Tight Junction Protein Gene Research Articles

Phytase, 25-hydroxyvitamin D3 and cocci vaccination to broilers fed a calcium and phosphorus-reduced diet under Eimeria spp. challenge: effects on growth performance and intestinal health

A study evaluated the effects of phytase, 25-hydroxyvitamin D3 (25OHD), and cocci vaccination on broilers fed a diet reduced in calcium (Ca) and available phosphorus (avP) under Eimeria challenge. A total of 840 one-day-old male broilers were assigned to a 2 × 5 factorial arrangement based on cocci vaccination and dietary treatments. Half of the birds were vaccinated against coccidia on d 1, and all birds were orally challenged with Eimeria spp. (sporulated oocysts: 12,500 of E. maxima, 12,500 of E. tenella, and 62,500 of E. acervulina) on d 14. Dietary treatments included: 1) a nutrient adequate diet (PC); 2) a diet reduced by 0.2% in Ca and avP (NC); 3) NC plus 1,500 FTU/kg of phytase (NC+PHY); 4) NC plus 3,000 IU/kg of 25OHD (NC+25OHD); 5) NC with both PHY and 25OHD (NC+PHY+25OHD). SAS was used for data analysis, with significance set at P ≤ 0.05. Pre-infection growth performance was comparable across the treatments. However, vaccinated birds exhibited higher body weight (BW) and body weight gain (BWG) from 0 to 6 d postinoculation (DPI; P < 0.05). The NC diet reduced BWG from 6 to 12 DPI and increased the feed conversion ratio (FCR) during 6 to 12 DPI and the overall period (0-26 d) compared to the PC birds. In contrast, the supplementation with phytase, 25OHD, or both, returned BWG and FCR to levels seen with the PC diet (P < 0.01). Vaccinated birds also had reduced gut permeability at 5 DPI, increased intestinal villus height, and lower expression levels of the tight junction proteins junctional adhesion molecule 2 (JAM2) and occludin (OCLN) at 6 DPI (P < 0.05). Interestingly, the cocci vaccine resulted in lower E. acervulina but higher E. tenella oocyst shedding at 6 DPI (P < 0.01). Interaction effects were observed for duodenal lesion scores and ileal crypt depth at 6 DPI (P < 0.05). In conclusion, coccidial vaccination improved growth performance, decreased intestinal permeability, enhanced intestinal morphology, and modulated tight junction protein gene expression under Eimeria infection. Reducing dietary Ca and avP levels adversely affected growth performance and FI during the recovery phase, but these negative effects could be mitigated by supplementing with phytase or 25OHD.

Hyperuricemia drives intestinal barrier dysfunction by regulating gut microbiota

BackgroundHyperuricemia elevates gut permeability; however, the risk of its influence on the compromised intestinal barrier is poorly understood. AimsThis study was carried out, aiming to elucidate the orchestrators and disruptors of intestinal barrier in hyperuricemia. MethodsA mouse model of hyperuricemia was induced by administering adenine and oteracil potassium to mice. Allopurinol was used to decrease uric acid level, and antibiotics were administered to mice to deplete gut microbiota. Intestinal permeability was assessed using FITC-labeled dextran. Changes in gut microbial community were analyzed through 16S rRNA sequencing. IL-1β and TNF-α levels were quantified using ELISA. The expression of tight junction protein genes, TLR4, p65 and IL-1β, was determined with Q-PCR and Western blotting. ResultsAllopurinol treatment effectively reduced intestinal permeability and serum TNF-α levels. Antibiotic treatment alleviated but not abolished intestinal permeability. Uric acid alone was insufficient to increase Coca2 monolayer permeability. Allopurinol treatment altered microbial composition and suppressed opportunistic infections. Re-establishing hyperuricemia in a germfree mouse model protected mice from intestinal injury. Allopurinol and antibiotic treatments reduced TLR4 and IL-1β expressions, increased occludin and claudin-1 expressions but suppressed NF-ĸB p65 signaling. However, removing gut microbiota aggravated lipid metabolic dysfunction. ConclusionGut microbiota is a direct and specific cause for intestinal barrier dysfunction.

