Enterococcus faeciumHDRsEf1 elevates the intestinal barrier defense against enterotoxigenicEscherichia coliand regulates occludin expression via activation of TLR-2 and PI3K signalling pathways

Short-term supplementation with uncoated and encapsulated Enterococcus faecium affected growth performance, gut microbiome and intestinal barrier integrity in broiler chickens

Enterococcus faecium (E. faecium) is an alternative to antibiotics, while the probiotic effect of short-term application in mature broiler chickens remains unclear. In the current study, 48 Arbor Acres male broilers were chosen to investigate the effects of E. faecium on growth performance, the gut microbiome and intestinal health during the finishing period. Forty-eight birds were randomly allocated to 4 treatment groups that were fed a corn-soybean meal basal diet (Con), a basal diet supplemented with 1 g/kg amoxicillin (ABX), 5×106 CFU/g encapsulated E. faecium (cEF), or 5×106 CFU/g uncoated E. faecium (EF) from d 33 to 42. The results showed that 10 d of antibiotic treatment decreased the growth performance of the broilers (P < 0.05). The feed conversion ratio of the cEF and EF groups were lower than that of the Con group by 0.13 and 0.07, respectively (P > 0.05). The abundance of viable ileal and cecal E. faecium in the cEF group was greater than that in the EF group (P < 0.05), and both groups were markedly greater than those in the Con and ABX groups (P < 0.05). The ABX treatment decreased the Shannon and Chao1 indices of the cecal microbiota, while the dietary E. faecium treatment resulted in significant differences in the β diversity of the ileal and cecal microbiota (P < 0.05). Mantel correlation revealed that the ileal microbiota at the genus level was significantly correlated with the growth performance of broilers, with Lactobacillus, Bacillus and Escherichia-Shigella showing positive and strong correlations (P < 0.05). In the ileum, the crypt depth was lower in the cEF group than in the Con group, but the villi height-to-crypt depth ratio was greater in the cEF group than in the other groups (P = 0.037). However, the expression of the ZO-2 and Occludin genes was downregulated in the E. faecium-fed birds (P < 0.05). In the cecum, the acetate, butyrate and total SCFA levels were greater in the EF group (P < 0.05), while the propionate, isobutyrate and isovalerate levels were lower in the ABX group (P < 0.05). In summary, 10 d of dietary supplementation with E. faecium markedly increased colonization in mature broilers and potentially improved growth performance by modulating the ileal microbiota. Encapsulation techniques could enable a slow release of E. faecium in the intestine, thereby reducing the negative impacts of rapid expansion of E. faecium on the intestinal epithelium.

Enterococcus faecium HDRsEf1 Promotes Systemic Th1 Responses and Enhances Resistance to SalmonellaTyphimurium Infection

The gut microbiota is known to regulate the immune system and thereby influence susceptibility to infection. In this study, we observed that the administration of Enterococcus faecium HDRsEf1 (HDRsEf1) led to an improvement in the development of the immune system. This was evidenced by an increase in both the spleen index and the area of spleen white pulp. Specifically, the proportion of T helper (Th) 1 cells and the production of IFN-γ and IL-12 were significantly increased in the spleens of mice treated with HDRsEf1. In agreement with the in vivo results, we found that Th1-related cytokines, including IFN-γ and IL-12p70, were strongly induced in splenocytes treated with HDRsEf1. In addition, Th1 cell activation and high-level secretion of IL-12p70 were also confirmed by coculture of CD4+ T cells with bone marrow-derived dendritic cells treated with HDRsEf1. Moreover, the employment of HDRsEf1 was identified to augment resilience against systemic infection provoked by S. Typhimurium and stimulate the expression of the genes for TNFα and iNOS in the initial stage of infection, signifying that reinforced Th1 cells and IL-12 might activate macrophages for antibacterial safeguards. In summary, our study suggests that HDRsEf1 could act as an effective immunobiotic functional agent, promoting systemic Th1 immunological responses and priming defenses against infection.

