The short-chain fatty acid uptake fluxes by mice on a guar gum supplemented diet associate with amelioration of major biomarkers of the metabolic syndrome

Studies with dietary supplementation of various types of fibers have shown beneficial effects on symptoms of the metabolic syndrome. Short-chain fatty acids (SCFAs), the main products of intestinal bacterial fermentation of dietary fiber, have been suggested to play a key role. Whether the concentration of SCFAs or their metabolism drives these beneficial effects is not yet clear. In this study we investigated the SCFA concentrations and in vivo host uptake fluxes in the absence or presence of the dietary fiber guar gum. C57Bl/6J mice were fed a high-fat diet supplemented with 0%, 5%, 7.5% or 10% of the fiber guar gum. To determine the effect on SCFA metabolism, C-13-labeled acetate, propionate or butyrate were infused into the cecum of mice for 6 h and the isotopic enrichment of cecal SCFAs was measured. The in vivo production, uptake and bacterial interconversion of acetate, propionate and butyrate were calculated by combining the data from the three infusion experiments in a single steady-state isotope model. Guar gum treatment decreased markers of the metabolic syndrome (body weight, adipose weight, triglycerides, glucose and insulin levels and HOMA-IR) in a dose-dependent manner. In addition, hepatic mRNA expression of genes involved in gluconeogenesis and fatty acid synthesis decreased dose-dependently by guar gum treatment. Cecal SCFA concentrations were increased compared to the control group, but no differences were observed between the different guar gum doses. Thus, no significant correlation was found between cecal SCFA concentrations and metabolic markers. In contrast, in vivo SCFA uptake fluxes by the host correlated linearly with metabolic markers. We argue that in vivo SCFA fluxes, and not concentrations, govern the protection from the metabolic syndrome by dietary fibers

Giant cecal diverticulum in a child

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Integrating Multiple Analytical Datasets to Compare Metabolite Profiles of Mouse Colonic-Cecal Contents and Feces.

The pattern of metabolites produced by the gut microbiome comprises a phenotype indicative of the means by which that microbiome affects the gut. We characterized that phenotype in mice by conducting metabolomic analyses of the colonic-cecal contents, comparing that to the metabolite patterns of feces in order to determine the suitability of fecal specimens as proxies for assessing the metabolic impact of the gut microbiome. We detected a total of 270 low molecular weight metabolites in colonic-cecal contents and feces by gas chromatograph, time-of-flight mass spectrometry (GC-TOF) and ultra-high performance liquid chromatography, quadrapole time-of-flight mass spectrometry (UPLC-Q-TOF). Of that number, 251 (93%) were present in both types of specimen, representing almost all known biochemical pathways related to the amino acid, carbohydrate, energy, lipid, membrane transport, nucleotide, genetic information processing, and cancer-related metabolism. A total of 115 metabolites differed significantly in relative abundance between both colonic-cecal contents and feces. These data comprise the first characterization of relationships among metabolites present in the colonic-cecal contents and feces in a healthy mouse model, and shows that feces can be a useful proxy for assessing the pattern of metabolites to which the colonic mucosum is exposed

Evaluation of the Efficacy and Safety of a Marine-Derived Bacillus Strain for Use as an In-Feed Probiotic for Newly Weaned Pigs

peer-reviewedForty eight individual pigs (8.7±0.26 kg) weaned at 28±1 d of age were used in a 22-d study to evaluate the effect of oral administration of a Bacillus pumilus spore suspension on growth performance and health indicators. Treatments (n = 16) were: (1) non-medicated diet; (2) medicated diet with apramycin (200 mg/kg) and pharmacological levels of zinc oxide (2,500 mg zinc/kg) and (3) B. pumilus diet (non-medicated diet + 1010 spores/day B. pumilus). Final body weight and average daily gain tended to be lower (P = 0.07) and feed conversion ratio was worsened (P<0.05) for the medicated treatment compared to the B. pumilus treatment. Ileal E. coli counts were lower for the B. pumilus and medicated treatments compared to the non-medicated treatment (P<0.05), perhaps as a result of increased ileal propionic acid concentrations (P<0.001). However, the medicated treatment reduced fecal (P<0.001) and cecal (P<0.05) Lactobacillus counts and tended to reduce the total cecal short chain fatty acid (SCFA) concentration (P = 0.10). Liver weights were lighter and concentrations of liver enzymes higher (P<0.05) in pigs on the medicated treatment compared to those on the non-medicated or B. pumilus treatments. Pigs on the B. pumilus treatment had lower overall lymphocyte and higher granulocyte percentages (P<0.001) and higher numbers of jejunal goblet cells (P<0.01) than pigs on either of the other two treatments or the non-medicated treatment, respectively. However, histopathological examination of the small intestine, kidneys and liver revealed no abnormalities. Overall, the B. pumilus treatment decreased ileal E. coli counts in a manner similar to the medicated treatment but without the adverse effects on growth performance, Lactobacillus counts, cecal SCFA concentration and possible liver toxicity experienced with the medicated treatment.The study was funded by the Higher Education Authority/Institutes of Technology Ireland Technological Sector Research Strand III Programme

Reducing Campylobacter jejuni colonization in broiler chickens by in-feed supplementation with hyperimmune egg yolk antibodies

Campylobacter infections sourced mainly to poultry products, are the most important bacterial foodborne zoonoses worldwide. No effective measures to control these infections in broiler production exist to date. Here, we used passive immunization with hyperimmune egg yolks to confer broad protection of broilers against Campylobacter infection. Two novel vaccines, a bacterin of thirteen Campylobacter jejuni (C. jejuni) and C. coli strains and a subunit vaccine of six immunodominant Campylobacter antigens, were used for the immunization of layers, resulting in high and prolonged levels of specific immunoglobulinY (IgY) in the hens' yolks. In the first in vivo trial, yolks (sham, bacterin or subunit vaccine derived) were administered prophylactically in the broiler feed. Both the bacterin and subunit vaccine-induced IgY significantly reduced the number of Campylobacter-colonized broilers. In the second in vivo trial, the yolks were administered therapeutically during three days before euthanasia. The bacterin IgY resulted in a significant decrease in C. jejuni counts per infected bird. The hyperimmune yolks showed strong reactivity to a broad representation of C. jejuni and C. coli clonal complexes. These results indicate that passive immunization with hyperimmune yolks, especially bacterin derived, offers possibilities to control Campylobacter colonization in poultry

Streptomycin-induced inflammation enhances Escherichia coli gut colonization through nitrate respiration.