Dietary jack bean (Canavalia ensiformis L.) supplementation enhanced intestinal health by modulating intestinal integrity and immune responses of broiler chickens

This study investigated the influence of supplementing with jack beans on jejunal morphology, cecal short-chain fatty acids production, gene expression both of pro- and anti-inflammatory cytokines and tight junctions. Four treatment groups including 288 Indian River chicks that were one day old were randomized at random. While the treatment groups received jack bean supplementation at levels of 5 %, 10 %, and 15 %, the control group (0 %) was given a basal diet. For 11–35 days, each treatment consisted of 8 pens with 9 birds each. Supplementing with jack beans significantly enhanced butyrate production (P < 0.001), while at 10 % supplementation did not differ from control. Villus height (VH) and the ratio (VH:CD) were significantly (P < 0.001) increased by dietary treatments, while villus width (VW) and crypt depth (CD) were significantly (P < 0.05) decreased. TLR-3, TNF-a, and IL-6 were all significantly (P < 0.001) increased by dietary supplementation. However, at 15 %, TLR-3 and IL-6 were same with control. IL-18 was significantly (P < 0.05) decreased at 15 %. IL-10 decreased significantly (P < 0.001), but at 10 % same with control. At 5 and 10 %, IL-13 increased significantly (P < 0.001), whereas dietary treatments decreased at 15 % compared to control. Although ZO1 decreased significantly (P < 0.001) and OLCN increased significantly (P < 0.001), both ZO1 and OCLN were not significantly different from the control at 15 %. Dietary treatments significantly (P < 0.001) increased CLDN1 but did not differ from the control at 10 %. JAM2 decreased significantly (P < 0.001) with dietary treatments. In conclusion, jack bean supplementation may increase broiler chicken performance and intestinal health due to butyrate production. It may affect intestinal morphology and integrity by upregulating a tight junction protein gene. Jack beans also impacted jejunum immune responses and inflammatory cytokine gene expression.

Immunogenic effects of enamel matrix derivative on human alveolar ridge mucosa-derived vascular endothelial cells under lipopolysaccharide stimulation.

Early peri-implant disease detection remains difficult. Enamel matrix derivative (EMD), which is used for periodontal tissue regeneration, promotes leukocyte chemotactic factor and adhesion molecule expression in vascular endothelial cells. We hypothesized that stimulating vascular endothelial cells with EMD would induce an inflammatory response in the peri-implant mucosa, enabling early peri-implant infection detection. To verify this hypothesis, we assessed the intercellular adhesion between human alveolar ridge mucosa-derived vascular endothelial cells (ARMEC) stimulated with lipopolysaccharide (LPS) and EMD and human periodontal ligament-derived vascular endothelial cells (PDLEC). Leukocyte chemotactic factors and cell adhesion molecules were investigated and we established an experimental model of peri-implant disease by stimulating ARMEC (representing the peri-implant mucosa) with Porphyromonas gingivalis-derived LPS. ARMEC and PDLEC were obtained from patients (n = 6) who visited the Nippon Dental University Niigata Hospital. The cells were divided into four subcategories, each cultured with: LPS (1µg/mL), EMD (100µg/mL), LPS + EMD, and pure medium. Cell viability, leukocyte chemotactic factor (interleukin-8: IL-8), adhesion molecules (intercellular adhesion molecule-1: ICAM-1), tight junction protein gene expression (zonula occludens-1: ZO-1 and Occludin), and transendothelial electrical resistance (TEER) was then determined. LPS reduced ARMEC viability, whereas simultaneous stimulation with EMD improved it. LPS and EMD stimulation enhanced IL-8 and ICAM-1 gene expression, suppressed TEER, and decreased ZO-1 and Occludin expression levels compared to that with stimulation with LPS alone. EMD stimulates leukocyte migration, increase vascular permeability, and trigger an immune response in the peri-implant mucosa, thus facilitating the early detection and treatment of peri-implant disease.

Aberrant miR-29 is a predictive feature of severe phenotypes in pediatric Crohn's disease.

Crohn's disease (CD) is a chronic inflammatory gut disorder. Molecular mechanisms underlying the clinical heterogeneity of CD remain poorly understood. MicroRNAs (miRNAs) are important regulators of gut physiology, and several have been implicated in the pathogenesis of adult CD. However, there is a dearth of large-scale miRNA studies for pediatric CD. We hypothesized that specific miRNAs uniquely mark pediatric CD. We performed small RNA-Seq of patient-matched colon and ileum biopsies from treatment-naive pediatric patients with CD (n = 169) and a control cohort (n = 108). Comprehensive miRNA analysis revealed 58 miRNAs altered in pediatric CD. Notably, multinomial logistic regression analysis revealed that index levels of ileal miR-29 are strongly predictive of severe inflammation and stricturing. Transcriptomic analyses of transgenic mice overexpressing miR-29 show a significant reduction of the tight junction protein gene Pmp22 and classic Paneth cell markers. The dramatic loss of Paneth cells was confirmed by histologic assays. Moreover, we found that pediatric patients with CD with elevated miR-29 exhibit significantly lower Paneth cell counts, increased inflammation scores, and reduced levels of PMP22. These findings strongly indicate that miR-29 upregulation is a distinguishing feature of pediatric CD, highly predictive of severe phenotypes, and associated with inflammation and Paneth cell loss.