Usnea improves high-fat diet- and vitamin D3-induced atherosclerosis in rats by remodeling intestinal flora homeostasis

Background: Usnea has various pharmacological properties, including anti-inflammatory, antitumor, antioxidant, antiviral, and cardiovasculoprotective effects. Aim of the study: To investigate the potential mechanisms underlying the anti-atherosclerosis (AS) activity of Usnea ethanol extract (UEE) via the regulation of intestinal flora. Materials and Methods: The chemical composition of UEE was determined using ultra-performance liquid chromatography with quadrupole exactive orbitrap mass spectrometry (UPLC-Q-EOMS). Thirty-six male Sprague-Dawley rats were divided into six groups. A high-fat diet and intraperitoneal vitamin D3 injections were used to establish a rat model of AS. After 4 weeks of treatment with UEE, hematoxylin-eosin staining was performed to evaluate the pathomorphology of the aorta, liver, and colon. The composition and diversity of the rat intestinal flora were determined using high-throughput 16S rRNA sequencing. Enzyme-linked immunosorbent assays were used to measure the levels of plasma trimethylamine oxide (TMAO), serum bile acid (BA), total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), lipopolysaccharide (LPS), tumor necrosis factor-alpha (TNF-α), and interleukin-6 (IL-6). The protein expression of cholesterol 7α-hydroxylase (CYP7A1) and flavin monooxygenase 3 (FMO3) in the liver and zonula occludens-1 (ZO-1) and occludin in colon tissue was detected via western blotting. Results: Forty-four compounds were identified in UEE. In the rat model of AS, UEE significantly prevented calcium deposition; decreased the serum levels of TC, TG, LDL-C, LPS, TNF-α, and IL-6; and increased the serum level of HDL-C. Additionally, all UEE dosages decreased the relative abundance of Verrucomicrobiota while increased that of Bacteroidetes. FMO3 protein expression and TMAO levels decreased, whereas CYP7A1 protein expression and BA levels increased. The absorption of intestinal-derived LPS was minimized. Furthermore, the protein expression of ZO-1 and occludin was upregulated. Conclusion: UEE ameliorated AS. The underlying mechanism was the reversal of imbalances in the intestinal flora by Usnea, thereby inhibiting calcium deposition, abnormal lipid metabolism, and inflammatory response.

Cytoprotective Effects of Lactobacilli on Mouse Epithelial Cells during Salmonella Infection

Treatment of common pathogens, such as Salmonella species, Escherichia coli, Staphylococcus aureus, etc., is a big challenge for a practitioner. Antibiotics’ side effects during their application for the treatment of infectious diseases should not be underestimated as they have many issues, such as the transfer of antibiotics-resistant genes, dysbiosis, and antibiotic-resistant strains, which is the main hurdle in the eradication of diseases. To avoid these antibiotics complications, in modern countries, the interest of using probiotics in feed supplementation to promote health and prevent or treat intestinal infectious diseases has been increasing. The purpose of the present study was to evaluate the probiotic potential of three Lactobacilli strains isolated from clinically healthy dogs for their further utilization as a dietary supplement for dogs to avoid pathogenic and antibiotic complication. After 16SrRNA sequencing, in vitro tests were conducted to assess the survival potential of Lactobacilli under simulated gastrointestinal conditions and adhesion ability to the MODE-K cell line, effects on epithelial barrier function, anti-inflammatory activities, effects on host defensin peptides (beta-defensin 3), and inhibitory effects on common pathogens. Lactobacilli showed considerable potential to survive in simulated gastrointestinal environmental conditions, low pH, and high bile salt concentrations along with good adhesion properties with MODE-K cells. Pathogenic bacterial growth and their adhesion to MODE-K cells were significantly inhibited by Lactobacilli. Real-time PCR analyses further demonstrated that the L. acidophilus strain AR1 and AR3 inhibit Salmonella-induced proinflammatory cytokine (IL-6, IL-8, IL-1β) production and reinforce the expression of tight junction protein (occludin). None of the strains induce mRNA expression of beta-defensin 3 in MODE-K cells. Based on the in vitro results, the L. acidophilus strain AR1 has the potential to be supplemented in canine feed. However, further in vivo studies investigating health-promoting effects are awaited.

