK) containing Heyndrickxia coagulans TBC169 on HUA rats. Forty SD rats (6 weeks old, 200 ± 20 g) were randomly divided into four groups (Ctrl group, HUA group, SQK1 group, and SQK2 group) of 10 rats each. Rats were given potassium oxonate (100 mg potassium oxonate/100 g BW/day) for 12 weeks to establish HUA model and simultaneously administered with sterile saline (HUA group) or different dose of SQK (SQK1 group, 20.48 mg SQK/100 g BW/day; SQK2 group, 40.95 mg SQK/100 g BW/day) throughout the 12 weeks. The results showed that SQK could degrade uric acid precursors and inhibit the xanthine oxidase (XOD) activity in vitro. Oral supplementation of SQK can reverse the increase of serum uric acid, the increase of the liver and serum XOD activity, and the decrease of ABCG2 expression in the ileum induced by HUA. In addition, SQK could restore the changes in α and β diversity of the ileal microbiota and prevent the increase in pathogenic Helicobacter and Staphylococcus caused by HUA. 16S rRNA sequencing and correlation analysis showed that the chondroitin sulfate (CS) degradation pathway of the gut microbiota played a key role in the prevention of HUA in the SQK group. These findings suggest that SQK may improve HUA by reducing uric acid synthesis and increasing uric acid excretion and provide a basis for its development into a probiotic product to improve HUA.

Enterotoxigenic Escherichia coli (ETEC) is a prevalent intestinal pathogen that significantly impacts both human and animal health. G83, isolated from giant panda feces, has demonstrated notable probiotic properties. In this study, C57BL/6 J mice were randomly divided into Control, ETEC, and G83 groups. Experimental included monitoring body weight, assessing fecal occult blood, histopathological examination of ileal tissues, and quantification of antioxidant markers (SOD, T-AOC, MDA) in ileal tissues. Furthermore, real-time quantitative PCR was utilized to determine mRNA expression levels of inflammatory cytokines (TNF-α, IL-17, IL-10), tight junction proteins (Claudin, ZO-1, Occludin), mucin (Muc2), and lysozyme (Lyz-1). Transcriptomic bioinformatics analysis and 16S rRNA sequencing were integrated to characterize host gene expression profiles and gut microbial compositional dynamics, respectively. The results revealed that G83 alleviated ETEC-induced weight loss, reduced fecal occult blood, and mitigated ileal structural injuries. Additionally, G83 significantly enhanced intestinal antioxidant capacity by increasing T-AOC and SOD levels. Mechanistically, G83 downregulated pro-inflammatory cytokines TNF-α and IL-17 and the levels of Muc2 and Lyz1, while upregulating the expression of tight junction proteins ZO-1, Claudin, and Occludin. Transcriptomic analysis suggests that ETEC triggers inflammasome activation and initiates inflammatory responses by significantly upregulating Aim2. Conversely, G83 exerts protective effects by modulating the immune regulatory network—specifically, by significantly downregulating C3 expression to activate the complement system and participating in mucosal immune remodeling. Enrichment analysis reveals that G83 alleviates ETEC-induced intestinal inflammation primarily by inhibiting the NF-κB pathway and enhancing the intestinal IgA immune network. Additionally, 16S rRNA analysis indicates that G83 may improve ETEC-induced alterations in microbial community structure by increasing the abundance of beneficial bacteria (e.g., Lactobacillus), thereby further ameliorating impairment of intestinal microbial barrier function in mice. These findings provide a scientific basis for using G83 to ameliorate ETEC-mediated intestinal inflammation.