Effects of Dietary Aflatoxin B1 on Hybrid Grouper (Epinephelus fuscoguttatus ♀ × Epinephelus lanceolatus ♂) Growth, Intestinal Health, and Muscle Quality.

This study investigated the effects of varying doses of dietary aflatoxin B1 (AFB1) on the growth, intestinal health, and muscle quality of hybrid grouper. Four diets with varying AFB1 concentrations (0, 30, 445, and 2,230 μg kg-1) were used. Elevating AFB1 concentrations led to a decline in growth indexes, specifically the weight gain rate and the specific growth rate, although the survival rate remained unchanged. Morphological indicators showed a dose-dependent decline with AFB1 exposure. Intestinal MDA content and hindgut reactive oxygen species (ROS) levels increased, while antioxidant indexes and digestive enzymes decreased with higher AFB1 levels. AFB1 negatively influenced hindgut tight junction protein and antioxidant-related gene expression while promoting inflammation-related gene expression. The presence of AFB1 in the experiment led to a decrease in beneficial intestinal bacteria, such as Prevotella, and an increase in harmful intestinal bacteria, such as Prevotellaceae_NK3B31_group. Muscle lipid and unsaturated fatty acid content significantly decreased, while muscle protein and liver AFB1 content increased dramatically with higher AFB1 concentrations. AFB1 caused myofibrillar cleavage and myofilament damage, leading to increased spaces between muscle fibers. In conclusion, diets with AFB1 levels exceeding 30 μg kg-1 inhibited hybrid grouper growth, while levels surpassing 445 μg kg-1 resulted in hindgut ROS accumulation, inflammation, elevated intestinal permeability, reduced digestive enzyme activity, and compromised muscle quality.

Protective Effects of Niacin on Rumen Epithelial Cell Barrier Integrity in Heat-Stressed Beef Cattle.

The present study investigates the theoretical basis for maintaining normal physiological functions in heat-stressed beef cattle by exploring the effects of niacin supplementation on the permeability of the rumen epithelial cell barrier. Herein, 12 Jinjiang bulls with an average weight of approximately 400 ± 20.0 kg were randomly divided into three groups, thermoneutral (TN), heat-stressed (HS), and heat-stressed niacin-supplemented (HN) groups, with 4 bulls in each group. The experiment spanned 70 days, and the plasma concentrations of D-lactic acid, diamine oxidase (DAO), lipopolysaccharides (LPSs), and inflammatory cytokines were analyzed. Additionally, we assessed the gene expression of tight junction proteins to understand the effect of niacin supplementation on heat-stressed beef cattle. Our results revealed that heat stress significantly increased the D-lactic acid and LPS levels in beef cattle plasma on days 30 and 45 of the experiment (p < 0.05). Moreover, it led to a significant rise in DAO levels on day 30 (p < 0.05). Niacin supplementation significantly reduced the LPS levels on day 30 (p < 0.05). Heat stress significantly elevated the plasma concentrations of inflammatory cytokines interleukin-1β (IL-1β), IL-2, IL-6, and tumor necrosis factor-α (TNF-α) (p < 0.05), while reducing the IL-4 concentration (p < 0.05). However, niacin supplementation effectively mitigated the concentrations of these inflammatory factors by reducing IL-1β, IL-2, IL-6, and TNF-α concentrations and increasing IL-4 concentrations. The mRNA expressions of tight junction proteins zonula occluden-1 (ZO-1), claudin-1, claudin-4, and claudin-7 were significantly downregulated (p < 0.05) in the HS group compared to those in the TN group, and those of ZO-1 and occludin were significantly upregulated (p < 0.05) in the HN group compared to those in the HS group. Notably, no significant differences were observed in ruminal papillae length and width among the studied groups (p > 0.05). Our findings indicate that heat stress adversely impacted the tight junction structure of the rumen epithelium, leading to a significant reduction in the expression of tight junction protein mRNA. Consequently, heat stress impaired the rumen mucosal barrier function, resulting in increased intestinal permeability. The mechanism underlying this effect may be associated with the decreased expression of tight junction protein genes in the rumen epithelial cells. However, niacin supplementation mitigated the detrimental effects of heat stress on intestinal permeability in beef cattle and increased the expression of tight junction protein genes in the rumen epithelium, thereby effectively protecting the rumen barrier in heat-stressed beef cattle. These results highlight the potential of nicotinic acid as a protective agent against the negative impacts of heat stress on intestinal integrity in beef cattle.

Ageratina adenophora damages the rumen epithelium via inducing the expression of inflammatory factors in goats.