The probiotic potential of Lactobacillus plantarum strain RW1 isolated from canine faeces

AIM

To evaluation the probiotic potential of Lactobacillus plantarum strain RW1 isolated from healthy dogs for its further utilization as a dietary supplement for dogs.

METHODS AND RESULTS

This study aimed to evaluate the probiotic potential of L. plantarum strain RW1 isolated from canine faeces. After confirming by conventional and then by 16S rRNA sequencing, the identified strain RW1 was in vitro screened for its survivability in simulated gastrointestinal conditions, low pH, bile salts and adhesion to gut epithelial tissues, growth inhibitory effects on common pathogens and anti-inflammatory potential by measuring the mRNA expression level of IL-6, IL-8, IL-1ꞵ in Salmonella-infected MODE-K cells. Furthermore, the effects on epithelial barrier function and host defensin peptide (beta-defensin 3) was studied by measuring the mRNA expression level of tight junction protein (occludin) and beta-defensin 3 in MODE-K cells. The strain RW1 showed a considerable potential to survive in simulated gastrointestinal environmental conditions, low pH and high bile salt concentrations along with good adhesion to MODE-K cell line. Pathogenic bacterial growth and their adhesion to MODE-K cell line were significantly inhibited by the strain RW1. Real-time PCR analyses demonstrated that the strain RW1 inhibited Salmonella-induced pro-inflammatory cytokines (IL-6, IL-8 and IL-1ꞵ) production and reinforced the expression of tight junction protein (occludin). The strain RW1 did not induce mRNA expression of beta-defensin 3.

CONCLUSION

Based on in vitro results, the strain RW1 has the potential to be used as a probiotic supplement in dogs. However, further study involving in vivo health effects is needed.

SIGNIFICANCE AND IMPACT OF THE STUDY

Antibiotics have many side effects and nowadays the probiotics are considered as a potential alternative to antibiotics. This study evaluates the probiotic potential of dog isolated L. plantarum strain RW1 to use it as a dietary supplement in dogs feeding to control infectious diseases.

Enterococcus faecium HDRsEf1 inhibits LPS-induced downregulation of ZO-1 expression via TLR2/4-mediated JNK/AP-1 signalling pathways

AIMS

ZO-1 is a key regulatory tight junction protein that plays an important role in maintaining gastrointestinal health. In this study, we investigated the protective effect and regulation mechanism of the probiotic Enterococcus faecium HDRsEf1 on tight junction protein ZO-1 at the cellular and molecular levels.

METHODS AND RESULTS

We established LPS-induced intestinal epithelial cell injury model, and detected the protective effect of HDRsEf1 on ZO-1 in IPEC-J2 cells by Real-time PCR and Western blot. The results showed that HDRsEf1 inhibited the downregulation of ZO-1 expression induced by LPS. HDRsEf1 stabilized the destruction of the ZO-1 structure caused by LPS in an immunofluorescence assay. Through gene overexpression and siRNA interference tests, we found that transcription factor AP-1 inhibited the level of ZO-1 expression. Silencing experiment further supported that the protective effect of HDRSEF1 might mediated by suppression of LPS-provoked activation of ASK1/MKK7/JNK signalling pathways. In addition, HDRsEf1 could stabilize ZO-1 expression by increasing TLR2 expression and competing with LPS for the TLR4 binding site. More interestingly, we also found that HDRsEf1 could stabilize ZO-1 expression through inhibiting the production of TNF-α induced by LPS.

CONCLUSIONS

HDRsEf1 could protect the IPEC-J2 cell against LPS induced down-regulation of ZO-1 expression by inhibiting the activation of TLR2/4-mediated JNK-AP-1 and signalling cascade and the production of TNF-α.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study can provide a theoretical basis for probiotics to regulate the expression of intestinal tight junction proteins, and supply technical support for probiotics to prevent and treat animal intestinal infectious diseases.

