Prebiotic inulin supplementation modulates the immune response and restores gut morphology in Giardia duodenalis-infected malnourished mice

Antigenotoxicity and Cytotoxic Potentials of Cell-Free Supernatants Derived from Saccharomyces cerevisiae var. boulardii on HT-29 Human Colon Cancer Cell Lines

Microbial-derived postbiotics are of interest recently due to their lower side effects than chemotherapy for cancer treatment and prevention. This study aimed to investigate the potential antigenotoxic and cytotoxic effects of cell-free-supernatant (CFS) postbiotics derived from Saccharomyces boulardii by applying SOS chromotest and MTT assay on HT-29 cell lines. Also, further cellular pathway-related assays such as cell cycle, DAPI, and annexin V-FITC/PI staining were performed. Real-time PCR was utilized to assess the expression levels of some genes involved in apoptosis. Based on the outcomes, the CFSs of S. boulardii showed significant antigenotoxic effects (20-60%, P < 0.05), decreased cell viability (with the significant IC50 values of 33.82, 22.68, and 27.67 µg/mL after 24, 48, and 72 h respectively), suppressed the initial (G0/G1) phase of the cell's division, influenced the nucleus of the treated cells, induced apoptosis, and increased the expression of Caspas3 and PTEN genes after 48 h, while the RelA and Bcl-XL genes indicated diminished expression in treated HT-29 cells. Consequently, CFS postbiotics of S. boulardii exhibited significant antigenotoxic and cytotoxic effects and induced apoptosis responses in HT-29 cancer cells. The results of this investigation lead us to recommend that the CFS postbiotics generated from Saccharomyces cerevisiae var. boulardii be taken into consideration as a potential anticancer agent or in the design of supplementary medications to treat and prevent colon cancers.

A shotgun metagenomic analysis of the fecal microbiome in humans infected with Giardia duodenalis

BACKGROUND

The mechanisms underlying the clinical outcome disparity during human infection with Giardia duodenalis are still unclear. In recent years, evidence has pointed to the roles of host factors as well as parasite's genetic heterogeneity as major contributing factors in the development of symptomatic human giardiasis. However, it remains contested as to how only a small fraction of individuals infected with G. duodenalis develop clinical gastrointestinal manifestations, whereas the majority of infected individuals remain asymptomatic. Here, we demonstrate that diversity in the fecal microbiome correlates with the clinical outcome of human giardiasis.

METHODS

The genetic heterogeneity of G. duodenalis clinical isolates from human subjects with asymptomatic and symptomatic giardiasis was determined using a multilocus analysis approach. We also assessed the genetic proximity of G. duodenalis isolates by constructing phylogenetic trees using the maximum likelihood. Total genomic DNA (gDNA) from fecal specimens was utilized to construct DNA libraries, followed by performing paired-end sequencing using the HiSeq X platform. The Kraken2-generated, filtered FASTQ files were assigned to microbial metabolic pathways and functions using HUMAnN 3.04 and the UniRef90 diamond annotated full reference database (version 201901b). Results from HUMAnN for each sample were evaluated for differences among the biological groups using the Kruskal-Wallis non-parametric test with a post hoc Dunn test.

RESULTS

We found that a total of 8/11 (72.73%) human subjects were infected with assemblage A (sub-assemblage AII) of G. duodenalis, whereas 3/11 (27.27%) human subjects in the current study were infected with assemblage B of the parasite. We also found that the parasite's genetic diversity was not associated with the clinical outcome of the infection. Further phylogenetic analysis based on the tpi and gdh loci indicated that those clinical isolates belonging to assemblage A of G. duodenalis subjects clustered compactly together in a monophyletic clade despite being isolated from human subjects with asymptomatic and symptomatic human giardiasis. Using a metagenomic shotgun sequencing approach, we observed that infected individuals with asymptomatic and symptomatic giardiasis represented distinctive microbial diversity profiles, and that both were distinguishable from the profiles of healthy volunteers.

CONCLUSIONS

These findings identify a potential association between host microbiome disparity with the development of clinical disease during human giardiasis, and may provide insights into the mechanisms by which the parasite induces pathological changes in the gut. These observations may also lead to the development of novel selective therapeutic targets for preventing human enteric microbial infections.