The aim of this experiment was to investigate the effects of Ageratina adenophora on the expression of epithelium tight junction proteins and inflammatory factors in the rumen of goats. Twelve goats were randomly divided into three groups. The first group was the blank control group (n = 3, C) which was fed normal diet. The second group was fistulas control group (n = 3, RFC), which was fitted with rumen fistulas, and fed normal diet. The third group was the A. adenophora test group (n = 6, AA), which was fitted with rumen fistulas and fed a mixture of 60% of normal diet and 40% of A. adenophora grass powder. The feeding experiment lasted for 90d, after which all goats were sacrificed and samples were collected from the rumen dorsal sac and ventral sac. The relative expression of mRNA of inflammatory factors in the rumen epithelium (tumor necrosis factor alpha [TNF-α], interferon gamma [IFN-γ], interleukin 1 beta [IL-1β], IL-2, IL-4, IL-6, and IL-10) and tight junction protein genes (occludin, claudin-1, and ZO-1) was measured by quantitative real-time fluorescence PCR. Expression of tight junction proteins in the rumen epithelium was measured by Western blot. A correlation was established between the expression of inflammatory factors and tight junction protein genes using Graph Pad Prism. The results showed that A. adenophora caused a significant increase in the mRNA expression levels of TNF-α, IFN-γ, IL-1β, IL-2, IL-6, and IL-10 in the rumen epithelial (P < 0.05 or P < 0.01). The expression of tight junction proteins at both gene and protein levels was significantly decreased (P < 0.05 or P < 0.01). Furthermore, the correlation analysis revealed that the changes in tight junction protein expression in the test group were closely related to the upregulation of the expression of inflammatory factors TNF-α and IFN-γ in rumen epithelial cells. In conclusion, the expression of inflammatory factors was increased and the expression of tight junction proteins was decreased in goats after feeding on A. adenophora, which caused some damage to the rumen epithelium.

Generation of Porcine Angiogenin 4-Expressing Pichia pastoris and Its Protection against Intestinal Inflammatory Injury.

Antimicrobial peptides have been extensively studied as potential alternatives to antibiotics. Porcine angiogenin 4 (pANG4) is a novel antimicrobial peptide in the angiogenin (ANG) family, which may have a regulatory effect on intestinal microflora. The object of present study is obtained pANG4 protein by heterologous expression, so as to explore the biological function of recombinant pANG4 (rpANG4). The pANG4 was expressed in Pichia pastoris (P. pastoris) and anti-inflammatory effects were investigated in intestinal porcine epithelial cell line-J2 (IPEC-J2) and mice. Purified rpANG4 had bacteriostatic activity and did not cause hemolysis or cytotoxicity at concentrations below 128 μg/mL. Purified rpANG4 increased the activity of IPEC-J2 and reduced apoptosis in vitro. rpANG4 reduced the pro-inflammatory gene expression and upregulated tight junction protein gene expression during inflammation. rpANG4 alleviated lipopolysaccharide (LPS)-induced liver and spleen damage, intestinal inflammation, jejunal apoptosis genes' expression, and improved immune function in an in vivo mice model. rpANG4 increased tight junction protein gene expression in jejunum, thereby improving the jejunum intestinal barrier function. In conclusion, rpANG4 had antibacterial activity, inhibited intestinal inflammation, improved intestinal barrier function, and alleviated liver and spleen damage. The current study contributes to the development of antibiotic substitutes and the improvement of animal health.

Effects of Vitamin A on Growth Performance, Antioxidants, Gut Inflammation, and Microbes in Weaned Piglets.

Piglet weaning is an important stage in production where changes in the environment and diet can cause problems such as intestinal inflammation and diarrhea. Vitamin A is an essential nutrient for human and animal growth and has immunomodulatory and inflammatory effects. A large body of literature has previously reported on the use of vitamin A in piglet production, so our experiment added different concentrations of vitamin A (0, 1100, 2200, 4400, 8800, and 17,600 IU/kg) to weaned piglet diets to study the effects of different doses on growth performance, intestinal barrier, inflammation, and flora in weaned piglets. We selected 4400 IU/kg as the optimum concentration of vitamin A in relation to average daily weight gain, feed intake, feed-to-weight ratio, and diarrhea rate, and subsequently tested the inflammatory factors, immunoglobulin content, antioxidant levels, and intestinal flora of weaned piglets. Results: We observed that the diarrhea rate of weaned piglets was significantly lower after the addition of 4400 IU/kg of vitamin A to the diet (p < 0.05). A control group and a 4400 IU/kg VA group were selected for subsequent experiments. We found that after the addition of vitamin A, the serum CAT level of weaned piglets increased significantly, the expression of Claudin-1 in the jejunum and ileum increased significantly, the expression of Occludin gene in the jejunum increased significantly, the expression of IL-5 and IL-10 in the ileum increased significantly (p < 0.05), and the expression of IL-4, IL-5, and IL-10 in the ileum increased significantly (p < 0.05). Meanwhile, in the colonic flora of vitamin A-added weaned piglets, the relative abundance of Actinobacteria and Erysipelotrichales decreased significantly, while the relative abundance of Bacteroidales increased significantly (p < 0.05). The results of this study indicated that vitamin A at 4400 IU/kg reduces diarrhea in weaned piglets by increasing antioxidant levels, increasing intestinal tight junction protein gene expression, and regulating colonic gut microbiota.

