Adhesion of probiotic strains to the intestinal mucosa and interaction with pathogens

Investigation of the impact of multi-strain probiotics containing Saccharomyces cerevisiae on porcine production

A balanced intestinal microbiome controls intestinal bacterial diseases, helps regulate immunity, and digests and utilizes nutrients, ultimately having a positive effect on the productivity of industrial animals. Yeasts help in the digestion process by breaking down indigestible fibers and producing organic acids, vitamins, and minerals. In particular, polysaccharides such as beta-glucan and mannan-oligosaccharides, which are present in the cell wall of yeast, inhibit the adhesion of pathogens to the surface of the gastrointestinal tract and increase resistance to disease to help maintain and improve intestinal health. Among the yeast additives used in animal feed, Saccharomyces cerevisiae is one of the most commonly used probiotics. However, it does not naturally reside in the intestine, so if it is supplied in combination with other species of probiotics that can compensate for it, many benefits and synergies can be expected for pigs in terms of maintaining intestinal health such as supplementing the immune system and improving digestion. A number of previous studies have demonstrated that dietary complex probiotic supplementation has growth-promoting effects in pigs, suggesting that multiple strains of probiotics may be more effective than single strain probiotics due to their additive and synergistic effects. In practice, however, the effects of complex probiotics are not always consistent, and can be influenced by a variety of factors. Therefore, this review comprehensively examines and discusses the literature related to the effects of complex probiotics using Saccharomyces cerevisiae in pig production.

Water-soluble microencapsulation using gum Arabic and skim milk enhances viability and efficacy of Pediococcus acidilactici probiotic strains for application in broiler chickens

OBJECTIVE

This study aimed to develop and evaluate the effectiveness of a water-soluble microencapsulation method for probiotic strains using gum Arabic (GA) and skim milk (SKM) over a three-month storage period following processing.

METHODS

Four strains of Pediococcus acidilactici (BYF26, BYF20, BF9, and BF14) that were typical lactic acid bacteria (LAB) isolated from the chicken gut were mixed with different ratios of GA and SKM as coating agents before spray drying at an inlet temperature 140°C. After processing, the survivability and probiotic qualities of the strains were assessed from two weeks to three months of storage at varied temperatures, and de-encapsulation was performed to confirm the soluble properties. Finally, the antibacterial activity of the probiotics was assessed under simulated gastrointestinal conditions.

RESULTS

As shown by scanning electron microscopy, spray-drying produced a spherical, white-yellow powder. The encapsulation efficacy (percent) was greatest for a coating containing a combination of 30% gum Arabic: 30% skim milk (w/v) (GA:SKM30) compared to lower concentrations of the two ingredients (p<0.05). Coating with GA:SKM30 (w/v) significantly enhanced (p<0.05) BYF26 survival under simulated gastrointestinal conditions (pH 2.5 to 3) and maintained higher survival rates compared to non-encapsulated cells under an artificial intestinal juices condition of pH 6. De-encapsulation tests indicated that the encapsulated powder dissolved in water while keeping viable cell counts within the effective range of 106 for 6 hours. In addition, following three months storage at 4°C, microencapsulation of BYF26 in GA:SKM30 maintained both the number of viable cells (p<0.05) and the preparation's antibacterial efficacy against pathogenic bacteria, specifically strains of Salmonella.

CONCLUSION

Our prototype water-soluble probiotic microencapsulation GA:SKM30 effectively maintains LAB characteristics and survival rates, demonstrating its potential for use in preserving probiotic strains that can be used in chickens and potentially in other livestock.

Influence of Novel Microcapsulates of Bee Products on Gut Microbiota Modulation and Their Prebiotic and Pro-Adhesive Properties

With the aim to obtain controlled-release systems and to preserve the antioxidant, immunomodulatory, and prebiotic activity of the bioactive compounds, microencapsulation of both honeydew honey and royal jelly into biopolymeric microparticles based on rye bran heteropolysaccharides (HPS) was successfully performed. Honeydew honey and royal jelly microcapsules were prepared by spray-drying method and were characterized in terms of morphology and biological properties. Due to the resistance of the obtained encapsulates to the acidic pH in the stomach and digestive enzymes, the microcapsules showed prebiotic properties positively influencing both the growth, retardation of the dying phase, and the pro-adhesive properties of probiotic bacteria, i.e., Bifidobacterium spp. and lactic acid bacteria. Moreover, as a result of fermentation of the microcapsules of bee products in the lumen of the large intestine, an increased synthesis of short-chain fatty acids, i.e., butyric acid, was found on average by 39.2% in relation to the SCFA concentrations obtained as a result of fermentation of native bee products, thus opening new perspectives for the exploitation of honeydew honey and royal jelly loaded microcapsules for nutraceutical applications.

Antioxidant Effects and Probiotic Properties of Latilactobacillus sakei MS103 Isolated from Sweet Pickled Garlic

Fermented vegetable-based foods, renowned for their unique flavors and human health benefits, contain probiotic organisms with reported in vitro antioxidative effects. This study investigates the probiotic properties of Latilactobacillus sakei MS103 (L. sakei MS103) and its antioxidant activities using an in vitro oxidative stress model based on the hydrogen peroxide (H2O2)-induced oxidative damage of RAW 264.7 cells. L. sakei MS103 exhibited tolerance to extreme conditions (bile salts, low pH, lysozyme, H2O2), antibiotic sensitivity, and auto-aggregation ability. Moreover, L. sakei MS103 co-aggregated with pathogenic Porphyromonas gingivalis cells, inhibited P. gingivalis-induced biofilm formation, and exhibited robust hydrophobic and electrostatic properties that enabled it to strongly bind to gingival epithelial cells and HT-29 cells for enhanced antioxidant effects. Additionally, L. sakei MS103 exhibited other antioxidant properties, including ion-chelating capability and the ability to effectively scavenge superoxide anion free radicals, hydroxyl, 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid, and 2,2-diphenyl-1-picrylhydrazyl. Furthermore, the addition of live or heat-killed L. sakei MS103 cells to H2O2-exposed RAW 264.7 cells alleviated oxidative stress, as reflected by reduced malondialdehyde levels, increased glutathione levels, and the up-regulated expression of four antioxidant-related genes (gshR2, gshR4, Gpx, and npx). These findings highlight L. sakei MS103 as a potential probiotic capable of inhibiting activities of P. gingivalis pathogenic bacteria and mitigating oxidative stress.

Comprehensive probiogenomics analysis of the commensal Escherichia coli CEC15 as a potential probiotic strain

BACKGROUND

Probiotics have gained attention for their potential maintaining gut and immune homeostasis. They have been found to confer protection against pathogen colonization, possess immunomodulatory effects, enhance gut barrier functionality, and mitigate inflammation. However, a thorough understanding of the unique mechanisms of effects triggered by individual strains is necessary to optimize their therapeutic efficacy. Probiogenomics, involving high-throughput techniques, can help identify uncharacterized strains and aid in the rational selection of new probiotics. This study evaluates the potential of the Escherichia coli CEC15 strain as a probiotic through in silico, in vitro, and in vivo analyses, comparing it to the well-known probiotic reference E. coli Nissle 1917. Genomic analysis was conducted to identify traits with potential beneficial activity and to assess the safety of each strain (genomic islands, bacteriocin production, antibiotic resistance, production of proteins involved in host homeostasis, and proteins with adhesive properties). In vitro studies assessed survival in gastrointestinal simulated conditions and adhesion to cultured human intestinal cells. Safety was evaluated in BALB/c mice, monitoring the impact of E. coli consumption on clinical signs, intestinal architecture, intestinal permeability, and fecal microbiota. Additionally, the protective effects of both strains were assessed in a murine model of 5-FU-induced mucositis.

RESULTS

CEC15 mitigates inflammation, reinforces intestinal barrier, and modulates intestinal microbiota. In silico analysis revealed fewer pathogenicity-related traits in CEC15, when compared to Nissle 1917, with fewer toxin-associated genes and no gene suggesting the production of colibactin (a genotoxic agent). Most predicted antibiotic-resistance genes were neither associated with actual resistance, nor with transposable elements. The genome of CEC15 strain encodes proteins related to stress tolerance and to adhesion, in line with its better survival during digestion and higher adhesion to intestinal cells, when compared to Nissle 1917. Moreover, CEC15 exhibited beneficial effects on mice and their intestinal microbiota, both in healthy animals and against 5FU-induced intestinal mucositis.

CONCLUSIONS

These findings suggest that the CEC15 strain holds promise as a probiotic, as it could modulate the intestinal microbiota, providing immunomodulatory and anti-inflammatory effects, and reinforcing the intestinal barrier. These findings may have implications for the treatment of gastrointestinal disorders, particularly some forms of diarrhea.