Ultrastructural changes and IgA modulatory effect of commercial prebiotic and probiotic in murine giardiasis

Giardiasis, a parasitic infection of the gastrointestinal tract, is prevalent worldwide. The integrity of the intestinal epithelial barrier plays an important defensive role in giardiasis, and as Oral supplementation with prebiotics and probiotics is known to reinforce the intestinal barrier in many gastrointestinal diseases, this study assessed the effects of prebiotic and probiotic supplementation in giardiasis and compared the results with those obtained after nitazoxanide therapy. Swiss albino male lab-bred mice (n = 50) were divided into three major groups; Group I (control group), i.e., negative (noninfected nontreated) and positive controls (infected nontreated); Group II (preventive group), in which mice were provided prebiotic, probiotic, or a combination for 7 days before of infection, and Group III (therapy group), in which mice were administered prebiotic, probiotic, combined supplements and nitazoxanide from day 12 post-infection. The assessment was achieved through Giardia cyst count, histopathological examination and ultrastructure study. Also, Serological and immunohistochemical parameters were done to evaluate the modulation of IgA levels. Oral supplementation with prebiotic and probiotic, either before or after infection (in preventive or therapy groups respectively) resulted in a significant reduction in Giardia cyst shedding. Remarkable histological and ultrastructure improvement in the intestinal changes, along with a significant increase in the serological and immunohistochemical IgA levels, were seen in mice provided combined supplements and nitazoxanide (in therapy group). Thus, our results indicate that combined prebiotic and probiotic supplementation has promising anti-Giardia activity and that it can restore intestinal structures and modulate IgA response, apart from providing synergistic effects when added to nitazoxanide.

A low-carbon high inulin diet improves intestinal mucosal barrier function and immunity against infectious diseases in goats

Introduction

Abrupt weaning is a major stressful event, contributing to intestinal abnormalities and immune system dysfunction in weaned kids. Inulin is a prebiotic fiber with many positive functions, including promoting intestinal fermentation and enhancing host immunity in monogastric animals. However, the effects of a high-inulin, energy-rich diet on ruminal fermentation characteristics, methane emission, growth performance, and immune systems of weaned kids have not been investigated.

Methods

A fully automated in vitro fermentation system was used to investigate ruminal fermentation characteristics and methane emission of a mixed substrate of inulin and fat powder (1.31: 1) in comparison with maize grain-based starter concentrate. During a 1-week adaptation and 4-week trial phase, 18 weaned kids (8.97 ± 0.19 kg) were randomly assigned to two groups, one with a conventional diet (83% maize grain; CON) and the other with a low-carbon, high-inulin diet (41.5% maize grain, 14.4% fat powder, 18.9% inulin; INU).

Results

In the in vitro rumen fermentation experiment, the total gas production was not different (p > 0.05); however, a lower (p < 0.05) methane production was observed for INU as compared to CON. The average daily gain and the ratio of feed intake and growth performance of kids fed with INU were higher (p < 0.05) than those fed with CON. Serum concentrations of alanine transaminase (ALT) and lactate dehydrogenase (LDH) were lower (p < 0.05), whereas the concentration of high-density lipoprotein (HDL) and cholesterol (CHOL) were higher (p < 0.05) in kids fed with the INU diet as compared CON. Dietary inulin significantly increased (p < 0.05) the secretion of immunoglobulins (IgA, IgG, and IgM) and inflammatory cytokines (IFN-γ and IL-10) in ileum tissue. Although no differences (p > 0.05) were observed in mRNA expression of tight junction markers, the INU diet tended to increase (p = 0.09) gene expression of ribosomal protein S6 kinase beta-1 (P70S6K) in the mammalian target of rapamycin (mTOR) pathway of longissimus dorsi muscle.

Conclusion

Our findings highlighted that a low-carbon high-inulin energy-rich diet could be used as a promising strategy to improve gut immunity and growth performance of weaned kids under abrupt weaning stress and reduce methane production.

Synergistic Effect of Polysaccharides from Chamomile Tea with Nitazoxanide Increases Treatment Efficacy against Giardia intestinalis

Giardia intestinalis (syn. G. lamblia, G. duodenalis) is a protozoa parasite that produces one of the most frequent waterborne causes of diarrhea worldwide. This protozoan infects most mammals, including humans, and colonizes the small intestine, adhering to intestinal cells. The mechanism by which G. intestinalis causes diarrhea is multifactorial, causing intestinal malabsorption. The treatment of giardiasis uses chemotherapeutic drugs such as nitroimidazoles, furazolidone, paromomycin, and benzimidazole compounds. However, they are toxic, refractory, and may generate resistance. To increase efficacy, a current treatment strategy is to combine these drugs with other compounds, such as polysaccharides. Several studies have shown that polysaccharides have gastroprotective effects. Polysaccharides are high-molecular weight polymers, and they differ in structure and functions, being widely extracted from vegetables and fruits. In the present study, we show that polysaccharides found in chamomile tea (called MRW), in contact with antiparasitic agents, potentially inhibit the adhesion of parasites to intestinal cells. Moreover, at 500 µg/mL, they act synergistically with nitazoxanide (NTZ), increasing its effectiveness and decreasing the drug dose needed for giardiasis treatment.