Molecular characterization, developmental expression, and modulation of occludin by early intervention with Clostridium butyricum in Muscovy ducks

Occludin is an important component of tight junction proteins and has been extensively studied in animals such as mice, chickens, geese, and pigs. As one of the most important waterfowl species in China, Muscovy duck (Cairina moschata) is an important economic animal for meat. However, research on the occludin gene in Muscovy duck is lacking. In the present study, Muscovy duck occludin cDNA was cloned for the first time. The length of the cDNA was 1,699 bp, and it showed a high sequence similarity with the Anser cygnoides domesticus and Gallus gallus occludin genes. The occludin gene was differentially expressed in the tissues of healthy ducks. The highest and lowest expressions of occludin were observed in the crop and the spleen, respectively. After the oral administration of Clostridium butyricum (CB), the occludin expression in the ileum of 7-day-old Muscovy ducks was significantly upregulated and subsequently showed a decreasing trend in 14-day-old Muscovy ducks. Under the early intervention of CB, no significant difference was observed in the occludin expression of cecum between the control and CB group. Collectively, these results suggest that CB plays an important role in regulating the expression of the occludin gene in Muscovy ducks, and adding CB in feed may maintain the intestinal barrier of ducks by regulating the expression of occludin.

Colonization of Germ-Free Piglets with Mucinolytic and Non-Mucinolytic Bifidobacterium boum Strains Isolated from the Intestine of Wild Boar and Their Interference with Salmonella Typhimurium

Non-typhoidal Salmonella serovars are worldwide spread foodborne pathogens that cause diarrhea in humans and animals. Colonization of gnotobiotic piglet intestine with porcine indigenous mucinolytic Bifidobacterium boum RP36 strain and non-mucinolytic strain RP37 and their interference with Salmonella Typhimurium infection were compared. Bacterial interferences and impact on the host were evaluated by clinical signs of salmonellosis, bacterial translocation, goblet cell count, mRNA expression of mucin 2, villin, claudin-1, claudin-2, and occludin in the ileum and colon, and plasmatic levels of inflammatory cytokines IL-8, TNF-α, and IL-10. Both bifidobacterial strains colonized the intestine comparably. Neither RP36 nor RP37 B. boum strains effectively suppressed signs of salmonellosis. Both B. boum strains suppressed the growth of S. Typhimurium in the ileum and colon. The mucinolytic RP36 strain increased the translocation of S. Typhimurium into the blood, liver, and spleen.

Identification of differentially expressed miRNAs after Lactobacillus reuteri treatment in the ileum mucosa of piglets

BACKGROUND

Lactobacillus reuteri I5007 possesses many excellent probiotic characteristics in piglets. miRNA plays important role in host-microbiota interactions, but the mechanism by which L. reuteri I5007 regulates intestinal function through its influence on miRNA expression is unknown.

OBJECTIVE

This study analyzed the miRNA expression patterns in the ileum mucosa tissue of piglets by L. reuteri I5007 treatment, aim to clarify its molecular mechanism for regulating intestinal function through miRNA.

METHODS

Neonatal piglets were orally administered L. reuteri I5007 or a placebo daily starting on day 1, and differential expression of ileal miRNAs was analyzed at 10 and 20 days of age by small RNA sequencing.

RESULTS

361 known porcine miRNAs were identified, and ten miRNAs were highly expressed in the ileum mucosa in both treatments. Nineteen differentially expressed (DE) miRNAs were identified in response to L. reuteri treatment, and four DE miRNAs (ssc-miR-196a, -196b-5p, -1285 and -10386) were differentially expressed at both time points. The KEGG pathway analyses showed the targets of 19 DE miRNAs were involved in 63 significantly enriched pathways, including the PI3K-Akt and MAPK pathways, which were confirmed to play important roles in probiotic-host communication. L. reuteri I5007 exerted anti-inflammatory effects by influencing the levels of inflammatory cytokines. Suppressor of cytokine signalling 4 gene was the target gene of ssc-miR-196a/-196b-5p, overexpression of ssc-miR-196a/-196b-5p downregulated the mRNA expression of IL-1β and TNFα in IPEC-J2 cells.

CONCLUSION

Our study provides new insight into the role of miRNAs in the intestinal function of piglets after L. reuteri I5007 treatment.