Characterization of lactic acid bacteria isolated from the poultry intestinal environment with anti-Salmonella activity in vitro

The purpose of this research was the genotypic identification of lactic acid bacteria (LAB), isolated from the gastrointestinal tract (GIT) of healthy adult birds, and the study of their safety regarding antibiotic resistance, physiological and functional properties involved in the colonization of the GIT of poultry, and Salmonella exclusion, as members of a potential mixed probiotic supplement for poultry. The nucleotidic sequence from Lactobacillus crispatus P1, L. animalis L3, and Enterococcus faecium CRL 1385 (ex-J96) showed 100, 99.8, and 99.3% identity with L. crispatus DSM 20584 T, Ligilactobacillus salivarius ATCC 11741 T, and E. faecium ATCC 19434 T, respectively. These strains showed no resistance to relevant antibiotics usually administered to animals proposed by the European Food Safety Authority. They could endure the detrimental conditions of the gastrointestinal tract (pH 2.6 and oxgall 0.1 and 0.4% w/v). In an ex vivo assay, the LAB showed high adherence to the three sections of the GIT, reaching values higher than 70%. The adhesion to mucus was strain-dependent: L. crispatus CRL 1453 evidenced the highest adhesion (> 19%) while Lig. salivarius subsp. salivarius CRL 1417 and E. faecium CRL 1385 adhered to a lower extent (> 9 and 2%, respectively). Moreover, the LAB elicited remarkable anti-Salmonella activity, taking into account that they could inhibit elevated counts of different Salmonella serovars, especially the host-specific serovars S. Gallinarum and S. Pullorum (up to 8 log CFU/mL decrease in Salmonella counts).

Evaluation of Probiotic Properties of Novel Brazilian Lactiplantibacillus plantarum Strains

Beneficial effects of Lactiplantibacillus plantarum strains have been widely reported. Knowing that the effects of probiotic bacteria are strain-dependent, this study aimed to characterize the probiotic properties and investigate the gastrointestinal protective effects of nine novel L. plantarum strains isolated from Bahia, Brazil. The probiotic functionality was first evaluated in vitro by characterizing bile salt and acidic tolerance, antibacterial activity, and adhesion to Caco-2 cells. Antibiotic resistance profile, mucin degradation, and hemolytic activity assays were also performed to evaluate safety features. In vivo analyses were conducted to investigate the anti-inflammatory effects of the strains on a mouse model of 5-Fluorouracil-induced mucositis. Our results suggest that the used L. plantarum strains have good tolerance to bile salts and low pH and can inhibit commonly gastrointestinal pathogens. Lp2 and Lpl1 strains also exhibited high adhesion rates to Caco-2 cells (13.64 and 9.05%, respectively). Phenotypical resistance to aminoglycosides, vancomycin, and tetracycline was observed for most strains. No strain showed hemolytic or mucolytic activity. Seven strains had a protective effect against histopathological and inflammatory damage induced by 5-FU. Gene expression analysis of inflammatory markers showed that five strains upregulated interleukin 10 (Il10), while four downregulated both interleukin 6 (Il6) and interleukin 1b (Il1b). Additionally, all strains reduced eosinophilic and neutrophilic infiltration; however, they could not prevent weight loss or reduced liquid/ food intake. Altogether, our study suggests these Brazilian L. plantarum strains present good probiotic characteristics and safety levels for future applications and can be therapeutically adjuvant alternatives to prevent/treat intestinal mucositis.

Inhibition of Listeria monocytogenes Growth, Adherence and Invasion in Caco-2 Cells by Potential Probiotic Lactic Acid Bacteria Isolated from Fecal Samples of Healthy Neonates

Lactic acid bacteria (LAB) isolated from healthy humans may prove an effective tool against pathogen growth, adherence and invasion in intestinal epithelial cells. This study aimed to evaluate the antilisterial properties of LAB isolated from fecal samples of healthy neonates. Forty-five LAB strains were tested for their antimicrobial activity against ten Listeria monocytogenes strains with spot-on-lawn and agar-well diffusion assays, and ten lactobacilli strains were further assessed for their inhibitory effect against adherence and invasion of Caco-2 cells by L. monocytogenes EGDe. Inhibition was estimated in competition, exclusion or displacement assays, where lactobacilli and L. monocytogenes were added to Caco-2 monolayers simultaneously or 1 h apart from each other. Inhibition of L. monocytogenes growth was only displayed with the spot-on-lawn assay; cell-free supernatants of lactobacilli were not effective against the pathogen. Lactobacillus (L.) paragasseri LDD-C1 and L. crispatus LCR-A21 were able to adhere to Caco-2 cells at significantly higher levels than the reference strain L. rhamnosus GG. The adherence of L. monocytogenes to Caco-2 cells was reduced by 20.8% to 62.1% and invasion by 33.5% to 63.1% during competition, which was more effective compared to the exclusion and displacement assays. These findings demonstrate that lactobacilli isolated from neonatal feces could be considered a good candidate against L. monocytogenes.

Mucosal Immunity and the Gut-Microbiota-Brain-Axis in Neuroimmune Disease

Recent advances in next-generation sequencing (NGS) technologies have opened the door to a wellspring of information regarding the composition of the gut microbiota. Leveraging NGS technology, early metagenomic studies revealed that several diseases, such as Alzheimer's disease, Parkinson's disease, autism, and myalgic encephalomyelitis, are characterized by alterations in the diversity of gut-associated microbes. More recently, interest has shifted toward understanding how these microbes impact their host, with a special emphasis on their interactions with the brain. Such interactions typically occur either systemically, through the production of small molecules in the gut that are released into circulation, or through signaling via the vagus nerves which directly connect the enteric nervous system to the central nervous system. Collectively, this system of communication is now commonly referred to as the gut-microbiota-brain axis. While equally important, little attention has focused on the causes of the alterations in the composition of gut microbiota. Although several factors can contribute, mucosal immunity plays a significant role in shaping the microbiota in both healthy individuals and in association with several diseases. The purpose of this review is to provide a brief overview of the components of mucosal immunity that impact the gut microbiota and then discuss how altered immunological conditions may shape the gut microbiota and consequently affect neuroimmune diseases, using a select group of common neuroimmune diseases as examples.

Management of Pediatric Urinary Tract Infections: A Delphi Study

Urinary tract infection (UTI) is one of the most common infectious diseases in the pediatric population and represents a major cause of antibiotic consumption and hospitalization in children. Considering the ongoing controversies on the management of pediatric UTI and the challenges due to increasing antimicrobial resistance, the aim of the present study was to evaluate the level of agreement on UTI management in pediatric age in Emilia-Romagna Region, Italy, and to assess on the basis of recent studies whether there is the need to change current recommendations used by primary care pediatricians, hospital pediatricians, and pediatric surgeons in everyday clinical practice to possibly improve outcomes. This consensus provides clear and shared indications on UTI management in pediatric age, based on the most updated literature. This work represents, in our opinion, the most complete and up-to-date collection of statements on procedures to follow for pediatric UTI, in order to guide physicians in the management of the patient, standardize approaches, and avoid abuse and misuse of antibiotics. Undoubtedly, more randomized and controlled trials are needed in the pediatric population to better define the best therapeutic management in cases with antimicrobial resistance and real usefulness of long-term antibiotic prophylaxis.

Bacillus subtilis Expressing the Infectious Pancreatic Necrosis Virus VP2 Protein Retains Its Immunostimulatory Properties and Induces a Specific Antibody Response

Bacillus subtilis has been documented in the past years as an effective probiotic for different aquacultured species, with recognized beneficial effects on water quality, fish growth and immune status. Furthermore, its potential as a vaccine adjuvant has also been explored in different species. In the current work, we have used B. subtilis spores as delivery vehicles for the presentation of the VP2 protein from infectious pancreatic necrosis virus (IPNV). For this, the VP2 gene was amplified and translationally fused to the crust protein CotY. The successful expression of VP2 on the spores was confirmed by Western blot. We then compared the immunostimulatory potential of this VP2-expressing strain (CRS208) to that of the original B. subtilis strain (168) on rainbow trout (Oncorhynchus mykiss) leukocytes obtained from spleen, head kidney and the peritoneal cavity. Our results demonstrated that both strains significantly increased the percentage of IgM⁺ B cells and the number of IgM-secreting cells in all leukocyte cultures. Both strains also induced the transcription of a wide range of immune genes in these cultures, with small differences between them. Importantly, specific anti-IPNV antibodies were detected in fish intraperitoneally or orally vaccinated with the CRS208 strain. Altogether, our results demonstrate B. subtilis spores expressing foreign viral proteins retain their immunomodulatory potential while inducing a significant antibody response, thus constituting a promising vaccination strategy.