Assessment of the Effects of the Synbiotic Combination of Bifidobacterium longum subsp. infantis CECT 7210 and Oligofructose-Enriched Inulin Against Digestive Bacterial Infections in a Piglet Model

The use of bifidobacteria as probiotics has proven to be beneficial in gastroenteric infections. Furthermore, prebiotics such as inulin can enhance the survival and growth of these bacteria. Two trials were performed to evaluate the effects of the administration of Bifidobacterium longum subsp. infantis CECT 7210 and oligofructose-enriched inulin against Salmonella enterica serovar Typhimurium or enterotoxigenic Escherichia coli (ETEC) F4. A total of 72 (Salmonella trial) and 96 (ETEC F4 trial) weaned piglets were used in a 2 × 2 design (with or without synbiotic, inoculated or not with the pathogen). After adaptation, animals were orally inoculated. Performance and clinical signs were evaluated. On days 4 and 8 (Salmonella trial) and 3 and 7 (ETEC F4 trial) post-inoculation (PI), one animal per pen was euthanized. Blood, digestive content and tissue samples were collected and microbiological counts, fermentation products, serum inflammatory markers and ileum histomorphometry analysis were performed. Both challenges had an impact on faecal consistency (p < 0.001), including the faecal shedding of Salmonella and increased numbers of enterobacteria and coliforms. The synbiotic administration did not have any effect on pathogen loads but induced changes in the fermentation profile, such as increased valeric acid in both trials as well as decreased acetic acid, except for Salmonella-challenged animals. The effect on propionate varied among trials, increasing in challenged synbiotic-treated pigs and decreasing in non-challenged ones in the Salmonella trial (P interaction = 0.013), while the opposed occurred in the ETEC F4 trial (P interaction = 0.013). The administration of the synbiotic increased intraepithelial lymphocytes (IEL; p = 0.039) on day 8 PI in the Salmonella trial and a similar trend occurred in non-challenged pigs in the ETEC F4 trial (P interaction = 0.086). The results did not provide evidence of reduced pathogen load with the synbiotic, although a modulation in fermentative activity could be identified depending on the challenge. Consistent increases were found in IEL, suggesting that this synbiotic combination has some immunomodulatory properties.

Parasite-Probiotic Interactions in the Gut: Bacillus sp. and Enterococcus faecium Regulate Type-2 Inflammatory Responses and Modify the Gut Microbiota of Pigs During Helminth Infection

Dietary probiotics may enhance gut health by directly competing with pathogenic agents and through immunostimulatory effects. These properties are recognized in the context of bacterial and viral pathogens, but less is known about interactions with eukaryotic pathogens such as parasitic worms (helminths). In this study we investigated whether two probiotic mixtures (comprised of Bacillus amyloliquefaciens, B. subtilis, and Enterococcus faecium [BBE], or Lactobacillus rhamnosus LGG and Bifidobacterium animalis subspecies Lactis Bb12 [LB]) could modulate helminth infection kinetics as well as the gut microbiome and intestinal immune responses in pigs infected with the nodular worm Oesophagostomum dentatum. We observed that neither probiotic mixture influenced helminth infection levels. BBE, and to a lesser extent LB, changed the alpha- and beta-diversity indices of the colon and fecal microbiota, notably including an enrichment of fecal Bifidobacterium spp. by BBE. However, these effects were muted by concurrent O. dentatum infection. BBE (but not LB) significantly attenuated the O. dentatum-induced upregulation of genes involved in type-2 inflammation and restored normal lymphocyte ratios in the ileo-caecal lymph nodes that were altered by infection. Moreover, inflammatory cytokine release from blood mononuclear cells and intestinal lymphocytes was diminished by BBE. Collectively, our data suggest that selected probiotic mixtures can play a role in maintaining immune homeostasis during type 2-biased inflammation. In addition, potentially beneficial changes in the microbiome induced by dietary probiotics may be counteracted by helminths, highlighting the complex inter-relationships that potentially exist between probiotic bacteria and intestinal parasites.

Oligosaccharide equine feed supplement, Immulix, has minor impact on vaccine responses in mice

Several mammalian species are vaccinated in early life, but little is known about the effect of diet on vaccine response. Oligosaccharides are increasingly proposed as dietary supplement for young individuals due to their anti-inflammatory potential elicited through modulation of gut microbiota (GM). Also, diet, e.g. the size of the fat fraction, is known to modulate the GM. We tested if an oligosaccharide diet (Immulix) and/or increased dietary fat content affected antibody titers to a tetanus vaccine in 48 BALB/cJTac mice through GM modulation. Female mice had significantly higher IgG titers with higher variation compared to male mice. The effects of Immulix and/or increased fat content were minor. Immulix negatively affected IgG titers in male mice four weeks after secondary vaccination but upregulated Il1b gene expression in the spleen. Immulix had a downregulating effect on expression of Cd4 and Foxp3 in ileum only if the mice were fed the diet with increased fat. The diet with increased dietary fat increased Il1b but decreased Cd8a gene expression in the spleen. Immulix and diet affected GM composition significantly. Increased dietary fat content upregulated Lactobacillus animalis but downregulated an unclassified Prevotella spp. Immulix decreased Lactobacillales, Streptococcaceae and Prevotellaceae but increased Bacteroides. It is concluded that in spite of some minor influences on immune cell markers, cytokines and IgG titers Immulix feeding or increased dietary fat content did not have any biologically relevant effects on tetanus vaccine responses in this experiment in mice.