Role of microencapsulated Lactobacillus plantarum in alleviating intestinal inflammatory damage through promoting epithelial proliferation and differentiation in layer chicks.

The alleviating effects of Lactobacillus plantarum in microencapsulation (LPM) on lipopolysaccharide (LPS)-induced intestinal inflammatory injury were investigated in layer chicks. A total of 252 healthy Hy-Line Brown layer chicks were randomly divided into six groups. Birds were injected with saline or LPS except for the control, and the diets of birds subjected to LPS were supplemented with nothing, L. plantarum, LPM, and wall material of LPM, respectively. The viable counts of LPM reached 109 CFU/g, and the supplemental levels of L. plantarum, LPM, and WM were 0.02 g (109 CFU), 1.0 g, and 0.98 g, per kilogram feed, respectively. LPS administration caused intestinal damage in layer chicks, evidenced by increased proinflammatory factors accompanied by poor intestinal development and morphology (p < 0.05). LPM/LPS significantly increased body weight, small intestine weight and length, villus height, villus height/crypt depth, and mRNA relative expression of tight junction protein genes (p < 0.05) and performed better than free L. plantarum. These findings could be attributed to the significant increase in viable counts of L. plantarum in the small intestine (p < 0.05), as well as the enhanced levels of Actinobacteriota, Lactobacillaceae, and Lactobacillus in intestinal microbiota (p < 0.05). Such results could further significantly increase goblet and PCNA+ cell percentage (p < 0.05); the mRNA relative expressions of epithelial cell, fast-cycling stem cell, quiescent stem cell, endocrine cell, and Paneth cell; and goblet and proliferative cell marker genes, including E-cadherin, Lgr-5, Bmi-1, ChA, Lysozome, Mucin-2, and PCNA (p < 0.05). Furthermore, the mRNA relative expressions of key genes involved in epithelial cell proliferation, namely, c-Myc, Cyclin-1, Wnt-3, Lrp-5, and Olfm-4, exhibited significant upregulation compared with the LPS treatment, as well as the differentiating genes Notch-1 and Hes-1 (p < 0.05). To sum up, microencapsulated L. plantarum supplementation could alleviate intestinal injury in layer chicks induced by LPS by promoting the proliferation and differentiation of intestinal epithelial cells, which could be attributed to the increase in viable count of L. plantarum in the gut and optimization in intestinal microbial flora.

PSXIII-7 Effect of Dietary Supplementation of Lactobacillus Rhamnosus on Blood Profiles, Intestinal Morphology, Immune Responses, and Gene Expression of Tight Junction Proteins and Cytokines of Weaned Pigs

Abstract Dietary probiotics were used in the animal feeds because of the beneficial effect of improving gut health and immune responses as one of the potential alternatives to antibiotics. This study was conducted to evaluate the effect of dietary supplementation of Lactobacillus rhamnosus (ILDONG Bioscience Co. Ltd., Pyeongtaek, Republic of Korea) on blood profiles, small intestinal morphology, immune responses, and gene expression of tight junction proteins and inflammatory cytokines in ileum of weaned pigs. A total of 40 weaned pigs [6.21 ± 0.55 kg of initial body weight (BW); 28-day old] were allotted to 2 dietary treatments (4 pigs/pen; 5 replicates/treatment) in a randomized complete block design (block: initial BW) and fed for 4 weeks. Dietary treatments were 1) a commercial basal nursery diet (CON), and 2) CON + 0.02% Lactobacillus rhamnosus IDCC 3201 (PRO). The blood samples were collected from randomly selected 1 pig per pen on day 1, 7, 14, and 28 for blood profiles and immune responses. On the last day of experiment, the pigs were euthanized to collect duodenal, jejunal, and ileal segments for intestinal morphology and gene expression analysis. Intestinal morphology was measured villus height, width, area, crypt depth, villus height to crypt depth ratio, and number of goblet cells by hematoxylin and eosin staining method. The blood profiles were measured by using an automated hematology analyzer. The serum samples were used to measure concentrations of cytokines and cortisol by using porcine immunoassay ELISA kits. The gene expression of tight junction proteins and cytokines were measured by qRT-PCR. Data were analyzed by PROC GLM procedure of SAS. Experimental unit was a pen. Statistical model for blood profiles, immune responses, and intestinal morphology included dietary treatment as a main effect and initial BW as a covariate. The t-test was used for ileal gene expression. Pigs fed PRO had lower (P &amp;lt; 0.05) platelet level, crypt depth in duodenum and ileum, serum tumor necrosis factor-α (TNF-α), and interleukin-6 than those fed CON. The pigs fed PRO downregulated (P &amp;lt; 0.05) TNF-α and interleukin-8 genes compared with those fed CON, but upregulated (P &amp;lt; 0.05) claudin-1 and claudin-2 genes. In conclusion, probiotic Lactobacillus rhamnosus supplementation in nursery diet improved gut health through modulating blood profiles and immune responses, enhancing intestinal morphology, and regulating tight junction protein genes expression in ileum of weaned pigs.