Mucosal and systemic immune effects of Bacillus subtilis in rainbow trout (Oncorhynchus mykiss)

Bacillus spp. are well known for their probiotic properties. Hence, the long-term feeding of Bacillus spp. strains to different fish species has been proved to confer beneficial effects regarding growth or pathogen resistance, among others. However, whether these strains could function as mucosal adjuvants, up-regulating immune responses after a single administration, has not yet been investigated in fish. Thus, in the current work, we have performed a series of experiments in rainbow trout (Oncorhynchus mykiss) aimed at establishing the potential of two Bacillus subtilis spore-forming strains, designated as ABP1 and ABP2, as oral adjuvants/immunostimulants. As an initial step, we evaluated their transcriptional effects on the rainbow trout intestinal epithelial cell line RTgutGC, and in gut tissue explants incubated ex vivo with the two strains. Their capacity to adhere to RTgutGC cells was also evaluated by flow cytometry. Although both strains had the capacity to modulate the transcription of several genes related to innate and adaptive immune responses, it was the ABP1 strain that led to stronger transcriptional effects, also exerting a higher binding capacity to intestinal epithelial cells. Consequently, we selected this strain to establish its effects on splenic B cells upon in vitro exposure as well as to determine the transcriptional effects exerted in the spleen, kidney, and gut after a single oral administration of the bacteria. Our results showed that B. subtilis ABP1 had the capacity to modulate the proliferation, IgM secreting capacity and MHC II surface expression of splenic B cells. Finally, we confirmed that this strain also induced the transcription of genes involved in inflammation, antimicrobial genes, and genes involved in T cell responses upon a single oral administration. Our results provide valuable information regarding how B. subtilis modulates the immune response of rainbow trout, pointing to the usefulness of the ABP1 strain to design novel oral vaccination strategies for aquaculture.

Ileal microbial composition in genetically distinct chicken lines reared under normal or high ambient temperatures

Background

Heat stress (HS) has negative effects on poultry productivity, health and welfare resulting in economic losses. Broiler chickens are particularly susceptible to HS due to their high metabolic rate and rapid growth. The commensal intestinal bacterial populations have an important physiological role in the host and could ameliorate the negative effect of HS on the host. Thus, the aim of this study was to compare changes in the ileal (IL) microbiota in four different broiler lines during HS.

Results

Day-old broiler chicks from Giant Jungle Fowl (JF), Athens Canadian Random Bred (ACRB), 1995 Random Bred (L1995), and Modern Random Bred (L2015) lines were raised under thermoneutral (TN) conditions until day (d) 28. On d 29 birds were subjected to TN (24 °C) or chronic cyclic HS (8 h/d, 36 °C) condition till d 56. On d 56 two birds per pen were euthanized, and IL luminal content (IL-L) and mucosal scrapings (IL-M) were collected for bacterial DNA isolation. Libraries were constructed using V3–V4 16S rRNA primers and sequenced using MiSeq. DNA sequences were analyzed using QIIME2 platform and SILVA 132 database for alpha and beta diversity, and taxonomic composition, respectively. Functional property of microbiota was predicted using the PICRUSt 2 pipeline and illustrated with STAMP software. Shannon index was significantly elevated in IL-M under HS. β-diversity PCoA plots revealed separation of microbial community of L2015-TN from JF-TN, JF-HS, ACRB-TN, and ACRB-HS in the IL-M. PERMANOVA analysis showed a significant difference between microbial community of L1995-HS compared to ACRB-HS and JF-TN, L1995-TN compared to ACRB-HS and JF-TN, L2015-HS compared to ACRB-HS and ACRB-TN, L2015-HS compared to JF-TN, L2015-TN compared to ACRB-HS and JF-TN, and ACRB-HS compared to JF-TN in the IL-L. The impact of HS on microbial composition of IL-M was more prominent compared to IL-L with 12 and 2 taxa showing significantly different relative abundance, respectively. Furthermore, differences in microbiota due to the genetic line were more prominent in IL-M than IL-L with 18 and 8 taxa showing significantly different relative abundance, respectively. Unlike taxonomy, predicted function of microbiota was not affected by HS. Comparison of L2015 with JF or ACRB showed significant changes in predicted function of microbiota in both, IL-M and IL-L. Differences were most prominent between L2015 and JF; while there was no difference between L2015 and L1995.

Conclusions

These data indicate the genetic line × temperature effect on the diversity and composition of IL microbiota. Moreover, the data showcase the effect of host genetics on the composition of IL microbiota and their predicted function. These data are of critical importance for devising nutritional strategies to maintain GIT microbial balance and alleviate the negative effects of HS on broiler chickens’ performance and health.

Supplementary Information

The online version contains supplementary material available at 10.1186/s42523-022-00183-y.

Anti-inflammation and adhesion enhancement properties of the multifunctional LPxTG-motif surface protein derived from the Lactobacillus reuteri DSM 8533

LPxTG-motif protein (LMP) is one kind of a precursor protein that contains a conserved LPxTG-motif at the C-terminus, which can be recognized by sortase A (SrtA) and covalently bind to the bacterial peptidoglycan. In this study, LMP derived from Lactobacillus reuteri (L. reuteri) was heterologous expressed and the tolerance and intestinal colonization ability of the LMP on L. reuteri were analyzed in simulated gastrointestinal fluid. Meanwhile, the anti-inflammatory activity of LMP was also evaluated in the LPS-stimulated RAW 264.7 cell model. The results indicated that LMP can promote the intestinal survival rate and adhesion characteristics of L. reuteri and enhanced the autoinducer-2 (AI-2) signaling molecule of the Lactobacillus strains in quorum sensing. Furthermore, LMP can inhibit the expressions of inflammatory cytokine TNF-α and IL-1β via ERK-JNK related MAPK signaling cascades. These findings provide a better understanding of the multifunctional LPxTG-motif surface protein derived from L. reuteri in the gastrointestinal tract environment.

A novel Lactobacillus bulgaricus isolate can maintain the intestinal health, improve the growth performance and reduce the colonization of E. coli O157:H7 in broilers

1. This study aimed at the effects of a novel Lactobacillus bulgaricus (L. bulgaricus) strain and Enterohemorrhagic Escherichia coli (E. coli) O157: H7 on intestinal flora and growth performance of broilers, and the protective effect of L. bulgaricus on broilers in challenged experiment by E. coli O157: H7.2. In vitro bacteriostatic test showed that the cell-free supernatant (CFS) of L. bulgaricus isolate had obvious inhibitory effect on E. coli O157: H7.3. Eighty 1-day-old male broilers were randomly assigned into 4 treatment groups with 4 replicate per treatment. All group received basic diet in addition to the specific treatments: NC group, gavage with normal saline; In LBP group, gavage with L. bulgaricus isolate (1×10⁹ CFU/mL) during the whole process, and challenged with E. coli O157: H7 (3×10⁹ CFU/mL); EC group, gavage with E. coli O157: H7 (3×10⁹ CFU/mL); LB Group, gavage with L. bulgaricus isolate. At the age of 21 days, broilers were weighed and feed conversion ratio (FCR) was calculated. Cecum and cecal contents, ileum and feces samples were taken after slaughter.4. The challenge of E. coli O157: H7 resulted in an increase in TLR-4, NF-κB and IL-8 mRNA in cecal tissue, a decrease in Villus: crypt ratio in ileum, a decrease in overall diversity of intestinal microflora and a poor FCR.5. The L. bulgaricus isolate decreased the mRNA expression of TLR-4, NF-κB and IL-8 induced by E. coli O157: H7, reduced the content of E. coli O157: H7 in the cecum of broilers, increased the Villus: crypt ratio, increased the abundance of beneficial bacteria and overall diversity of intestinal microflora, made good FCR.6. The L. bulgaricus isolate can maintain the intestinal health, improve the growth performance of broilers and reduce the colonization of E. coli O157:H7 in the cecum.