High-fat diet increases the severity of Giardia infection in association with low-grade inflammation and gut microbiota dysbiosis

Exogenous factors that may influence the pathophysiology of Giardia infection remain incompletely understood. We have investigated the role of dietary fat in the pathogenesis of Giardia infection. Male 3 to 4-week-old C57BL/6 mice were fed either a low fat (LF) or a high fat (HF) diet for 12 days and challenged with G. duodenalis. In infected animals, the trophozoite burden was higher in HF + Giardia mice compared to the LF + Giardia group at day 7 post infection. Fatty acids exerted direct pro-growth effects on Giardia trophozoites. Analysis of disease parameters showed that HF + Giardia mice exhibited more mucosal infiltration by inflammatory cells, decreased villus/crypt ratios, goblet cell hyperplasia, mucus disruption, increased gut motility, and elevated fecal water content compared with LF + Giardia. HF diet-dependent exacerbation of Giardia-induced goblet cell hyperplasia was associated with elevated Atoh1 and Muc2 gene expression. Gut microbiota analysis revealed that the HF diet alone induces a taxonomic shift. HF + Giardia mice exhibited microbiota dysbiosis characterized by an increase of Firmicutes and a decrease of Bacteroidetes and significant changes in α- and β-diversity metrics. Taken together, the findings suggest that a HF diet exacerbates the outcome of Giardia infection. The data demonstrate that elevated dietary fat represents an important exogenous factor promoting the pathophysiology of giardiasis.

Coronavirus disease–2019 and the intestinal tract: An overview

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection can progress to a severe respiratory and systemic disease named coronavirus disease–2019 (COVID-19). The most common symptoms are fever and respiratory discomfort. Nevertheless, gastrointestinal infections have been reported, with symptoms such as diarrhea, nausea, vomiting, abdominal pain, and lack of appetite. Importantly, SARS-CoV-2 can remain positive in fecal samples after nasopharyngeal clearance. After gastrointestinal SARS-CoV-2 infection and other viral gastrointestinal infections, some patients may develop alterations in the gastrointestinal microbiota. In addition, some COVID-19 patients may receive antibiotics, which may also disturb gastrointestinal homeostasis. In summary, the gastrointestinal system, gut microbiome, and gut-lung axis may represent an important role in the development, severity, and treatment of COVID-19. Therefore, in this review, we explore the current pieces of evidence of COVID-19 gastrointestinal manifestations, possible implications, and interventions.

Giardia spp. and the Gut Microbiota: Dangerous Liaisons

Alteration of the intestinal microbiome by enteropathogens is commonly associated with gastrointestinal diseases and disorders and has far-reaching consequences for overall health. Significant advances have been made in understanding the role of microbial dysbiosis during intestinal infections, including infection with the protozoan parasite Giardia duodenalis, one of the most prevalent gut protozoa. Altered species composition and diversity, functional changes in the commensal microbiota, and changes to intestinal bacterial biofilm structure have all been demonstrated during the course of Giardia infection and have been implicated in Giardia pathogenesis. Conversely, the gut microbiota has been found to regulate parasite colonization and establishment and plays a critical role in immune modulation during mono and polymicrobial infections. These disruptions to the commensal microbiome may contribute to a number of acute, chronic, and post-infectious clinical manifestations of giardiasis and may account for variations in disease presentation within and between infected populations. This review discusses recent advances in characterizing Giardia-induced bacterial dysbiosis in the gut and the roles of dysbiosis in Giardia pathogenesis.

Effects of Bifidobacterium longum Subsp. infantis CECT 7210 and Lactobacillus rhamnosus HN001, Combined or Not With Oligofructose-Enriched Inulin, on Weaned Pigs Orally Challenged With Salmonella Typhimurium

