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.

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.

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.

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.

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.

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.

Bacillus subtilis, a probiotic bacterium with engineering potential, is widely used for the expression of exogenous proteins. In this study, we utilized the integrative plasmid pDG364 to integrate the hemagglutinin–neuraminidase (HN) gene from Newcastle disease virus (NDV) into the genome of the B. subtilis 168 model strain. We successfully constructed a recombinant B. subtilis strain (designated B. subtilis RH) that displays a truncated HN antigen fragment on the surface of its spores and further evaluated its immunogenic effects in mice. Using ELISA, we quantified the levels of IgG in serum and secretory IgA (sIgA) in intestinal contents. The results revealed that the recombinant B. subtilis RH elicited robust specific mucosal and humoral immune responses in mice. Furthermore, B. subtilis RH demonstrated potential mucosal immune adjuvant properties by fostering the development of immune organs and augmenting the number of lymphocytes in the small intestinal villi. Additionally, the strain significantly upregulated the relative expression of inflammatory cytokines such as IL-1β, IL-6, IL-10, TNF-α, and IFN-γ in the small intestinal mucosa. In conclusion, the B. subtilis RH strain developed in this study exhibits promising mucosal immunogenic effects. It holds potential as a candidate for an anti-NDV mucosal subunit vaccine and offers a novel preventive strategy for the poultry industry against this disease.

Duck viral hepatitis, primarily caused by duck hepatitis A virus type 1 (DHAV-1), poses a significant threat to the global duck industry. Bacillus subtilis is commonly utilized as a safe probiotic in the development of mucosal vaccines. In this study, a recombinant strain of B. subtilis, designated as B. subtilis RV, was constructed to display the DHAV-1 capsid protein VP1 on its spore surface using the outer coat protein B as an anchoring agent. The immunogenicity of this recombinant strain was evaluated in a mouse model through mixed feeding immunization. The results indicated that B. subtilis RV could elicit specific systemic and mucosal immune responses in mice, as evidenced by the high levels of serum IgG, intestinal secretory IgA, and potent virus-neutralizing antibodies produced. Furthermore, the recombinant strain significantly upregulated the expression levels of IL-2, IL-6, IL-10, TNF-α, and IFN-γ in the intestinal mucosa. Thus, the recombinant strain maintained the balance of the Th1/Th2 immune response and demonstrated an excellent mucosal immune adjuvant function. In summary, this study suggests that B. subtilis RV can be a novel alternative for effectively controlling DHAV-1 infection as a vaccine-based feed additive.

Cellulolytic bacteria with probiotic functions play a crucial role in promoting the intestinal health in herbivores. In this study, we aimed to correlate the 16S rRNA gene amplicon sequencing and fiber-degrading enzyme activity data from six different herbivore feces samples. By utilizing the separation and screening steps of probiotics, we targeted and screened high-efficiency fiber-degrading bacteria with probiotic functions. The animals included Maiwa Yak (MY), Holstein cow (CC), Tibetan sheep (TS), Southern Sichuan black goat (SG), Sichuan white rex rabbit (CR), and New Zealand white rabbit (ZR). The results showed that the enzymes associated with fiber degradation were higher in goat and sheep feces compared to cattle and rabbit’s feces. Correlation analysis revealed that Bacillus and Fibrobacter were positively correlated with five types of fiber-degrading related enzymes. Notably, the relative abundance of Bacillus in the feces of Tibetan sheep was significantly higher than that of other five herbivores. A strain TS5 with good cellulose decomposition ability from the feces of Tibetan sheep by Congored staining, filter paper decomposition test, and enzyme activity determination was isolated. The strain was identified as Bacillus velezensis by biological characteristics, biochemical analysis, and 16S rRNA gene sequencing. To test the probiotic properties of Bacillus velezensis TS5, we evaluated its tolerance to acid and bile salt, production of digestive enzymes, antioxidants, antibacterial activity, and adhesion ability. The results showed that the strain had good tolerance to pH 2.0 and 0.3% bile salts, as well as good potential to produce cellulase, protease, amylase, and lipase. This strain also had good antioxidant capacity and the ability to antagonistic Staphylococcus aureus BJ216, Salmonella SC06, Enterotoxigenic Escherichia coli CVCC196, and Escherichia coli ATCC25922. More importantly, the strain had good self-aggregation and Caco-2 cell adhesion rate. In addition, we tested the safety of Bacillus velezensis TS5 by hemolysis test, antimicrobial susceptibility test, and acute toxicity test in mice. The results showed that the strain had no hemolytic phenotype, did not develop resistance to 19 commonly used antibiotics, had no cytotoxicity to Caco-2, and did not have acute toxic harm to mice. In summary, this study targeted isolated and screened a strain of Bacillus velezensis TS5 with high fiber-degrading ability and probiotic potency. This strain can be used as a potential probiotic for feeding microbial preparations for ruminants.