Contributions of the microbiome to intestinal inflammation in a gut-on-a-chip

The intestinal microbiome affects a number of biological functions of the organism. Although the animal model is a powerful tool to study the relationship between the host and microbe, a physiologically relevant in vitro human intestinal system has still unmet needs. Thus, the establishment of an in vitro living cell-based system of the intestine that can mimic the mechanical, structural, absorptive, transport and pathophysiological properties of the human intestinal environment along with its commensal bacterial strains can promote pharmaceutical development and potentially replace animal testing. In this paper, we present a microfluidic-based gut model which allows co-culture of human and microbial cells to mimic the gastrointestinal structure. The gut microenvironment is recreated by flowing fluid at a low rate (21 μL/h) over the microchannels. Under these conditions, we demonstrated the capability of gut-on-a-chip to recapitulate in vivo relevance epithelial cell differentiation including highly polarized epithelium, mucus secretion, and tight membrane integrity. Additionally, we observed that the co-culture of damaged epithelial layer with the probiotics resulted in a substantial responded recovery of barrier function without bacterial overgrowth in a gut-on-a-chip. Therefore, this gut-on-a-chip could promote explorations interaction with host between microbe and provide the insights into questions of fundamental research linking the intestinal microbiome to human health and disease.

Nonpharmacological Treatment Strategies for the Management of Canine Chronic Inflammatory Enteropathy—A Narrative Review

Chronic inflammatory enteropathy (CIE) refers to a heterogeneous group of idiopathic diseases of the dog characterised by persistent gastrointestinal (GI) clinical signs. If conventional dietary treatment alone would be unsuccessful, management of CIE is traditionally attained by the use of pharmaceuticals, such as antibiotics and immunosuppressive drugs. While being rather effective, however, these drugs are endowed with side effects, which may impact negatively on the animal’s quality of life. Therefore, novel, safe and effective therapies for CIE are highly sought after. As gut microbiota imbalances are often associated with GI disorders, a compelling rationale exists for the use of nonpharmacological methods of microbial manipulation in CIE, such as faecal microbiota transplantation and administration of pre-, pro-, syn- and postbiotics. In addition to providing direct health benefits to the host via a gentle modulation of the intestinal microbiota composition and function, these treatments may also possess immunomodulatory and epithelial barrier-enhancing actions. Likewise, intestinal barrier integrity, along with mucosal inflammation, are deemed to be two chief therapeutic targets of mesenchymal stem cells and selected vegetable-derived bioactive compounds. Although pioneering studies have revealed encouraging findings regarding the use of novel treatment agents in CIE, a larger body of research is needed to address fully their mode of action, efficacy and safety.

Lactobacillus casei reduces the extracellular matrix components of fluconazole-susceptible Candida albicans biofilms

Fluconazole-sensitive (CaS) and -resistant (CaR) C. albicans were grown as single-species and dual-species biofilms with Lactobacillus casei (Lc) and Lactobacillus rhamnosus (Lr). Single-species Lc and Lr were also evaluated. Biofilm analysis included viable plate counts, the extracellular matrix components, biomass, and structural organization. Lc reduced the viability of CaS, water-soluble polysaccharides, and eDNA in CaS + Lc biofilm. Lc biofilm presented more eDNA than CaS. The total biomass of CaS + Lc biofilm was higher than the single-species biofilms. The viability of Lc and Lr was reduced by CaR dual-species biofilms. The total and insoluble biomass in CaS + Lr was higher than in single-species CaS biofilms. Lc hindered the growth of CaS, and their association hampered matrix components linked to the structural integrity of the biofilm. These findings allow understanding of how the implementation of probiotics influences the growth of C. albicans biofilms and thereby helps with the development of novel approaches to control these biofilms.

Deciphering the Probiotic Potential of Bacillus amyloliquefaciens COFCAU_P1 Isolated from the Intestine of Labeo rohita Through In Vitro and Genetic Assessment

In this study, a bacterial strain COFCAU_P1, isolated from the digestive tract of a freshwater teleost rohu (Labeo rohita), was identified as Bacillus amyloliquefaciens using 16S rRNA gene sequence analysis combined with amplification of species-specific BamHI and barnase genes. The probiotic potential of the strain was evaluated using an array of in vitro tests along with safety and genetic analyses. The isolate showed potent antimicrobial response against several fish pathogenic bacteria, survived a wide pH range (2-9), and was resistant up to 10% bile salt concentration. With regard to the in vitro adhesion properties, the strain showed significantly high in vitro adhesion to mucus, auto and co-aggregation capacity, and cell surface hydrophobicity. The strain was non-haemolytic, able to produce extracellular enzymes, viz., proteinase, amylase, lipase, and cellulase, and showed significant free radical scavenging activity. A challenge study in rohu revealed the strain COFCAU_P1 as non-pathogenic. The presence of putative probiotic marker genes including 2, 3-bisphosphoglycerate-independent phosphoglycerate mutase, arginine/ornithine antiporter ArcD, choloylglycine hydrolase, LuxS, and E1 β-subunit of the pyruvate dehydrogenase complex was confirmed by PCR, suggesting the molecular basis of the probiotic-specific functional attributes of the isolate. In conclusion, the in vitro and genetic approaches enabled the identification of a potential probiotic from autochthonous source with a potential of its utilization in the aquaculture industry.

Cell surface and extracellular proteins of potentially probiotic Lactobacillus reuteri as an effective mediator to regulate intestinal epithelial barrier function

The present study aimed to evaluate the potential of cell surface and extracellular proteins in regulation of intestinal epithelial barrier (IEB) function. Eight potentially probiotic L. reuteri strains were evaluated for presence of mapA gene and its expression on co-culturing with the Caco-2 cells. The ability of untreated (Viable), heat-inactivated, 5 M LiCL treated L. reuteri strains as well as their cell-free supernatant (CFS) to modulate expression of IEB function genes (hBD-2, hBD-3, claudin-1 and occludin) was also evaluated. Caco-2 cells were treated with cell surface and extracellular protein extracts and investigated for change in expression of targeted IEB function genes. The results showed that mapA gene is present in all the tested L. reuteri strains and expression of mapA and its receptors (anxA13 and palm) increase significantly on co-culturing of L. reuteri and Caco-2 cells. Also, up-regulated expression of IEB function genes was observed on co-culturing of L. reuteri (viable, heat-inactivated and CFS) and their protein extracts with Caco-2 cells in contrast to down-regulation observed with the pathogenic strain of Salmonella typhi. Therefore, this study concludes that the cell surface and extracellular protein from L. reuteri act as an effective mediator molecules to regulate IEB function.

Identification of Synbiotics Conducive to Probiotics Adherence to Intestinal Mucosa Using an In Vitro Caco-2 and HT29-MTX Cell Model

The ability of bacteria to adhere to the intestinal mucosa is a critical property necessary for the long-term colonization of the intestinal tract. This ability can be highly sensitive to the presence of prebiotics. However, limited data are available in this respect for beneficial bacteria such as probiotics or resident gut microbiota. We previously demonstrated that the presence of prebiotics may decrease adherence in several pre- and probiotic combinations. Thus, characterizing the interactions between numerous combinations involving different classes of pre- and probiotics can be crucial in identifying new synbiotics. Accordingly, here, we extend our prior analyses to evaluate the adhesion of five lactobacilli, six bifidobacteria, and one probiotic Escherichia coli strains, as commercial probiotics or promising probiotic candidates, together with the cariogenic Bifidobacterium dentium strain. As an in vitro intestinal mucosa model, Caco-2 and mucin-secreting HT29-MTX cells were co-cultured at 9:1 in the presence or absence of prebiotics. Commercial inulin-type fructooligosaccharide prebiotics Orafti® GR, Orafti® P95, and galactooligosaccharide-based prebiotic formula Vivinal®, including purified human milk oligosaccharides (HMOs) were added into the cultivation media as the sole sugar source (2.5% each). Adherence was tested using microtiter plates and was evaluated as the percentage of fluorescently labeled bacteria present in the wells after three washes. Consistent prebiotics-mediated enhanced adherence was observed only for the commercial probiotic strain E. coli O83. For the remaining strains, the presence of HMO or prebiotics Orafti® P95 or Orafti® GR decreased adherence, reaching statistical significance (p < 0.05) for three of out of eight (HMO) or five of out of 11 strains tested, respectively. Conversely, Vivinal® enhanced adhesion in six out of the 12 strains tested, and notably, it significantly attenuated the adherence of the cariogenic Bifidobacterium dentium Culture Collection of Dairy Microorganisms (CCDM) 318. To our knowledge, this represents the first report on the influence of commercial prebiotics and HMOs on the adhesion of the cariogenic Bifidobacterium sp. Vivinal® seems to be a promising prebiotic to be used in the formulation of synbiotics, supporting the adhesion of a wide range of probiotics, especially the strains B. bifidum BBV and BBM and the probiotic Escherichia coli O83.

Interaction between the probiotic Bacillus subtilis and Salmonella Typhimurium in Caco-2 cell culture

Background and Objectives:

Bacillus probiotics have been recently considered in biotechnological researches, and food additives. The present study was aimed to investigate the effects of Bacillus subtilis probiotics (PY79 and ATCC 6633) and their metabolites on Salmonella Typhimurium in Caco-2 cells.