Degeneration of the intestinal microbial community in PI3Kγ-knockout mice

BACKGROUND AND AIM

PI3Kγ is closely related to inflammation and cardiovascular diseases and thus, PI3Kγ inhibitors are candidate drugs for the treatment of these disorders. Considering the potential effect of the intestinal microbiome on inflammation and cardiovascular diseases, this study aimed to identify characteristics of the intestinal microbial community under PI3Kγ deficiency, to help reveal the potential influence of PI3Kγ inhibitors mediated by the microbial community.

METHODS

Exon 2 of the PI3Kγ gene was knocked out in a Balb/c mouse by using single-guide RNAs. Homozygous PI3Kγ-knockout (PI3Kγ-/-) mice were obtained by embryo transfer and hybridization. PI3Kγ-/- and wild-type (WT) mice were raised in the same specific pathogen-free conditions until 8 weeks of age. Then, colonic tissues and feces from the middle segment of the colon were collected and analyzed by Illumina MiSeq sequencing. Differences in intestinal microbial community between the PI3Kγ-/- and WT mice were detected by bioinformatics analysis.

RESULTS

The richness and alpha diversity of the colonic microbial community were decreased in PI3Kγ-/- mice. The alpha diversity of the microbial community in feces did not differ between PI3Kγ-/- and WT mice. The beta diversity of the microbial community in feces of PI3Kγ-/- mice was obviously different from that in WT mice, whereas the within-group variation in Bray-Curtis distances of the mucosal microbial community was significantly decreased in PI3Kγ-/- mice. The topological structure of the species-related network of the colonic microbial community in PI3Kγ-/- mice was more polarized. Finally, we predicted that PI3Kγ deficiency might affect the synthesis of some antibiotics, bile acid, and thiamine through effects on the microbial community.

CONCLUSIONS

PI3Kγ dysfunction led to degeneration of the intestinal microbial community and might alter the synthesis of some antibiotics, bile acids, and thiamine. The usage of PI3Kγ inhibitors for inflammation and cardiovascular diseases might lead to knock-on effect on our organism through intestinal microbiota.

Altered microbial community structure in PI3Kγ knockout mice with colitis impeding relief of inflammation: Establishment of new indices for intestinal microbial disorder

Lipopolysaccharide stimulates the intestinal microbiome to activate phosphoinositide 3 kinase (PI3K) signaling via several pathways; however, the direct effect that PI3K has on the intestinal bacterial community remains unclear. Herein, we investigate changes in the colonic microbiome of colitis PI3Kγ-knockout (PI3Kγ-/-) mice. Additionally, the effect of anal administration of colonic irrigation fluid from control mice to those with colitis was examined. Microbial 16S rRNA genes from the colonic mucosa of PI3Kγ-/- and WT mice were sequenced using Illumina MiSeq platform, and colonic IgA, IL-2, IL-10, and IL-17A production was quantified by western blot analysis. Myeloperoxidase (MPO) activity was detected by absorbance via colorimetric analysis. From the results, two new indices were derived by dividing the bacterial community into invading taxa, common taxa, and vanishing taxa. These indices were used to estimate the degree of microbiome disorder in chronic experimental colitis models. PI3Kγ-/- mice showed slower remission of inflammation as assessed by the disease activity index，pathological score, IL-2, IL-17, IL-10, IgA expression and MPO activity. The unique and common taxa of wild-type and PI3Kγ-/- mice increased as colitis symptoms regressed. Continuous loss of commensal bacteria happened with the continuous invasion of exogenous bacteria in the intestinal mucosa of PI3Kγ--/- mice after colitis begin to aggravate. However, transplantation of normal intestinal microbiota to PI3Kγ-/- mice promoted remission of inflammation; while the microbial dysbiosis observed during PI3Kγ dysfunction aggravated the intestinal microbiome disorder and impeded colitis recovery. Thus, the PI3Kγ signaling pathway may regulate microbial community composition in the colon.