Salmonella is a common causative agent of enteric disease and is developing mechanisms of resistance to antimicrobials. Probiotics, such as bifidobacteria and lactobacilli, and prebiotic fibers are a potential alternative to counteract this pathogen as they have demonstrated effectiveness in preventing its adhesion, reducing intestinal damage, and enhancing the host immune system. Furthermore, the benefits are expected to be potentiated when these compounds are administered together. A trial was performed to evaluate the efficacy of two probiotic strains (Bifidobacterium longum subsp. infantis CECT 7210 (Laboratorios Ordesa S.L.) and Lactobacillus rhamnosus HN001, combined or not with a prebiotic containing oligofructose-enriched inulin, against Salmonella Typhimurium. Ninety-six piglets (28 days old) were distributed into 32 pens assigned to 5 treatments: one non-challenged (control diet, CTR+) and four challenged: control diet (CTR−) or supplemented with probiotics (>3 × 10¹⁰ cfu/kg each strain, PRO), prebiotic (5%, PRE), or their combination (SYN). After 1 week of adaptation, animals were orally challenged with Salmonella Typhimurium. Feed intake, weight, and clinical signs were recorded. On days 4 and 8 post-inoculation (PI), one animal per pen was euthanized, and samples from blood, digestive content, and ileal tissues were collected to determine Salmonella counts, fermentation products, ileal histomorphology, and serum TNF-α and Pig-MAP concentrations. The effect of the oral challenge was evidenced by animal performance, fecal consistency, and intestinal architecture. Regarding the experimental treatments, animals belonging to the PRO group experienced a faster clearance of the pathogen, with more pigs being negative to its excretion at the end of the study and recovering the impaired ileal villi/crypt ratio more rapidly. Animals receiving the PRE diet showed a lower intestinal colonization by Salmonella, with no countable levels (<3 cfu/g) in any of the analyzed samples, and an augmented immune response suggested by serum Pig-MAP concentrations. Treatments including the prebiotic (PRE and SYN) showed similar changes in the fermentation pattern, with an increase in the molar percentage of valeric acid concentration in the colon. The SYN group, however, did not show any of the outcomes registered for PRO and PRE in Salmonella colonization or in immunity markers, suggesting the lack of synbiotic action in this animal model. Further research is needed to better understand the complex mechanisms behind these effects.

Synergetic responses of intestinal microbiota and epithelium to dietary inulin supplementation in pigs

PURPOSE

Inulin is a soluble dietary fiber that has been implicated in regulating the intestinal health. Here, we describe a synergetic response of intestinal microbiota and epithelial functions to increased intake of inulin in a porcine model.

METHODS

Twenty growing-pigs were randomly allocated to two groups (n = 10) and fed with a basal diet (BD) or BD containing 0.5% inulin (INU) for 21 days.

RESULTS

We show that INU supplementation not only elevated villus height and the abundance of zonula occludens-1 (ZO-1), but also increased acetate and butyrate concentrations in cecum (P < 0.05). Moreover, INU decreased IL-6 and TNFα secretion, and reduced intestinal epithelial cell apoptosis in ileum and cecum (P < 0.05). Interestingly, we observed an elevated 16S rRNA gene copies in cecum after INU ingestion (P < 0.05). INU had no influence on overall diversity, but acutely altered the abundance of specific bacteria. INU decreased the abundance of phylum Proteobacteria in ileum, but increased the phylum Bacteroidetes in the ileum and cecum (P < 0.05). INU significantly elevated the Lactobacillus spp. and Bacteroides spp. in the ileum and cecum, respectively. Importantly, INU elevated the expression levels of GPR43, GLP-2, and ZO-1, but decreased the expression levels of histone deacetylase 1 (HDAC1) and TNFα in the ileum and cecum mucosa (P < 0.05). Moreover, INU also elevated the expression levels of GPR109A and angiopoietin-4 (ANG-4) in the cecum mucosa (P < 0.05).

CONCLUSIONS

This study indicated how the intestinal microbiome and epithelium adapt to inulin ingestion, and furthered our understanding of the mechanisms behind the dietary fiber-modulated intestinal microbiota and health.

Fermentable Dietary Fiber Promotes Helminth Infection and Exacerbates Host Inflammatory Responses

Fermentable dietary fibers promote the growth of beneficial bacteria, can enhance mucosal barrier integrity, and reduce chronic inflammation. However, effects on intestinal type 2 immune function remain unclear. In this study, we used the murine whipworm Trichuris muris to investigate the effect of the fermentable fiber inulin on host responses to infection regimes that promote distinct Th1 and Th2 responses in C57BL/6 mice. In uninfected mice, dietary inulin stimulated the growth of beneficial bacteria, such as Bifidobacterium (Actinobacteria) and Akkermansia (Verrucomicrobia). Despite this, inulin prevented worm expulsion in normally resistant mice, instead resulting in chronic infection, whereas mice fed an equivalent amount of nonfermentable fiber (cellulose) expelled worms normally. Lack of expulsion in the mice fed inulin was accompanied by a significantly Th1-skewed immune profile characterized by increased T-bet⁺ T cells and IFN-γ production in mesenteric lymph nodes, increased expression of Ido1 in the cecum, and a complete absence of mast cell and IgE production. Furthermore, the combination of dietary inulin and high-dose T. muris infection caused marked dysbiosis, with expansion of the Firmicutes and Proteobacteria phyla, near elimination of Bacteroidetes, and marked reductions in cecal short-chain fatty acids. Neutralization of IFN-γ during infection abrogated Ido1 expression and was sufficient to restore IgE production and worm expulsion in inulin-fed mice. Our results indicate that, whereas inulin promoted gut health in otherwise healthy mice, during T. muris infection, it exacerbated inflammatory responses and dysbiosis. Thus, the positive effects of fermentable fiber on gut inflammation appear to be context dependent, revealing a novel interaction between diet and infection.