Materials and Methods:

Cytotoxicity of B. subtilis ATCC 6633 crude supernatant (CS) was evaluated by 3-(4,5 dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. S. Typhimurium invasion assay was performed in the presence of the probiotics. Cell viability, apoptosis, and necrosis were evaluated in presence of S. Typhimurium, B. subtilis strains, and CS (4%, 8%) using flow cytometry.

Results:

Results showed a significant reduction in the invasive ability of S. Typhimurium to Caco-2 cells by employing B. subtilis probiotics, and CS (p < 0.05). The less invasion was indicated in B. subtilis PY79 and Salmonella co-cultural group. Furthermore, the cell survival rates, and apoptosis/necrosis were respectively increased and decreased in co-culture groups (p < 0.05).

Conclusion:

Hence, it seems that B. subtilis strains could be suggested as beneficial candidates to overcome the invasion and cytotoxicity of Salmonella on the intestinal cells. However, additional in vivo models are suggested to validate our results.

Managing broilers gut health with antibiotic-free diets during subclinical necrotic enteritis

Necrotic enteritis (NE) caused by Clostridium perfringens is among the most important enteric diseases in poultry production. This study examined the effects of 2 probiotics (Prob) and a synbiotic (Synb) during a naturally occurring NE challenge. On the day of hatch, 1200 Cobb male broilers were randomly allocated to 5 groups (8 pens/treatment, 30 birds/pen) including 1) negative control (NC): corn-soybean meal diet; 2) positive control (PC): NC + 453 g Stafac20/907 kg feed; 3) Prob 1: NC + 453 g Prob 1/907 kg feed; 4) Prob 2: NC + 453 g Prob 2/907 kg feed; and 5) Synb: NC + 453 g Synb/907 kg feed. One day after placement, birds were challenged by a coccidia vaccine to induce NE. Feed intake and body weights were measured on day 8 (NE onset) and end of starter (day 14) and grower (28) periods. On day 8, the small intestines of 3 birds/pen were examined for NE lesions. Ileal mucosal scrapings from one bird/pen were collected on day 8 and day 28 to profile the microbiota using 16S rRNA sequencing. Data were analyzed in JMP or QIIME 2 and significance between treatments identified by LSD or linear discriminant analysis effect size (P < 0.05). The Synb group significantly lowered NE lesion scores on day 8 and reduced day 0-14 mortality by 50% compared with NC. FCR was significantly better in all the groups, whereas ADG was higher in PC, Synb, and Prob 2 groups compared with NC from day 0 to day 28. Lower lesion scores in the Synb group were accompanied by lower relative abundance of Alistipes, ASF356, Faecalibaculum, Lachnospiraceae UCG-001, Muribaculum, Oscillibacter, Parabacteroides, Rikenellaceae RC9 gut group, Ruminococcaceae UCG-014, and Ruminiclostridium 9 compared with NC on day 8. On day 28, relative abundance of Lactobacillus was lower, whereas abundance of Bacteroides, Barnesiella, Butyricicoccus, CHKCI001, Eisenbergiella, Eubacterium hallii group, Helicobacter, Ruminococcaceae UCG-005, Ruminococcus torques group, and Sellimonas was significantly higher in the NC birds than in the Synb and Prob 2 groups. Collectively, these data indicate that during a subclinical naturally occurring NE, supplementation of specific additives could be effective in reducing intestinal lesions and mortality, and improving performance potentially through developing a signature microbial profile in the intestinal mucosal layer.

Electrospun Scaffold for Biomimic Culture of Caco-2 Cell Monolayer as an In Vitro Intestinal Model

The Caco-2 cell monolayer has been extensively used for the high-throughput assessing of nutrient absorption, screening of drug permeability, and studying the intestinal physiological process in vitro. The most used Caco-2 cell model is the Transwell model with polycarbonate microporous membranes. However, Caco-2 cells in the classical Transwell model need 21 days to gain an intact and mature monolayer. Electrospun nanofiber scaffolds mimicking the natural extracellular matrix could improve cell adhesion, proliferation, and expression, whereas there are no reports that intestinal cells were cultured on the electrospun nanofiber scaffolds. Here, electrospun polylactic acid (PLA) nanofiber scaffolds were chosen as the ideal scaffolds for Caco-2 cell monolayers to construct a modified Transwell. Cell morphology and polarity were studied. Monolayer barrier properties were assessed by measuring transepithelial electrical resistance (TEER) and the leakage of phenol red. As found, intact Caco-2 cell monolayers were formed on the PLA nanofiber scaffolds after 4 days of culture. After 4 days, the TEER increased to 422 Ω·cm² and the apparent permeability coefficients of phenol red decreased to 1.0 ± 0.1 × 10^-6 cm/s, suggesting that Caco-2 cell monolayers developed a formidable barrier to small molecules on the surface of PLA nanofiber scaffolds. Microvilli and tight junctions were clearly visible after day 3. Besides, Caco-2 cell monolayers on the surface of PLA nanofiber scaffolds presented higher differentiation properties than on the surface of the polycarbonate microporous membrane in traditional Transwell including higher alkaline phosphatase activity and higher P-gp activity. Results of quercetin absorption and probiotics adhesion demonstrated that Caco-2 cell monolayers formed on the surface of PLA nanofiber scaffolds also had better physiological function and prediction function in vitro. Overall, the present study indicated that the Transwell with the structurally and functionally biomimetic electrospun PLA nanofiber scaffold could be potentially developed as a promising in vitro intestinal model.

Prebiotic supplementation effect on Escherichia coli and Salmonella species associated with experimentally induced intestinal coccidiosis in rabbits

Background

Coccidian infection may enhance the proliferation of gut Enterobacteriaceae. Bacterial infections in rabbits can negatively affect the body condition and cause high mortality, especially at young ages. Therefore, the effect of prebiotic supplementation on the presence of Escherichia coli and Salmonella species in rabbits experimentally infected with intestinal coccidiosis was investigated.

Methods

Thirty male rabbits aged 35–40 days were divided into three equal groups. These groups were; prebiotic supplemented (PS), positive control (PC), and negative control (NC) groups. The prebiotic group was supplemented with 2 g/L of Bio-Mos^® until the end of the experiment. At day ten post prebiotic supplementation; the PS and PC groups were inoculated orally with 5.0 × 10⁴ sporulated oocysts of mixed species of rabbit Eimeria. The daily fecal examination was carried out from the day 4 post-infection (PI) until the day 8 PI. At day 5 and day 8 PI, 5 rabbits from each group (PS, PC, and NC) were humanely slaughtered and parts of intestinal tissue were collected for microbiological analysis.

Results

There was a significant decrease (P≤ 0.05) in the oocyst count in the PS group (25.12 × 10⁴ ± 10.36) when compared with the PC group (43.43 × 10⁴ ± 11.52) and this decrease was continued till the end of the experiment. Eleven E. coli isolates were detected in the collected samples with an overall prevalence of 24.4%. The highest prevalence of E. coli was in the PC group (13.33%) while the lowest one was in the PS group (4.44%). Meanwhile, four Salmonella serovars were isolated with an overall prevalence of 8.89%. The NC group showed one serovar (2.22%) and PC revealed three serovars (6.67%) while the prebiotic supplemented group didn’t show any salmonella isolate. Of E. coli isolates, five isolates (O78, O125, O152, O115 and O168) showed high resistance to florfenicol and neomycin (100%). Also, of salmonella serovars, thee serovars (Salmonella entrica subsp. enterica serovar Macclesfield, Salmonella entrica Subsp. enterica serovar Canada and Salmonella entrica Subsp. enterica serovar Kisangani) showed high resistance to sulphamazole, amoxicillin and flumequin (75%) while it was sensitive to levofloxacin and ciprofloxacine (75%). The bacterial colony in this study was the same results at days 5 and 8 PI.

Conclusion

The use of prebiotic as prophylaxis in this experiment significantly reduced the prevalence of E. coli and salmonella associated with the intestinal coccidiosis in rabbits.