Gut toxicity of polystyrene microplastics and polychlorinated biphenyls to Eisenia fetida: Single and co-exposure effects with a focus on links between gut bacteria and bacterial translocation stemming from gut barrier damage

Microplastics' (MPs) ability to sorb and transport polychlorinated biphenyls (PCBs) in soil ecosystems warrants significant attention. Although organisms mainly encounter pollutants through the gut, the combined pollution impact of MPs and PCBs on soil fauna gut toxicity remains incompletely understood. Consequently, this study examined the gut toxicity of polystyrene MPs (PS-MPs) and PCB126 on Eisenia fetida, emphasizing the links between gut bacteria and bacterial translocation instigated by gut barrier impairment. Our findings underscored that E. fetida could ingest PS-MPs, which mitigated the PCB126 accumulation in E. fetida by 9.43 %. Exposure to PCB126 inhibited the expression of gut tight junction (TJ) protein genes. Although the presence of PS-MPs attenuated this suppression, it didn't alleviate gut barrier damage and bacterial translocation in the co-exposure group. This group demonstrated a significantly increased level of gut bacterial load (BLT, ANOVA, p = 0.005 vs control group) and lipopolysaccharide-binding protein (LBP, ANOVA, all p < 0.001 vs control, PCB, and PS groups), both of which displayed significant positive correlations with antibacterial defense. Furthermore, exposure to PS-MPs and PCB126, particularly within the co-exposure group, results in a marked decline in the dispersal ability of gut bacteria. This leads to dysbiosis (Adonis, R2 = 0.294, p = 0.001), with remarkable signature taxa such as Janthinobacterium, Microbacterium and Pseudomonas, being implicated in gut barrier dysfunction. This research illuminates the mechanism of gut toxicity induced by PS-MPs and PCB126 combined pollution in earthworms, providing novel insights for the ecological risk assessment of soil.

The caecal microbiota promotes the acute inflammatory response and the loss of the intestinal barrier integrity during severe Eimeria tenella infection.

Coccidiosis, a disease caused by intestinal apicomplexan parasites Eimeria, is a threat to poultry production. Eimeria tenella is one of the most pathogenic species, frequently causing a high prevalence of opportunistic infections. The objective of this study is to investigate the role of the microbiota in the pathogenesis of severe Eimeria tenella infection. We have previously shown that microbiota can promote parasite development. To study the effect of the microbiota on the pathogenesis of this infection, we used an experimental condition (inoculum of 10 000 oocysts E. tenella INRAE) in which the parasite load is similar between germ-free and conventional broilers at 7 days post-infection (pi). Thirteen conventional and 24 germ-free chickens were infected. Among this latter group, 12 remained germ-free and 12 received a microbiota from conventional healthy chickens at 4 days pi. Caeca and spleens were collected at 7 days pi. Our results demonstrated caecal lesions and epithelium damage in conventional chickens at 7 days pi but not in germ-free infected chickens. Administration of conventional microbiota to germ-free chickens partially restored these deleterious effects. At day 7 pi, both infected conventional and germ-free chickens exhibited increased gene expression of inflammatory mediators, including IL15, IFNγ, TNFα and the anti-inflammatory mediator SOCS1, whereas the inflammatory mediators CXCLi2, CCL20, IL18, CSF1, NOS2, PTGS2, IL1β, IL6, the receptor CCR2, and the anti-inflammatory mediators TGFβ1 and IL10 were upregulated only in infected conventional chickens. Notably, the IL18, PTGS2 gene expression was significantly higher in the infected conventional group. Overall, the inflammatory response enhanced by the microbiota might be in part responsible for higher lesion scores. Epithelial tight junction protein gene expression analysis revealed a significant upregulation of CLDN1 with the infection and microbiota, indicating a potential loss of the intestinal barrier integrity. These observations imply that, during E. tenella infection, the caecal microbiota could trigger an acute inflammatory response, resulting in a loss of intestinal integrity. Increase in bacterial translocation can then lead to the likelihood of opportunistic infections. Hence, modulating the microbiota may offer a promising strategy for improving poultry gut health and limiting caecal coccidiosis.