This experiment investigated the effects of dietary supplementation with probiotic GutPlus® Virsorb (GV) on systemic antioxidant capacity and gut health in piglets infected with Porcine Epidemic Diarrhea Virus (PEDV). A total of 72 crossbred (Duroc × Landrace × Yorkshire) weaned piglets (21 days of age, 5.51 ± 0.44 kg) were randomly divided into: the CON1 group (negative control, basal diet), the CON2 group (positive control, basal diet), and the GV group (basal diet + 500 g/t GV). At 28 days of age, piglets in the CON2 and GV groups were challenged with oral inoculation with 40 mL PEDV (8.58 × 108 copies/mL), whereas the CON1 group received an equivalent volume of DMEM medium. The experiment lasted until 60 days of age. Probiotic GV significantly enhanced systemic antioxidant capacity, as evidenced by elevated serum SOD activity and reduced MDA levels. Concurrently, GV effectively promoted gut health by alleviating ileal damage (improved villus architecture), reducing viral load and shedding, and reshaping the gut ecosystem. The latter included enriching beneficial bacteria (Lactobacillus, Limosilactobacillus, Phascolarctobacterium_A), reducing potentially harmful bacteria (Desulfovibrio_R), and increasing beneficial metabolites such as indolelactic acid and pinocembrin. In summary, probiotic GV supplementation alleviates PEDV infection in piglets by concurrently boosting host antioxidant defenses and restoring multiple facets of gut health. These findings support the potential of GV as a dietary strategy to enhance host resilience specifically against PEDV infection in weaned piglets.

High fluoride exposure was widely demonstrated to be related with brain memory impairment. Since the absorption of F- enters the body mainly through the gastrointestinal tract, studying the effects of excessive intake of fluoride on brain memory function in various gut microbiome states might have profound implications for the prevention of fluorosis because growing evidence revealed the significance of the “microbiota-gut-brain” axis (MGBA). In the present study, we aimed to illustrate the potential mechanism of gut microbiota on high fluoride exposure-induced hippocampal lesions and spatial memory dysfunction in mice by the various intestinal microecological environments, which were constructed by antibiotic treatment. Mice fed with normal (CG1 and Exp1 groups) or sodium-fluoride (CG2 and Exp2 groups; 24 mg/kg sodium fluoride per mouse) by gavage administration with or without antibiotic treatments, a combination of metronidazole (1 g/L) and ciprofloxacin (0.2 g/L) in drinking water. Mice gavaged with excessive sodium fluoride alone exhibited reduced weight gain, hippocampal tissue damages, spatial memory levels dysfunction, impaired intestinal permeability, decreased inflammatory cytokines expression and antioxidant capability in the hippocampal and ileal tissues. In contrast, antibiotic intervention significantly reversed these high fluoride exposure-induced hippocampal and ileal changes.16S rRNA high throughput sequencing found that ileal microbiota were dominated by abundant taxa, which is conducive to constructing microbial interaction networks and module communities, and identifying keystone species targeted by high fluoride exposure compared with colonic microbiome. In addition, the microbial community composition and assembly mechanism of ileal microbiome under the effects of antibiotics were suitable for revealing the characteristics of high fluoride environment. In the later analysis, Lactobacillus, Staphylococcus, Muribaculaceae and Robinsoniella were considered as the keystone species targeted by high fluoride-exposed mice based on the analysis of network node properties and niche overlap of ileal microbes. Spearman rank correlation demonstrated that these keystone species had significant effects on hippocampal memory levels and intestinal health, as well as microbial communities functions. Compared to previous researches, this study further revealed intestinal microbial coummunity mediated the underlying mechanism through antibiotic treatment against high fluoride-induce hippocampal spatial memory impairment.

Based on the microbiota-gut-brain axis (MGBA) hypothesis, probiotics play an increasingly important role in treating various psychiatric disorders. Schizophrenia (SCZ) is a common mental disease with a complex pathogenesis and is challenging to treat. Although studies have elucidated the mechanisms associated with the interactions between the microbiota-gut-brain axis and SCZ, few have specifically used probiotics as a therapeutic intervention for SCZ. Accordingly, the current study determines whether L. johnsonii YH1136 effectively prevents SCZ-like behavior in mice and identifies the associated key microbes and metabolites. An SCZ mouse model was established by intraperitoneal injection of MK-801; L. johnsonii YH1136 was administered via oral gavage. L. johnsonii YH1136 significantly improves abnormal behaviors, including psychomotor hyperactivity and sociability and alleviates aberrant enzyme expression associated with tryptophan metabolism in SCZ mice. Additionally, L. johnsonii YH1136 upregulates hippocampal brain-derived neurotrophic factor (BDNF) levels while downregulating tryptophan 2,3-dioxygenase (TDO2), indoleamine-pyrrole 2,3-dioxygenase 1 (IDO1), kynurenine aminotransferase 1 (KAT1). Subsequent 16S rRNA sequencing of intestinal contents suggests that L. johnsonii YH1136 modulates the gut flora structure and composition by increasing the relative abundance of Lactobacillus and decreasing Dubosiella in SCZ mice. N-acetylneuraminic acid and hypoxanthine are the key serum metabolites mediating the interaction between the MGBA and SCZ. These results partially reveal the mechanism underlying the effects of L. johnsonii YH1136 on SCZ-like behavior in mice, supporting the development of therapeutic L. johnsonii probiotic formulations against SCZ.