Effect of Probiotics and Multi-Component Feed Additives on Microbiota, Gut Barrier and Immune Responses in Broiler Chickens During Subclinical Necrotic Enteritis

The withdrawal of antibiotic growth promoters from poultry feed has increased the risk of necrotic enteritis (NE) outbreaks. This study examined the effects of a probiotic (PROB) or probiotic/prebiotic/essential oil supplement (PPEO) during a subclinical NE challenge. On day (d) of hatch, 960 male broilers were randomized to four groups (8 pens/treatment, 30 birds/pen) including (1) negative control (NC): corn-soybean meal diet; (2) positive control (PC): NC + 20 g Virginiamycin/ton diet; (3) NC + 227 g PROB/ton diet; and (4) NC + 453 g PPEO/ton diet. One d after placement, birds were challenged by a coccidia vaccine to induce NE. Feed intake and body weights were measured on d 8 (NE onset) and end of each feeding period. On d 8, the small intestines of three birds/pen were examined for NE lesions. Jejunum samples and ileal mucosal scrapings from one bird/pen were respectively collected to measure mRNA abundance (d 8 and d 14) and profile the microbiota (d 8 and d 42). Data were analyzed in JMP or QIIME 2 and significance between treatments identified by LSD (P < 0.05). PROB and PPEO had significantly lower mortality (d 0–14) and NE lesion scores compared to NC. Feed conversion ratio was significantly lower in PC, PROB, and PPEO, while average daily gain was higher in PPEO and PC groups compared to NC from d 0–42. On d 8 and d 14, mRNA abundance of claudin-3 was higher in PPEO compared to NC. On d 14, compared to NC, mRNA abundance of sIgA and PGC-1α in PROB and PPEO were lower and higher, respectively. Compared to NC, PPEO increased mTOR abundance on d 14. On d 8, relative abundance of Clostridium sensu stricto 1, Ruminiclostridium9, Prevotellaceae, Prevotellaceae UCG-014, ASF356, and Muribaculaceae was higher in NC compared to PPEO and PROB, while Lactobacillus was lower in NC. Escherichia-Shigella had higher abundance in PC compared to PPEO and PROB. Collectively, these data indicate that during a subclinical naturally occurring NE, supplementation of PROB or PPEO supports performance and reduces intestinal lesions, potentially through modifying tight junction proteins, gut microbiota, immune responses, and cell metabolism.

The Bacillus cereus Food Infection as Multifactorial Process

The ubiquitous soil bacterium Bacillus cereus presents major challenges to food safety. It is responsible for two types of food poisoning, the emetic form due to food intoxication and the diarrheal form emerging from food infections with enteropathogenic strains, also known as toxico-infections, which are the subject of this review. The diarrheal type of food poisoning emerges after production of enterotoxins by viable bacteria in the human intestine. Basically, the manifestation of the disease is, however, the result of a multifactorial process, including B. cereus prevalence and survival in different foods, survival of the stomach passage, spore germination, motility, adhesion, and finally enterotoxin production in the intestine. Moreover, all of these processes are influenced by the consumed foodstuffs as well as the intestinal microbiota which have, therefore, to be considered for a reliable prediction of the hazardous potential of contaminated foods. Current knowledge regarding these single aspects is summarized in this review aiming for risk-oriented diagnostics for enteropathogenic B. cereus.

In vitro probiotic screening and evaluation of space-induced mutant Lactobacillus plantarum

Space mutation is an efficient tool in microbial breeding. The aim of the present study was to screen out space-induced mutants of Lactobacillus plantarum with potent probiotic properties. The wild-type Lactobacillus plantarum GS18 was subjected to 31 days and 18.5 hr of space flight, in which 13 isolates were selected for analysis. These mutants were assayed for milk fermentation performance, low pH resistance, bile salt tolerance, hydrophobicity, and antimicrobial activity. The 16S rDNA sequencing was applied to identify the stain and compare it with the wild type. Results showed that the isolate L. plantarum SS18-50 had the strongest probiotic properties with no mutation in 16S rRNA sequence compared to the wild type. Specifically, L. plantarum SS18-50 had good milk fermentation performance. The viscosity of fermented milk, acid tolerance, and bile salt tolerance were increased by approximately 10%, 8%, and 9%, respectively (p < .05). The antibacterial activity (Escherichia Coli, Salmonella Typhimurium, and Listeria Monocytogenes) was also increased significantly compared to the wild type (p < .05). This study indicates that L. plantarum SS18-50 has the great potential to serve as a probiotic for dairy products.

Effect of enzymatic treatment of citrus by-products on bacterial growth, adhesion and cytokine production by Caco-2 cells

Citrus by-products are inexpensive sources of polyphenols, important bioactive compounds with wide pharmaceutical and food applications. This study aimed to investigate the effect of enzymatic treatment of citrus by-products on the polyphenolic profile of extracts and assess the influence of extracts on the growth and adhesion of probiotics and foodborne pathogenic bacteria and on the inflammatory response of epithelial cells. Enzyme-assisted extraction altered the polyphenolic profile (as assessed by HPLC-DAD), increasing the content of aglycone flavanones (naringenin and hesperetin). Enzymatic extracts and aglycone flavanones exhibited higher antibacterial and prebiotic activities than non-enzymatic extracts and glycoside flavanones. However, a higher content of aglycones was not associated with higher anti-adhesion activity. Citrus extracts significantly (P ≤ 0.05) decreased the inflammatory response of Caco-2 cells to Salmonella Typhimurium adhesion. These results support the sustainable reuse of citrus agroindustrial wastes and indicate the potential of citrus extracts in preventing infection by foodborne pathogenic bacteria and inducing proliferation of probiotics in foods and the gut environment.

Helicobacter pylori: Perturbation and restoration of gut microbiome

Alternate remedies with natural products provides unlimited opportunities for new drug development. These can be either as pure compounds or as standardized set of compounds. The phytochemicals and secondary metabolites are in great demand for screening bioactive compounds and plays an important role towards drug development. Natural products have many advantages over to synthetic chemical drugs. Helicobacter pylori (H. pylori) a Gram-negative bacteria has been classified as Class I carcinogen by World Health Organization in 1994. Current treatment regimens for H. pylori is ‘triple therapy’ administrated for two weeks which includes a combination of two antibiotics like Amoxicillin and Clarithromycin and a proton pump inhibitor (PPI) like Lansoprazole, and for ‘quadruple therapy’ in addition to antibiotics and a PPI, Bismuth is used. Antibiotic resistance can be named as the main factor for failure of treatment of H. pylori infection. The need of the hour is to develop a herbal remedy that could combat the growth of H. pylori. Probiotics can also be used as ‘feasible’ tool for H. pylori infection management. Present review is an attempt to briefly discuss about the pathogenicity, genetic predisposition, perturbation of gut microbiota due to antibiotic treatment and restoration of healthy gut microbiota with phytochemicals and probiotics.

In vitro Evaluation of Antibacterial, Cytotoxic and Adherence Studies of Selected Commercial Probiotics

There is increasing scientific evidence and commercial interest for using probiotics for eliminating and handling of specific diseases. Probiotics can be evaluated for its role and performance against isolated pathogens from contaminating sources. The present work reports on invitro antimicrobial activity of commercial selected probiotics against pathogenic microbe Vibrio parahaemolyticus. The work also describes cytotoxic activities using MTT assay and adherence studies of selected probiotics. Results for the studies showed maximum zone of inhibition 13.66±0.46mm in probiotic enteroplus,12.33±0.93mm in lactobacillus (NCIM2056) and 10.66±0.93mm in Avant Bact. Cytotoxicity was expressed as IC50(µg/ml) values, observed on CaCO cell lines for different probiotics. Avant Bact showed a IC50 value of 104.7745, Lactobacillus (NCIM2056) a value of 58.13223 and Enteroplus a value of 50.09716. These values expressed different safety aspects of probiotics used for study. Finally the adherence study was done to check probiotic colonizing capacity. The probiotics showed varied adherence capacity against caco cell lines. Enteroplus has % adhesion of 10.25±0.74, Avant Bact. 7.25±0.82 and Lactobacillus (NCIM2056) 7.5±1.12. In conclusion antimicrobial results show importance of probiotics to be used against specific gastro intestinal diseases. Cytotoxicity determines safety aspects of probiotics and adherence study determines probiotic as a promising candidate for in vivo studies.

Barrier Protection and Recovery Effects of Gut Commensal Bacteria on Differentiated Intestinal Epithelial Cells In Vitro

Alterations in the gut microbiota composition play a crucial role in the pathogenesis of inflammatory bowel disease (IBD) as specific commensal bacterial species are underrepresented in the microbiota of IBD patients. In this study, we examined the therapeutic potential of three commensal bacterial species, Faecalibacterium prausnitzii (F. prausnitzii), Roseburia intestinalis (R. intestinalis) and Bacteroides faecis (B. faecis) in an in vitro model of intestinal inflammation, by using differentiated Caco-2 and HT29-MTX cells, stimulated with a pro-inflammatory cocktail consisting of interleukin-1β (IL-1β), tumor necrosis factor-α (TNFα), interferon-γ (IFNγ), and lipopolysaccharide (LPS). Results obtained in this work demonstrated that all three bacterial species are able to recover the impairment of the epithelial barrier function induced by the inflammatory stimulus, as determined by an amelioration of the transepithelial electrical resistance (TEER) and the paracellular permeability of the cell monolayer. Moreover, inflammatory stimulus increased claudin-2 expression and decreased occludin expression were improved in the cells treated with commensal bacteria. Furthermore, the commensals were able to counteract the increased release of interleukin-8 (IL-8) and monocyte chemoattractant protein-1 (MCP-1) induced by the inflammatory stimulus. These findings indicated that F. prausnitzii, R. intestinalis and B. faecis improve the epithelial barrier integrity and limit inflammatory responses.