Effect of Dietary Inulin Supplementation on Growth Performance, Carcass Traits, and Meat Quality in Growing-Finishing Pigs

Inulin is one of the commercially feasible dietary fibers that has been implicated in regulating the gut health and metabolism of animals. This experiment was conducted to investigate the effect of dietary inulin supplementation on growth performance and meat quality in growing-finishing pigs. Thirty-six Duroc × Landrace × Yorkshire White growing barrows (22.0 ± 1.0 kg) were randomly allocated to two dietary treatments consisting of a basal control diet (CON) or basal diet supplemented with 0.5% inulin (INU). Results showed that inulin supplementation tended to increase the average daily gain (ADG) at the fattening stage (0.05 < p < 0.10). Inulin significantly increased the dressing percentage (p < 0.05) and tended to increase the loin-eye area. The serum concentrations of insulin and IGF-I were significantly higher (p < 0.05) in the INU group than in the CON group. Moreover, inulin supplementation significantly elevated the expression level of myosin heavy chain II b (MyHC IIb) in the longissimus dorsi (p < 0.05). Inulin significantly upregulated the expression of mammalian rapamycin target protein (mTOR) but decreased (p < 0.05) the expression level of muscle-specific ubiquitin ligase MuRF-1. These results show the beneficial effect of inulin supplementation on the growth performance and carcass traits in growing-finishing pigs, and will also facilitate the application of inulin in swine production.

Deletion of the Casp8 gene in mice results in ileocolitis, gut barrier dysfunction, and malassimilation, which can be partially attenuated by inulin or sodium butyrate

Genetically modified mice have been successfully used as models for inflammatory bowel diseases; however, dietary effects were poorly examined. Here, we studied the impact of particular nutrients and supplements on gut functions related to the knockout of the epithelial caspase-8 gene. Caspase-8 knockout (Casp8^∆IEC) and control (Casp8^fl) mice were fed for 4 wk a control diet (CD) enriched with 10% inulin (CD-Inu) or 5% sodium butyrate (CD-But) while having free access to plain water or water supplemented with 30% fructose (+F). Body weight changes, intestinal inflammation, and selected markers for barrier function and of liver steatosis were assessed. Casp8^∆IEC mice developed ileocolitis accompanied by changes in intestinal barrier morphology and reduced expression of barrier-related genes such as mucin-2 (Muc2) and defensins in the ileum and Muc2 in the colon. Casp8^∆IEC mice fed a CD also showed impaired body weight gain compared with Casp8^fl mice, which was even more pronounced in mice receiving water supplemented with fructose. Furthermore, we observed a marked liver steatosis and inflammation in some but not all Casp8^∆IEC mice under a CD, which was on average similar to that observed in control mice under a fructose-rich diet. Hepatic lipid accumulation, as well as markers of ileal barrier function, but not intestinal pathohistology or body weight loss, were attenuated by diets enriched with inulin or butyrate, especially in the absence of fructose supplementation. Our data show that ileocolitis, barrier dysfunction, and malassimilation in Caspase-8 knockout mice can be partially attenuated by oral inulin or butyrate supplementation.NEW & NOTEWORTHY Genetic mouse models for ileocolitis are important to understand inflammatory bowel disease in humans. We examined dietetic factors that might aggravate or attenuate ileocolitis and related pathologies in such a model. Deletion of the caspase-8 gene results not only in ileocolitis but also in gut barrier dysfunction, liver steatosis, and malassimilation, which can be partially attenuated by oral inulin or sodium butyrate. Our data indicate that diet modifications can contribute to disease variability and therapy.

Animal Models of Undernutrition and Enteropathy as Tools for Assessment of Nutritional Intervention

: Undernutrition is a major public health problem leading to 1 in 5 of all deaths in children under 5 years. Undernutrition leads to growth stunting and/or wasting and is often associated with environmental enteric dysfunction (EED). EED mechanisms leading to growth failure include intestinal hyperpermeability, villus blunting, malabsorption and gut inflammation. As non-invasive methods for investigating gut function in undernourished children are limited, pre-clinical models are relevant to elucidating the pathophysiological processes involved in undernutrition and EED, and to identifying novel therapeutic strategies. In many published models, undernutrition was induced using protein or micronutrient deficient diets, but these experimental models were not associated with EED. Enteropathy models mainly used gastrointestinal injury triggers. These models are presented in this review. We found only a few studies investigating the combination of undernutrition and enteropathy. This highlights the need for further developments to establish an experimental model reproducing the impact of undernutrition and enteropathy on growth, intestinal hyperpermeability and inflammation, that could be suitable for preclinical evaluation of innovative therapeutic intervention.