Comprehensive analysis of the immunological differences in the intestinal barrier of improved grass carp and their parents

Disease-resistant grass carp (DR-GGC) was an improved grass carp developed by backcrossing gynogenetic grass carp (GGC, female) with grass carp (Ctenopharyngodon iIdella, GC, male), which had better disease resistance advantages than GC in aquaculture. However, little was known about the immune mechanism of disease resistance advantages of DR-GGC compared with GC. This study aimed to investigate the differences in molecular mechanisms of disease resistance among DR-GGC, GGC and GC by comparing intestinal histopathology, antioxidant activity in the liver and spleen, tight junction protein gene expression, intestinal microbiota structure, intestinal transcriptome and metabolomics following intestinal inflammation induced by Aeromonas hydrophila. The histopathological results showed that the intestinal villi of DR-GGC, GGC and GC were damaged with shedding and fusion, the intestinal damage of GC being the most severe. Tight junction protein gene expression in the intestine and antioxidant enzyme activity in the liver and spleen were significantly higher in DR-GGC than in GC (P < 0.05), whereas serum creatinine (CRE) and plasma free hemoglobin (FHB) were significantly below that in GC (P < 0.05). Meanwhile, the transcriptome results showed that the differentially expressed genes (DEGs) were significantly enriched in immune response-related pathways in DR-GGC and GGC compared with GC (P < 0.05). The DEGs were also enriched in cellular and molecular processes in DR-GGC and GC compared with GGC (P < 0.05). The metabolomics results revealed lipid and oxidative metabolism-related differential metabolites (DMs) among the three grass carp groups. Furthermore, twenty amino acids and their metabolites were up-regulated in DR-GGC compared with GC, including aspartic acid, arginine, ornithine and others, and cloud significantly reduces intestinal inflammation by regulating the immune and oxidative responses. And the combined analysis of the transcriptome and metabolome revealed that the DEGs and DMs in these pathways were significantly correlated and regulated. Additionally, the intestinal microbiota analysis showed that DR-GGC had an increased abundance of probiotic Fusobacteriota at the phylum level and Cetobacterium at the genus level. Conversely, GC had an increased abundance of pathogenic Bacteroidetes at the phylum level and Aeromonas at the genus level. In conclusion, this study comprehensively confirmed the greater disease resistance of DR-GGC and further elucidated the potential molecular mechanism of better intestinal immune barrier resistance than that of GC, which is of significant value for the development of the GC.

Disruption of the intestinal barrier by avermectin in carp involves oxidative stress and apoptosis and leads to intestinal inflammation

Avermectin (AVM) is a widely used insecticide. Due to its sensitive toxicity to aquatic organisms, the toxicology of AVM on fish intestines remains unclear. Here, we established a 96 h AVM acute toxicity model to explore the effects of AVM on the intestinal tract of carp. The 96 h LC50 of carps exposed to AVM was 24.04 μg/L, 12.02 μg/L was selected as the high-dose group and 3.005 μg/L was selected as the low-dose group. After 96 h of exposure, intestinal tissues were collected and subsequently analyzed for histopathology, the activities of antioxidant oxidases (CAT, SOD, GSH-Px), and the expression of mRNA associated with oxidative stress, inflammation, and apoptosis. Our study showed that AVM exposure caused intestinal damage in carp, decreased the expression of the tight junction protein gene, activated oxidative stress, induced apoptosis, and induced intestinal inflammation in carp. Therefore, we demonstrated that AVM exposure compromised the integrity of the intestinal barrier in carp, activated oxidative stress, induced endogenous apoptosis, and induced intestinal inflammatory responses. These results indicate that AVM, as a drug-sensitive to aquatic organisms, has a much more complex toxic effect on the fish intestinal tract, which provides a new perspective for studying the toxicology of AVM on the fish intestinal tract.