Amaranth Meal and Environmental Carnobacterium maltaromaticum Probiotic Bacteria as Novel Stabilizers of the Microbiological Quality of Compound Fish Feeds for Aquaculture

Fish feed should be characterized by microbiological stability to guarantee the optimal health of farmed fish. The aim of this study was to determine the efficacy of amaranth meal (Amaranthus cruentus) and a highly active environmental strain of probiotic bacteria, Carnobacterium maltaromaticum, as novel supplements that stabilize the quantitative and qualitative composition of microbiota in compound fish feeds for aquaculture, regardless of storage temperature. The total viable counts of mesophilic bacteria at 28 °C (TVC 28 °C), hemolytic mesophilic bacteria (Hem 37 °C), Staphylococcus sp. bacteria, aerobic spore-forming bacteria (ASFB), sulfite-reducing anaerobic spore-forming Clostridium sp. bacteria, yeasts, and molds were analyzed in control feed (CF), in feed supplemented with amaranth meal (AF), and in feed supplemented with amaranth meal and C. maltaromaticum (ACF), stored at a temperature of 4 °C and 20 °C for 98 days. Amaranthus cruentus and C. maltaromaticum significantly reduced bacterial counts in fish feeds, regardless of the temperature and duration of storage. The antibacterial and antifungal effects of the tested additives were statistically significant (p ≤ 0.05). The studied novel supplements contribute to the microbiological safety of compound fish feeds. The tested additives could be recognized as the key ingredients of organic, environmentally friendly fish feeds, which guarantee the high quality of fish intended for human consumption.

In vitro studies of adhesion properties of six lactic acid bacteria isolated from the longevous population of China

Six lactic acid bacteria (LAB), isolated from the intestinal tract of the longevous population, were prominent for their strong bacteriostatic ability. In this study, the adhesion properties of the six strains were determined in vitro to explore their potential to be used as probiotics. The hydrophobicity and aggregation activity were firstly detected and were varied from 14.83% to 57.3% and 12.7% to 31%, respectively. Moreover, the adhesion activity to the intestinal crypt cells (IEC-6 cells) was proved to be varied from 5.4 to 21.7 bacteria numbers per cell. Furthermore, all the tested LAB samples could inhibit 3 Gram-positive and 3 Gram-negative indicator microorganisms to adhere to the IEC-6 cells. Meanwhile every sample was inclined to exclude rather than displace or compete to inhibit the indicator microorganisms to adhere to IEC-6 cells. Afterwards, the adhesion activities of the LAB were demonstrated to be highly affected by the surface proteins considering the treatments of heat, pepsin, trypsin and NaIO₄. The surface proteins (8–14 kDa) of every sample were isolated and proved to be helpful to regain more than 30% of the adhesion activity for the corresponding samples. This study will be beneficial to examine the characteristics of these strains especially L. casei g9 when used as probiotics in dairy food products.

Adhesion related activities of six lactic acid bacteria were detected. This study will be beneficial to examine the characteristics of these strains used as probiotics in dairy products.

Isolation, selection and evaluation of Bacillus spp. as potential multi-mode probiotics for poultry

Bacillus based probiotics are becoming relevant as alternatives to antibiotics used in poultry production and in other animal husbandry. This study describes the isolation of 48 Bacillus spp. candidates, from chickens and chicken environments, for use as potential probiotics in poultry production. These isolates, plus a further 18, were tested in a comprehensive in vitro screening regime that was specifically designed to select the best isolates that satisfied multiple modes of action desirable for commercial poultry probiotics. This screening programme involved the evaluation of the ability of the isolates to survive and grow in the limiting conditions of the chicken gastrointestinal tract. Only 11 of the isolates fulfilled these criteria; hence, they were further evaluated for the ability to adhere to epithelial cells, produce extracellular enzymes, and to demonstrate antagonistic activity against selected pathogens of significant importance in poultry production. Of these, a total of 6 isolates were selected, due to their all-round probiotic capability. Identification by 16S RNA sequencing confirmed these isolates as B. subtilis and B. velezensis, identities which are generally regarded as safe. The Bacillus isolates reported in our study exhibit strong all-inclusive probiotic effects and can potentially be formulated as a probiotic preparation for poultry production.

Limiting the pathogenesis of Salmonella Typhimurium with berry phenolic extracts and linoleic acid overproducing Lactobacillus casei

The growing threat of emergent multidrug-resistant enteric bacterial pathogens, and their adopted virulence properties are directing to find alternative antimicrobials and/or development of dietaries that can improve host gut health and/or defense. Recently, we found that modified Lactobacillus casei (Lc + CLA) with increased production of conjugated linoleic acid has antimicrobial and other beneficial properties. Further, prebiotic alike products such as berry pomace extracts (BPEs), increase the growth of probiotics and inhibit the growth of certain bacterial pathogens. In this study, we evaluated the antibacterial effect of genetically modified Lc + CLA along with BPEs against major enteric pathogen Salmonella enterica serovar Typhimurium (ST). In mixed culture condition, the growth of ST was significantly reduced in the presence of Lc + CLA and/or BPEs. Bacterial cell-free cultural supernatant (CFCS) collected from wild-type Lc or modified Lc + CLA strains also inhibited the growth and survival of ST, and those inhibitory effects were enhanced in the presence of BPEs. We also found that the interaction of the pathogen with cultured host (HD-11 and INT-407) cells were also altered in the presence of either Lc or Lc + CLA strain or their CFCSs significantly. Furthermore, the relative expression of genes related to ST virulence and physicochemical properties of ST was altered by the effect of CFCSs of either Lc or Lc + CLA. These findings indicate that a diet containing synbiotic, specifically linoleic acid, over-produced Lc + CLA and prebiotic product BPEs, might have the potential to be effective in controlling ST growth and pathogenesis.

Probiotics L. acidophilus and B. clausii Modulate Gut Microbiota in Th1- and Th2-Biased Mice to Ameliorate Salmonella Typhimurium-Induced Diarrhea

Gut microbiota play important role in maintaining health. Probiotics are believed to augment it further. We aimed at comparing effects of probiotics, Lactobacillus acidophilus (LA) and Bacillus clausii (BC) (a) on the gut microbiota abundance and diversity and (b) their contributions to control intestinal dysbiosis and inflammation in Th1- and Th2-biased mice following Salmonella infection. We report how could gut microbiota and the differential immune bias (Th1 or Th2) of the host regulate host responses when challenged with Salmonella typhimurium in the presence and absence of either of the probiotics. LA was found to be effective in ameliorating the microbial dysbiosis and inflammation caused by Salmonella infection, in Th1 (C57BL/6) and Th2 (BALB/c)-biased mouse. BC was able to ameliorate Salmonella-induced dysbiosis and inflammation in Th2 but not in Th1-biased mouse. These results may support probiotics LA as a treatment option in the case of Salmonella infection.

Techno-functional characterization of indigenous Lactobacillus isolates from the traditional fermented foods of Meghalaya, India

The rural tribal people of Meghalaya depend mostly on their ethnic fermented foods as a part of their regular diet and these fermented foods are considered to be a hub of healthy microorganisms. However, the efficacy of probiotic microorganisms is considered to be population-specific because of gut microflora variation in food habits and specific host-microbial interactions. Hence, a strong need for exploring novel indigenous microorganisms with rich probiotic potentiality is required. A few indigenous Lactobacillus isolates (from traditional fermented foods of Meghalaya) were studied extensively for its technological and probiotic attributes. The isolates could survive at pH 2–3 (L. fermentum K16 showed high cell count: pH 2–5.12 log CFU/ml; pH 3–5.76 log CFU/ml), against bile salts (L. fermentum K7 showed high cell count-5.36 log CFU/ml), gastric juices (pepsin and trypsin), and intestinal juice (pancreatin). The isolates showed α-galactosidase activity from 0.104-0.412 μM/ml and β-glucosidase activity ranging from 0.122-0.409 μM/ml. Exopolysaccharide production was in between 410 and 950 mg/L. Cell surface hydrophobicity was 71.57% (L. rhamnosus K4E) and auto-aggregation was 83% (L. fermentum K16) during the study. Highest proteolytic activity (0.671 nm) and cholesterol assimilation (52.57%) was exhibited by L. fermentum K16. The isolates showed high free radical scavenging activity by ABTS method up to 80.78% by isolate L. fermentum K7. Antibacterial activity and co-aggregation efficacy was also tested against B. cereus, E. faecalis, S. dysenteriae, S. aureus, E. coli, L. monocytogenes, S. typhi. These indigenous Lactobacillus isolates with high probiotic potentials could be exploited in the development of the traditional fermented foods of Meghalaya.