Prophylactic Potential of Synbiotic (Lactobacillus casei and Inulin) in Malnourished Murine Giardiasis: an Immunological and Ultrastructural Study

Giardiasis is a re-emerging infectious disease with outbreaks reported globally specially in children and malnourished individuals leading to malabsorption, growth retardation, and severe diarrhea. Thus, in the present study, prophylactic administration of synbiotic as the functional food was used to assess its antigiardial potential in malnourished murine giardiasis. Interestingly, prior administration of synbiotic (Lactobacillus casei + inulin) even to malnourished-Giardia-infected mice led to increased body mass, small intestine mass, lactobacilli counts, and reduced severity of giardiasis as evident by decreased cyst and trophozoite counts. Synbiotic therapy further boosted the innate and acquired immune response resulting into increase in nitric oxide, antigiardial secretory IgA and IgG antibody levels along with IL-6 and IL-10 cytokines, and decreased levels of inflammatory TNF-α cytokine in both serum and intestinal fluid in malnourished-synbiotic-Giardia-infected mice compared with malnourished-Giardia-infected mice. More specifically, histopathological and scanning electron microscopy analysis of the small intestine also confirmed the modulatory potentials of synbiotic in malnourished-synbiotic-Giardia mice which had less cellular and mucosal damage compared with severely damaged, mummified, and blunted villi in malnourished-Giardia-infected mice. Taken together, this is the first experimental study to report that prior supplementation of synbiotic restored the gut morphology and improved the immune status of the malnourished-Giardia-infected mice, and could be considered as the prophylactic adjunct therapy for malnourished individuals.

Antigenotoxicity and Cytotoxic Potentials of Metabiotics Extracted from Isolated Probiotic, Lactobacillus rhamnosus MD 14 on Caco-2 and HT-29 Human Colon Cancer Cells

Probiotics, the beneficial bacteria produce active metabolites which could probably mimic their anticancer effect and prevent the risk associated with live bacteria. Thus, the study was designed to isolate effective lactic acid bacteria (LAB) and monitor anticancerous potential of their metabiotic extracts. Probiotics were isolated from different sources and their cell free supernatants (CFS) were screened for antigenotoxic and cytotoxic potentials using SOS Chromo Test and MTT assay on Caco-2 and HT-29 cells. Organic extracts of CFS were prepared and dissolved in different solvents. The isolate with most effective metabiotic extract in terms of cytotoxicity was classified for probiotic and phylogenetic characters and the metabiotic extract was characterized physiochemically. Among 60 isolated LAB, CFS of only 10 isolates showed antigenotoxicity more than 30% and four exhibited 70-80% cytotoxicity. Further, organic extracts of these four CFS dissolved in carboxymethyl cellulose showed 80-90% cytotoxicity. Interestingly, the most effective isolate was found to possess probiotic attributes and phylogenetic characterization revealed it to be Lactobacillus rhamnosus MD 14. Physiochemical characterization of its metabiotic extract indicated the presence of heat sensitive organic acids and proteins. To conclude, metabiotics produced by isolated probiotic L. rhamnosus MD 14 exhibited both antigenotoxic and cytotoxic potential against colon cancer.

You are what you eat: diet, health and the gut microbiota

Since the renaissance of microbiome research in the past decade, much insight has accumulated in comprehending forces shaping the architecture and functionality of resident microorganisms in the human gut. Of the multiple host-endogenous and host-exogenous factors involved, diet emerges as a pivotal determinant of gut microbiota community structure and function. By introducing dietary signals into the nexus between the host and its microbiota, nutrition sustains homeostasis or contributes to disease susceptibility. Herein, we summarize major concepts related to the effect of dietary constituents on the gut microbiota, highlighting chief principles in the diet-microbiota crosstalk. We then discuss the health benefits and detrimental consequences that the interactions between dietary and microbial factors elicit in the host. Finally, we present the promises and challenges that arise when seeking to incorporate microbiome data in dietary planning and portray the anticipated revolution that the field of nutrition is facing upon adopting these novel concepts.