Effects of a Four-Week High-Dosage Zinc Oxide Supplemented Diet on Commensal Escherichia coli of Weaned Pigs

Strategies to reduce economic losses associated with post-weaning diarrhea in pig farming include high-level dietary zinc oxide supplementation. However, excessive usage of zinc oxide in the pig production sector was found to be associated with accumulation of multidrug resistant bacteria in these animals, presenting an environmental burden through contaminated manure. Here we report on zinc tolerance among a random selection of intestinal Escherichia coli comprising of different antibiotic resistance phenotypes and sampling sites isolated during a controlled feeding trial from 16 weaned piglets: In total, 179 isolates from "pigs fed with high zinc concentrations" (high zinc group, [HZG]: n = 99) and a corresponding "control group" ([CG]: n = 80) were investigated with regard to zinc tolerance, antimicrobial- and biocide susceptibilities by determining minimum inhibitory concentrations (MICs). In addition, in silico whole genome screening (WGSc) for antibiotic resistance genes (ARGs) as well as biocide- and heavy metal tolerance genes was performed using an in-house BLAST-based pipeline. Overall, porcine E. coli isolates showed three different ZnCl₂ MICs: 128 μg/ml (HZG, 2%; CG, 6%), 256 μg/ml (HZG, 64%; CG, 91%) and 512 μg/ml ZnCl₂ (HZG, 34%, CG, 3%), a unimodal distribution most likely reflecting natural differences in zinc tolerance associated with different genetic lineages. However, a selective impact of the zinc-rich supplemented diet seems to be reasonable, since the linear mixed regression model revealed a statistically significant association between "higher" ZnCl₂ MICs and isolates representing the HZG as well as "lower ZnCl₂ MICs" with isolates of the CG (p = 0.005). None of the zinc chloride MICs was associated with a particular antibiotic-, heavy metal- or biocide- tolerance/resistance phenotype. Isolates expressing the 512 μg/ml MIC were either positive for ARGs conferring resistance to aminoglycosides, tetracycline and sulfamethoxazole-trimethoprim, or harbored no ARGs at all. Moreover, WGSc revealed a ubiquitous presence of zinc homeostasis and - detoxification genes, including zitB, zntA, and pit. In conclusion, we provide evidence that zinc-rich supplementation of pig feed selects for more zinc tolerant E. coli, including isolates harboring ARGs and biocide- and heavy metal tolerance genes - a putative selective advantage considering substances and antibiotics currently used in industrial pork production systems.

Pretreatment with probiotic Enterococcus faecium NCIMB 11181 ameliorates necrotic enteritis-induced intestinal barrier injury in broiler chickens

The dysfunction of tight-junction integrity caused by necrotic enteritis (NE) is associated with decreased nutrient absorption and gut injury in broiler chickens. Although probiotic Enterococcus faecium (E. faecium) has been reported to possess immune-regulatory characteristics and can prevent diarrhea in pigs, very little information exists in relation to the specific regulatory impact of E. faecium NCIMB 11181 on NE-induced intestinal barrier injury of broiler chickens. This study was conducted to investigate the protective effects of probiotic E. faecium NCIMB 11181 on NE-induced intestinal barrier injury in broiler chickens. The study also aimed to elucidate the mechanisms that underpin these protective effects. One hundred and eighty Arbor Acres (AA) broiler chicks (one day old) were randomly assigned using a 2 × 2 factorial arrangement into two groups fed different levels of dietary E. faecium NCIMB 11181 (0 or 2 × 10⁸ CFU/kg of diet) and two disease-challenge groups (control or NE challenged). The results showed that NE induced body weight loss, intestinal lesions, and histopathological inflammation, as well as intestinal-cell apoptosis. These symptoms were alleviated following the administration of probiotic E. faecium NCIMB 11181. Pretreatment with probiotic E. faecium NCIMB 11181 significantly upregulated the expression of the Claudin-1 gene encoding a tight-junction protein. Claudin-1 and HSP70 protein expression were also increased in the jejunum regardless of NE infection. Furthermore, NE-infected birds fed with E. faecium displayed notable increases in MyD88, NF-κB, iNOS, PI3K, GLP-2, IL-1β, IL-4, and HSP70 mRNA expression. E. faecium NCIMB 11181 administration also significantly improved the animals’ intestinal microbial composition regardless of NE treatment. These findings indicated that addition of E. faecium NCIMB 11181 to poultry feed is effective in mitigating NE-induced gut injury, possibly by strengthening intestinal mucosal barrier function, as well as modulating gut microflora and intestinal mucosal immune responses.