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Technological and probiotic attributes (in vitro) of eight indigenous Lactobacillus strains were studied.

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Lactobacillus strains were isolated from the traditional fermented foods of Meghalaya, India.

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L. rhamnosus K4E, L. fermentum K16, L. fermentum K7 and L. plantarum RD7 were considered predominant over the rest of the strains.

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The isolates could be employed for development of novel functional fermented foods.

Probiotics decrease the stress response and intestinal permeability of term neonates with low Apgar scores

To observe the effect of probiotics on the stress responses and intestinal permeability of term neonates with low Apgar scores, the present study retrospectively analyzed the clinical data of 78 term neonates (42 males and 36 females). In the control group (n=38), total parenteral nutrition and comprehensive treatment (anti-infection therapy) were provided. In the observation group (n=40), the neonates were administered Lactobacillus Complex Capsules in addition to the control group treatment. The corticotropin-releasing factor level was determined using ELISA; cortisol levels were determined using a radioimmunoprecipitation assay; D-lactate and diamine oxidase levels were determined using ultraviolet spectrometry; procalcitonin levels were determined using ECL; and C-reactive protein levels were determined using a protein analyzer. Following treatment, the levels of all parameters were lower in the observation group compared with the control group, and the differences were statistically significant (P<0.05). In the observation group, the daily milk intake was 16.57±2.58 ml, which was significantly higher than that of the control group (13.26±1.87 ml), while the length of hospital stay and total parenteral nutrition time, which were 12.31±2.02 and 6.21±1.26 days, respectively, in the observation group, were significantly shorter than those of the control group (14.86±2.58 and 8.86±1.78 days, respectively), and the differences were statistically significant (P<0.001). The results of the present study suggested that probiotics can ameliorate the stress response and intestinal permeability of term neonates with low Apgar scores, thereby, facilitating gastrointestinal function recovery.

Prophylactic and Therapeutic Efficacy of Prebiotic Supplementation against Intestinal Coccidiosis in Rabbits

Simple Summary

There are limitations for using chemical products in meat production. The use of prebiotics to control Eimeria infections in rabbits may be of value. Prebiotics as a prophylaxis resulted in diminishing adverse effects caused by Eimeria spp. through decreasing fecal oocyst counts, retaining body weight, and reducing the number of parasitic stages in the intestinal tissues when compared with the non-supplemented controls.

Abstract

This study was conducted to investigate the effect of prebiotic supplementation against intestinal coccidiosis in rabbits. Fifty male rabbits aged 35–60 days (1–1.5 kg) were divided into prophylactic and therapeutic experiments (five groups, 10 rabbits per group). Prophylactic experiment had prebiotic supplemented (PS-P), non-supplemented infected control (NI-P), and non-supplemented non-infected control (NN-P) groups. Ten days post-prebiotic supplementation (PPS), rabbits in groups PS-P and NI-P were infected orally with 5.0 × 10⁴ sporulated oocysts of mixed Eimeria species. However, therapeutic experiment had prebiotic supplemented (PS-T) and untreated infected (UI-T) groups of naturally infected rabbits with Eimeria species. A significant reduction in oocyst count per gram feces (OPG) (p ≤ 0.05) was reported in the PS-P (57.33 × 10³ ± 2.84) and NI-P (130.83 × 10³ ± 43.38) groups during the experiment. Additionally, rabbits in groups (PS-P, 970.33 ± 31.79 g and NI-P, 870.66 ± 6.66 g) showed weight loss after infection. However, a significant (p ≤ 0.05) decrease in OPG was observed at day seven PPS in the PS-T group (4 × 10³ ± 0.00) when compared with the UI-T group (32 × 10³ ± 7.54). Furthermore, the PS-T group had a higher body weight than rabbits in the UI-T group. Histopathological findings of the intestinal tissues (duodenum, jejunum, and ileum) showed that the counts of the endogenous stages were significantly higher in the NI-P and UI-T groups than in the prebiotic-supplemented groups (PS-P and PS-T). Supplementation of the prebiotic did not have any adverse effects on biochemical parameters, such as AST, ALT, creatinine, total protein, and total cholesterol. In conclusion, prebiotic supplementation can be used to minimize the adverse effects of intestinal coccidiosis in rabbits, which in turn limits body weight loss, especially for the prophylaxis of coccidial infection.

Evaluation of safety and probiotic properties of a strain of Enterococcus faecium isolated from chicken bile

Probiotics are important bacteria due to their benefit on human health. In this study, four strains of lactic acid bacteria from chicken bile were isolated and the strain with the best antimicrobial activity was selected for further identification and evaluation on its probiotic traits and safety. The strain was identified as Enterococcus faecium by biochemical characterization and 16S rDNA gene sequencing. The strain, named E. faecium MK-SQ-1, was tolerant to acid (pH 3.0), bile salts (up to 0.3%) or trypsin (up to 0.4%) for 3 h and it was able to survive from high temperature (up to 60 °C) for 15 min. This strain inhibited the growth of Salmonella enteritidis and Staphylococcus aureus intermediately. The genes responsible for virulence including asa1, cylA, efaA, esp, gelE and hyl were absent and the mice administrated orally with a very high dose (2 × 10⁹ CFU) of the strain daily for 35 days were not found abnormal. The strain enhanced the serum IgG level and phagocytic index of mice significantly by daily oral administration at a high dose (2 × 10⁸ CFU) for 21 days (p < 0.05). The strain did not have multi-antibiotic resistance and vancomycin resistance. Comprehensive evaluation showed E. faecium MK-SQ-1 could be a candidate as a probiotic strain used in human or animals.

Microbial Mechanistic Insights into the Role of Sweet Potato Vine on Improving Health in Chinese Meishan Gilt Model

Simple Summary

Sweet potato vine as a source of fiber had been used in China for many years. We investigated the effects of fresh sweet potato vine on intestinal and plasma metabolites as well as colon microbial composition in Chinese Meishan gilts. Results suggest that sweet potato vine promoted intestinal muscle development, decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations, and increased butyrate production as well as beneficial flora, thus improving gut health.

Abstract

This study explored the impact of fresh sweet potato vine on the growth as well as the metabolites and colon microbial composition in Chinese Meishan gilt. Twenty Meishan gilts (body weight 30 ± 0.18 kg, n = 10 per treatment) were randomly assigned to a control (CON) or sweet potato vine (SPV) supplementation diet treatment. Gilts were housed in individual stalls. In the SPV treatment, 2 kg fresh sweet potato vine was used instead of 0.18 kg basal diet which provided the same amount of digestive energy and crude protein with the exception of crude fiber (CON, 51.00 g/d vs. SPV, 73.94 g/d) in terms of dry matter intake. Gilts were slaughtered and samples were collected on day 19 after the third estrus cycle. The SPV treatment tended to increase slaughter weight of gilts (p = 0.07); it also increased (p < 0.05) gastrointestinal tract weight and intestinal muscle layer thickness. SPV treatment also decreased (p < 0.05) carcass yield and subcutaneous adipose tissue. The concentration of zonulin and endotoxin in plasma was decreased (p < 0.05) as the gilt consumed the SPV diet. Colonic fecal concentrations of endotoxin, lipocalin-2, and tumor necrosis factor-α (TNF-α) were decreased (p < 0.05), and interleukin-10 (IL-10) was increased (p < 0.05) in the SPV treatment. Butyric acid and acetate concentration in colonic content as well as acetate concentration in caecal content were increased (p < 0.05) in the SPV treatment. Furthermore, the expression of carnitine palmityl transferase (CPT-1) and peroxisome proliferator-activated receptor-α (PPAR-α) in gilt liver in SPV treatment was increased (p < 0.05) in comparison with CON treatment. Meanwhile, the composition of the colon microbes was also altered by SPV; representative changes included an increase in Lactobacillus, Bacteroides, Roseburia, and Lachnospira. These results indicate that gilt fed with sweet potato vine had decreased gut permeability, endotoxin and pro-inflammatory cytokines concentrations; colonic fecal microbiota was also changed, which may be further beneficial to the intestinal health of Chinese Meishan gilt.