Effects of inulin supplementation to piglets in the suckling period on growth performance, postileal microbial and immunological traits in the suckling period and three weeks after weaning

The aim of this study was to investigate the effect of inulin (IN) supplementation to suckling piglets at and 3 weeks post-weaning. A total of 72 newborn piglets were used. Twenty-four piglets per group received different amounts of IN during the suckling period: (a) CON: no IN; (b) IN-0.5: 0.5 g IN/d on the 1st week, 1 g IN/d on the 2nd week, 1.5 g IN/d on the 3rd week and 2 g IN/d on the 4th week, or (c) IN-0.75: 0.75 g IN/d on the 1st week, 1.5 g IN/d on the 2nd week, 2.25 g IN/d on the 3rd week and 3 g IN/d on the 4th week. Starting at 28 d of age, piglets were weaned and received a post-weaning diet without inulin during the following 3 weeks. At both 28 d and 49 d of age, piglets were euthanised for sampling. Piglets of group IN-0.5 had the highest body weight starting from the 3rd week (p < 0.05), concomitant with the highest villus height and the ratio of villus height/crypt depth in the jejunum and ileum on both sampling days (p < 0.05). At 28 d of age, an increased concentration of propionate, iso-butyrate or total short chain fatty acids was observed between treatment IN-0.5 and the other groups in the caecum or colon (p < 0.05). Moreover, the relative abundance of Escherichia coli (p = 0.05) and Enterobacteriaceae (p = 0.01) in colonic digesta were reduced in IN-0.5-treated piglets, and in both IN-supplemented groups, colonic interleukin-8, tumor necrosis factor-α and toll-like receptor-4 mRNA abundance were decreased compared to the CON group (p < 0.05). However, at 49 d of age, most of these differences disappeared. In conclusion, treatment IN-0.5 improved during the suckling period of piglets development of intestine, but these beneficial effects were not lasting after weaning, when IN supplementation was terminated. Treatment IN-0.75, however, did not display a prebiotic effect.

Effects of Soluble Corn Fiber Alone or in Synbiotic Combination with Lactobacillus rhamnosus GG and the Pilus-Deficient Derivative GG-PB12 on Fecal Microbiota, Metabolism, and Markers of Immune Function: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study in Healthy Elderly (Saimes Study)

Background

The aging process leads to a potential decline in immune function and adversely affects the gut microbiota. To date, many in vitro and in vivo studies focused on the application of synbiotics (prebiotics combined with probiotics) as a promising dietary approach to affect gut microbiota composition and improved functioning of the immune system. However, studies using synbiotic preparations often have the limitation that it remains unclear whether any effect observed is a result of the prebiotic or probiotic or a synergistic effect of the combined supplement.

Objectives

We investigated the effects of a probiotic Lactobacillus rhamnosus GG and pilus-deficient L. rhamnosus GG-PB12 combined with Promitor™ Soluble Corn Fiber (SCF, a candidate prebiotic) on fecal microbiota, metabolism, immunity, and blood lipids in healthy elderly persons. A prospective, double-blind, placebo controlled, randomized, single-centered, crossover study in 40 healthy elderly subjects (aged 60–80 years) was carried out. Volunteers were randomized to consume either probiotic and prebiotic as synbiotic, prebiotic or placebo (maltodextrin) during 3 weeks. Three-week washout periods separated all the treatments. We assessed effects upon blood lipids, glucose, cytokines, natural killer (NK) cell activity, phenotype, and intestinal microbiota composition. SCF decreased IL-6, which was not observed with the synbiotics.

Results

Consumption of L. rhamnosus GG combined with SCF increased NK cell activity compared to baseline in females and the older group. In the fecal microbiota analyses, the strongest community shifts were due to L. rhamnosus GG combined with SCF and SCF treatments. L. rhamnosus GG combined with SCF and L. rhamnosus GG-PB12 combined with SCF significantly increased the genus Parabacteroides. L. rhamnosus GG combined with SCF and SCF increased concentrations of Ruminococcaceae Incertae Sedis. Oscillospira and Desulfovibrio slightly decreased in the L. rhamnosus GG combined with SCF group, whereas Desulfovibrio decreased also in the L. rhamnosus GG-PB12 combined with SCF group. L. rhamnosus GG combined with SCF reduced total cholesterol and LDL-cholesterol in volunteers with initially elevated concentrations. C-reactive protein significantly decreased during L. rhamnosus GG-PB12 combined with SCF intervention compared to baseline.

Conclusion

In conclusion, the synbiotic combination of L. rhamnosus GG with SCF showed a tendency to promote innate immunity by increasing NK cell activity in elderly women and in 70 to 80-year-old volunteers and decreased TC and LDL-c in hypercholesterolemic patients. In addition, L. rhamnosus GG-PB12 combined with SCF demonstrated an increase in NK cell activity compared to SCF alone in older volunteers. We also found significant positive effects on the immune response, evidenced by a decrease of the pro-inflammatory cytokine IL-6. Therefore, dietary intervention with L. rhamnosus GG combined with SCF could be of importance in elderly as an attractive option for enhancement of both the microbial and immune systems.