Study of the biosynthesis and functionality of polyphosphate in Bifidobacterium longum KABP042

Polyphosphate (poly-P) biosynthesis in bacteria has been linked to many physiological processes and has been characterized as an interesting functional molecule involved in intestinal homeostasis. We determined the capacity for poly-P production of 18 probiotic strains mainly belonging to Bifidobacterium and former Lactobacillus genera, showing that poly-P synthesis varied widely between strains and is dependent on the availability of phosphate and the growth phase. Bifidobacteria were especially capable of poly-P synthesis and poly-P kinase (ppk) genes were identified in their genomes together with a repertoire of genes involved in phosphate transport and metabolism. In Bifidobacterium longum KABP042, the strain we found with highest poly-P production, variations in ppk expression were linked to growth conditions and presence of phosphate in the medium. Moreover, the strain produced poly-P in presence of breast milk and lacto-N-tetraose increased the amount of poly-P synthesized. Compared to KABP042 supernatants low in poly-P, exposure of Caco-2 cells to KABP042 supernatants rich in poly-P resulted in decreased epithelial permeability and increased barrier resistance, induction of epithelial protecting factors such as HSP27 and enhanced expression of tight junction protein genes. These results highlight the role of bifidobacteria-derived poly-P as a strain-dependent functional factor acting on epithelial integrity.

Protective effects of polydatin on ileum injury in mice exposed to aflatoxin B1

Aflatoxin B1 (AFB1) is an extremely hazardous food/feed pollutant, posing a serious threat to health of human and animals. Particularly, exposure to AFB1 provokes enterocytes oxidative stress and inflammation, which lead to intestinal damage. Polydatin (PD), a stilbenoid glucoside, is known to possess antioxidant and anti-inflammatory properties and is being investigated for use in various disorders. The present study was intended at investigating the protective efficacy of polydatin against AFB1-induced ileum damage in mice. Kunming male mice received oral gavage of AFB1 (300 μg/kg body weight/day) and PD (100 mg/kg body weight/day) for 18 days. The results showed that mice exposed to AFB1 exhibited the impaired morphology, the suppressed disaccharidase activities, the down-regulated mRNA expressions of tight junction protein genes, oxidative stress, inflammation and the up-regulated mRNA expressions of genes related to mitophagy in the ileum, whereas PD treatment reversed the AFB1-induced disruption of ileal structure, digestion, barrier function, redox and immune status. The findings of the present study suggested that PD may have a potential benefit in preventing AFB1-induced ileum damage.

Effects of Dietary Supplementation of Antimicrobial Peptide on Growth Performance, Serum Biochemistry and Intestinal Health in Broilers

Background: The study was undertaken to determine the efficiency of supplementation of antimicrobial peptide on growth performance, serum biochemistry, intestinal morphology, antioxidant status and gene expression of cytokines and tight junction proteins in broiler chicks as an alternative to antibiotic growth promoters that impart residues in broiler meat. Methods: The FCR was calculated by dividing the respective feed intake of chicks by weight gain during the respective period. Two broiler chicks were randomly selected from each replicate based on the average body weight of the corresponding replicate. After sacrifice, blood for serum and sections of small intestine were collected for the assessment of intestinal morphology, antioxidant activity measurement and gene expression of cytokines and tight junction proteins. Result: The results revealed that supplementation of antimicrobial peptide significantly improved the overall weight gain of broiler chicks compared to the NC. There was a significant increase in the activities of intestinal superoxide dismutase and glutathione peroxidase in the antimicrobial peptide supplemented group. AMP significantly modulates the gene expression of intestinal cytokines (IL-17A, IFN-α, IFN-γ and IL-10) and tight junction protein genes. These results indicate that antimicrobial peptide supplementation had beneficial effects on growth performance and intestinal health in broilers.

Caffeic acid improves intestinal barrier functions by regulating colonic bacteria and tight junction protein expression and alleviating inflammation in weaning piglets

The experiment investigated the effect of caffeic acid on bacteria, short-chain fatty acids (SCFA), and the expression of tight junction protein and inflammation related genes in the colon of weaning piglets. Thirty-six weaning piglets were allocated to three treatment groups, which were fed with a basal diet, a basal diet supplemented with 250 mg/kg or 500 mg/kg caffeic acid for 28 days. The results showed that caffeic acid treatment increased the contents of acetate acid, propionate acid and total SCFA. Moreover, real-time quantitative PCR showed that the number of Bifidobacterium (p < 0.05) and Lactobacillus (p < 0.05) were increased and the number of Escherichia coli (p < 0.05) was decreased by caffeic acid in colonic mucosa. Real-time quantitative PCR also showed that the mRNA levels of zonula occludens-1 (p < 0.01), claudin-1 (p < 0.01), occludin (p < 0.01), mucin 1 (MUC1) (p < 0.01), MUC2 (p < 0.01), interleukin 4 (IL-4) (p < 0.01) and IL-10 (p < 0.05) were increased, while the mRNA expression levels of histone deacetylases (p < 0.01), IL-1 (p < 0.01), IL-6 (p < 0.01) and tumor necrosis factor-α (TNF-α) (p < 0.01) were decreased, by caffeic acid in colonic mucosa. These results suggested that caffeic acid could improve intestinal barrier function in weaned pigs, which might be mediated by regulating colonic bacteria and tight junction protein expression and alleviating inflammation.