Fluoride exposure is widespread worldwide and poses a significant threat to organisms, particularly to their gastrointestinal tracts. However, due to limited knowledge of the mechanism of fluoride induced intestinal injury, it has been challenging to develop an effective treatment. To address this issue, we used a series of molecular biology in vitro and in vivo experiments. NaF triggered m6A mediated ferroptosis to cause intestinal damage. Mechanistically, NaF exposure increased the m6A level of SLC7A11 mRNA, promoted YTHDF2 binding to m6A-modified SLC7A11 mRNA, drove the degradation of SLC7A11 mRNA, and led to a decrease in its protein expression, which eventually triggers ferroptosis. Moreover, NaF aggravated ferroptosis of the colon after antibiotics destroyed the composition of gut microbiota. 16 S rRNA sequencing and SPEC-OCCU plots, Zi-Pi relationships, and Spearman correlation coefficients verified that Lactobacillus murinus (ASV54, ASV58, and ASV82) plays a key role in the response to NaF-induced ferroptosis. Collectively, NaF-induced gut microbiota alteration mediates severe intestinal cell injury by inducing m6A modification-mediated ferroptosis. Our results highlight a key mechanism of the gut in response to NaF exposure and suggest a valuable theoretical basis for its prevention and treatment.

Brevibacillus laterosporus is a strain of probiotic bacteria that has been widely used in pest control, cash crop, and other production areas. However, few studies have been conducted on its use as a feed additive in animals. Therefore, the probiotic potential of B. laterosporus PBC01 was evaluated by characterizing hydrophobicity, auto-aggregation activity, bile salt and simulated gastrointestinal fluid tolerance, bienzymatic, and antibacterial activity. Antibiotic susceptibility, hemolysis assays, and supplemental feeding of mice were also performed to evaluate safety features. Our results showed that B. laterosporus PBC01 had moderate hydrophobicity, high auto-agglutination ability. Meanwhile, B. laterosporus PBC01 had good tolerance to bile salt and simulated gastrointestinal fluid. It had the ability to secrete protease, cellulase, and to inhibit various pathogens. In addition, B. laterosporus PBC01 was sensitive to many antibiotics, and did not produce hemolysin. In the safety assessment of mice, it did not cause any deaths, nor did it affect the cell components of blood, antioxidant capacity, and reproductive health. The study indicated the great probiotic characteristics and safety of B. laterosporus PBC01. This may provide a theoretical basis for the clinical application and development of probiotic-based feed additives.

Millions of residents in areas with high-fluoride drinking water supply ingest excessive levels of fluoride for long periods. This study investigated the mechanisms and impacts of lifelong exposure to naturally occurring moderate-high-fluoride drinking water on spatial-memory function by studying mice in controlled experiments. Spatial-memory deficits and disorders of hippocampal neuronal electrical activity were observed in mice exposed to 25-ppm or 50-ppm-fluoride drinking water for 56 weeks, but not in adult or old mice exposed to 50 ppm fluoride for 12 weeks. Ultrastructural analysis showed severely damaged hippocampal mitochondria, evidenced by reduced mitochondrial membrane potential and ATP content. Mitochondrial biogenesis was impaired in fluoride-exposed mice, manifesting as a significantly reduced mtDNA content, mtDNA-encoded subunits mtND6 and mtCO1, and respiratory complex activities. Fluoride reduced expression of Hsp22, a beneficial mediator of mitochondrial homeostasis, and decreased levels of signaling for the PGC-1 alpha/TFAM pathway-which regulates mitochondrial biogenesis-and the NF-kappa beta/STAT3 pathway-which regulates mitochondrial respiratory chain enzyme activity. Hippocampus-specific Hsp22-overexpression improved fluoride-induced spatial-memory deficits by activating the PGC-1 alpha/TFAM and STAT3 signaling pathways, while Hsp22-silencing aggravated the deficits by inhibiting both pathways. Downregulation of Hsp22 plays a vital role in fluoride-induced spatialmemory deficits by impacting mtDNA-encoding subsets and mitochondrial respiratory chain enzyme activity.

The giant panda is a unique vulnerable mammal in western China, and its main cause of death is digestive system diseases regardless of whether these animals are in the wild or in captivity. The relationship between the intestinal flora and the host exerts a significant impact on the nutrition and health of the giant pandas.

To evaluate the application effect of antimicrobial peptides Gal-13 (AMP Gal-13) instead of antibiotic feed additives, 90 7-day-old Ross 308 broilers were randomly divided into 3 groups. Group A was fed a basic diet as the control, and Groups B and C were supplemented with AMP Gal-13 (100 mg/kg and 200 mg/kg, respectively). After a 35-day feeding experiment, the weight and average daily gain (ADG) of the broilers in Group B were significantly higher than those of the broilers in Group A. The Enterococcus sp. and Escherichia coli counts in the ileum and cecum in Group A were significantly higher than those in Groups B and C, while the Lactic acid bacteria (LAB) and Bifidobacterium sp. counts were significantly lower. The amylase activity of the jejunum in Group B was significantly higher than that in Group A. The villus length (VL): crypt depth (CD) ratios of the jejunum and ileum in Group B were significantly higher than those in Group A. The glutathione peroxidase (GSH-Px) activities in the liver and serum in Groups B and C were significantly higher than those in Group A, while the malondialdehyde (MDA) activity was significantly lower. The titers of Newcastle disease virus (NDV)–specific antibodies were elevated significantly in Group B at the age of 42 days. Additionally, the weights of the spleen and thymus were significantly increased. The expression levels of Il-2, Il-6, Tgf-β4, Tnf-α, and Mif in the spleen in Groups B and C were significantly downregulated to different degrees; Il-4 expression in Group B was significantly upregulated, while Ifn-γ expression in Group C was significantly upregulated. The results suggested that adding AMP Gal-13 to the diet could improve intestinal digestion, the antioxidant capacity, and immune function, ultimately promoting the growth of broilers.