Plateau environment represents a common terrestrial characterized by multistress conditions including hypobaric hypoxia, low temperature, and intense radiation, yet sustain over 100 million permanent or transient inhabitants. While this extreme environment exerts profound impacts on cerebral architecture and gut microbiota homeostasis, precipitating cognitive deficits and microbiome-derived intestinal pathologies, the mechanistic interplay between plateau environment adaptation and microbial dynamics remains contentious. Here, we employ a microbiota-gut-brain axis framework to investigate whether probiotic intervention can ameliorate hippocampal impairments induced by simulated plateau environment exposure (3500-4000 m) in mice. Through simulated plateau environment exposure experiments, we revealed that extreme high-altitude conditions induced hippocampal memory dysfunction in mice, exacerbated oxidative stress damage in hippocampal tissues, and altered synaptic plasticity-related biomarkers including CREB transcription factor, BDNF protein levels, and electrophysiological power spectra. Administration of HL79 alleviated these burdens, including memory dysfunction and tissue damage, though complete reversal was not achieved. Combined hippocampal transcriptomic analyses suggested that HL79's beneficial effects primarily involved modulation of lipid-related gene expression in the hippocampus, consistent with prior reports of plateau environmental impacts on gene expression. Serum metabolomic results further reinforced this inference that differential metabolites regulated by HL79 are mainly enriched in bile secretion, taurine and hypotaurine metabolism, linoleic acid metabolism, and PPAR signaling pathways, though the precise regulatory mechanisms require further elucidation. This research provides a novel microbiota-gut-brain axis-based regulatory strategy for adaptation to extreme plateau environments and offers new evidence for understanding the relationship between gut microbiota and plateau environment adaptation at high elevations.

Porcine reproductive and respiratory syndrome virus (PRRSV), a single-stranded RNA virus, is a highly contagious pathogen that causes severe reproductive and respiratory disorders in pigs, leading to significant economic losses in the swine industry worldwide. However, current commercial vaccines provide only limited protection against circulating PRRSV strains, highlighting the urgent need for novel vaccine strategies. B. Bacillus subtilis , a well-characterized probiotic, has emerged as a promising platform for mucosal vaccine delivery due to its safety profile and ability to induce robust immune responses. In this study, we screened B cell and T cell linear epitopes from PRRSV-ORF1b, GP5, M, and N proteins to construct a recombinant tandem antigen (ER), which was displayed on the surface of B. subtilis 168 spores. The resulting recombinant strain, designated B. subtilis BE, was evaluated for immunogenicity in mice via oral administration. The results showed that Oral immunization with B. subtilis BE significantly elevated antigen-specific secretory IgA levels in intestinal contents and IgG levels in serum, indicating potent mucosal and systemic humoral responses. Moreover, B. subtilis BE induced measurable neutralizing antibody titers and enhanced cellular immunity, as evidenced by increased frequencies of CD3+ and CD8+ T cells in mesenteric lymph nodes and upregulation of IFN-α, TNF-α , and IFN-γ expression in intestinal tissues. Collectively, these findings demonstrate that B. subtilis BE elicits both humoral and cellular immune responses and may serve as a novel oral vaccine candidate against PRRSV, offering a promising alternative for controlling the ongoing epidemic. ### Competing Interest Statement The authors have declared no competing interest.