UnlabelledTreatment with streptomycin enhances the growth of human commensal Escherichia coli isolates in the mouse intestine, suggesting that the resident microbial community (microbiota) can inhibit the growth of invading microbes, a phenomenon known as "colonization resistance." However, the precise mechanisms by which streptomycin treatment lowers colonization resistance remain obscure. Here we show that streptomycin treatment rendered mice more susceptible to the development of chemically induced colitis, raising the possibility that the antibiotic might lower colonization resistance by changing mucosal immune responses rather than by preventing microbe-microbe interactions. Investigation of the underlying mechanism revealed a mild inflammatory infiltrate in the cecal mucosa of streptomycin-treated mice, which was accompanied by elevated expression of Nos2, the gene that encodes inducible nitric oxide synthase. In turn, this inflammatory response enhanced the luminal growth of E. coli by nitrate respiration in a Nos2-dependent fashion. These data identify low-level intestinal inflammation as one of the factors responsible for the loss of resistance to E. coli colonization after streptomycin treatment.ImportanceOur intestine is host to a complex microbial community that confers benefits by educating the immune system and providing niche protection. Perturbation of intestinal communities by streptomycin treatment lowers "colonization resistance" through unknown mechanisms. Here we show that streptomycin increases the inflammatory tone of the intestinal mucosa, thereby making the bowel more susceptible to dextran sulfate sodium treatment and boosting the Nos2-dependent growth of commensal Escherichia coli by nitrate respiration. These data point to the generation of alternative electron acceptors as a by-product of the inflammatory host response as an important factor responsible for lowering resistance to colonization by facultative anaerobic bacteria such as E. coli

Research note : lyophilization of hyperimmune egg yolk : effect on antibody titer and protection of broilers against Campylobacter colonization

Oral administration of antibodies is a promising strategy against various infectious diseases. Previously, it was demonstrated that passive immunization by providing hyperimmune egg yolk through the feed reduces Campylobacter jejuni colonization in broilers. Campylobacteriosis is the most commonly reported bacterial foodborne zoonosis worldwide, and poultry products are the number one origin of these bacteria for human infection. To date, no effective control measures exist to limit Campylobacter colonization in the chicken's intestinal tract. Here, the effect of lyophilization of hyperimmune egg yolk on protection of broilers against C. jejuni was investigated. During an in vivo trial, broiler chickens were prophylactically given feed with lyophilized hyperimmune or non-immunized egg yolk powder starting from day 1 after hatch. At day 11, broilers were inoculated with C. jejuni according to a seeder model. Five days later, all broilers were euthanized and cecal content was examined for C. jejuni colonization. No decrease in C. jejuni colonization was found. The freeze-drying resulted in a 16-fold decrease of the antibody titer in the yolk powder compared to the fresh yolks, presumably caused by structural changes in the antibodies. In conclusion, applying freeze-dried hyperimmune egg yolk failed to protect broilers against C. jejuni colonization, possibly because lyophilization affected the antibodies' functionality

Intestinal Microbial Ecology of Broilers Vaccinated and Challenged With Mixed Eimeria Species, and Supplemented with Essential Oil Blends

Intestinal microbiota is an important component in the development of defense mechanisms in the gut mucosa. This project determined the dynamics of intestinal microbial communities (MC) of broilers vaccinated at first day of age with live oocysts of Eimeria species and fed diets supplemented with 2 specific essential oil (EO) blends, Crina Poultry (CP) and Crina Alternate (CA). Five treatments were analyzed: 1) unmedicated-uninfected (UU) control; 2) unmedicated-infected (UI) control; 3) vaccinated with Advent cocci-vaccine and without feed additive (COV) supplements; 4) vaccinated with Advent and supplemented with CP; and 5) vaccinated with Advent and supplemented with CA. The EO blends were added at 100 ppm to the same basal diets. Chicks were gavage-infected at 19 d of age with Eimeria acervulina, Eimeria maxima, and Eimeria tenella. Duodenal, ileal, and cecal samples were taken from 12 birds per treatment just before the infection and 7 d after the challenge, pooled in 6 samples, and frozen. Denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of the bacterial 16S ribosomal DNA variable region. Results are presented as percentages of similarity coefficients (SC). Dendrograms of amplicon patterns indicated MC differences due to intestinal location, feed additives, and cocci infection. The EO blends CP and CA did affect MC in all gut sections. The cocci-infection caused drastic MC population shifts in duodenal, ileal, and cecal sections (36.7, 55.4, and 36.2% SC, respectively). The CP-supplemented birds had higher SC between pre- and postchallenge MC in duodenal and ileal (73.3, 81.8%) than COV (66.4, 66.5%). However, COV broilers had the smallest changes in cecal MC after infection (79.5% SC). We concluded that cocci-vaccination causes small changes in intestinal MC, but challenge causes drastic shifts. The EO blend supplementation modulates MC in cocci-vaccinated broilers, avoiding drastic shifts after a mixed coccidia infection. Correlations between MC dynamics and host responses are discussed