Ileal Bacterial Populations Research Articles

Depletion of gut microbiota suppresses spontaneous ileitis in mice driven by mitochondrial dysfunction induced by Phb1 deficiency

IntroductionDysbiosis in gut microbiota is associated with inflammatory bowel diseases (IBD), such as Crohn’s disease. Prohibitin 1 (PHB1) is a mitochondrial protein important in optimal mitochondrial respiration and is decreased in biopsies from IBD patients. Intestinal epithelial mitochondrial dysfunction is emerging as an underlying contributor to inflammation in IBD. Previous studies from our laboratory have demonstrated that mice with Phb1‐deficiency in the intestinal epithelium (Phb1iΔIEC) manifest mitochondrial dysfunction, Paneth cell defects, and spontaneous inflammation in the ileum with a penetrance of 87% at 12 weeks after inducing Phb1 deletion. This inflammation is associated with a reduction in the abundance of short chain acid (SCFA)‐producing bacteria, such as Blautia, Roseburia, Ruminococcus, and Coprococccus. However, little is known whether gut dysbiosis is a driver or consequence of ileitis during intestinal epithelial mitochondrial dysfunction. In the present study, we hypothesized that the gut microbiota is necessary to induce intestinal inflammation during epithelial cell mitochondrial dysfunction.MethodsPhb1iΔIEC mice and control Phb1fl/fllittermates were co‐housed and treated with broad spectrum antibiotics (ABX) (1 g/L ampicillin sodium salt, 1 g/L neomycin sulfate, 1 g/L metronidazole, and 500 mg/L vancomycin) in autoclaved drinking water for 4 weeks beginning 8 weeks after the induction of Phb1 deletion. Ileal stools were collected for 16S rRNA sequencing and quantification of SCFAs by liquid chromatography‐mass spectrometry. Ileum was collected for histological (inflammation) scoring after H&E staining and for immunofluorescent staining of lysozyme and Muc2 to quantitate Paneth cell defects (lysozyme allocation patterns, increase of lysozyme+/Muc2+ staining, and crypts devoid of lysozyme+ cells). Spleen weight was also measured at the time of sacrifice.ResultsIleal stool from Phb1iΔIEC mice exhibited a significant reduction in the SCFA butyrate compared to Phb1fl/fl littermates. 16S rRNA sequencing showed that ABX treatment abolished the ileal bacterial population in both Phb1fl/fland Phb1iΔIEC mice. ABX treatment ameliorated enlarged spleen weights, histological inflammation, and Paneth cell defects characteristic of Phb1iΔIEC mice to measurements noted in Phb1fl/fl mice.ConclusionsThese results suggest that mitochondrial dysfunction in IECs on its own is not sufficient to cause inflammation, but triggers disease when coupled with gut microbiota interaction. This is especially relevant to IBD given the prevalence of epithelial mitochondrial dysfunction in these patients.

Effect of olive leaf powder on the performance and ileal bacterial count of broilers.

This experiment was conducted to investigate the effects of olive leaf (OL) on the performance, abdominal fat pad and some ileal bacterial population of Cobb broiler chickens. A total number of 400 day-old chicks were randomly distributed into floor pens and reared under the same condition until 14 days of age. On day 14, each pen was randomly assigned to one of the five experimental treatments with four replicates of 20 male and female chicks. The dietary treatments were consisted of a control group which fed basal diet without OL entire period of the study and groups 2 to 5 that fed diets supplemented with 0.25, 0.50, 0.75 and 1.00% OL powder, respectively. On days 21 and 42 of the experiment, ileal digesta samples were collected under the sterile condition to evaluate ileal bacterial population. The results indicated that birds fed diets containing various levels of OL, had higher body weight gain (except for 1.00% OL) and lower feed conversion ratio compared to that of the control group. Dietary inclusion of OL resulted in a higher count of Lactobacillus sp. compared to the control group on 42 days of age, while Escherichia coli count significantly was not influenced. The abdominal fat pad was lower in birds fed OL supplemented diets. In conclusion, findings of the current experiment showed that the OL had positive effects on feed conversion ratio, abdominal fat pad deposition and ileal bacterial count of broiler chickens.

Improving growth performance and health status of meat-type quail by supplementing the diet with black cumin cold-pressed oil as a natural alternative for antibiotics.

Using antibiotics in poultry diets as growth promoters was reported to have harmful effects on consumers, so the current study was done to monitor the impact of dietary supplementation of antimicrobial black cumin oil (BCO) on carcass traits, growth performance, biochemical components, and ileal microbial populations of growing Japanese quails. Three hundred growing Japanese quails were used with three different treatments (0, 0.50, and 1.0g BCO/g diet). Birds fed diet supplemented with 0.5g BCO/kg diet showed significant increase in body weight comparing with the control and other treatment group. The daily feed intake and feed conversion ratio were significantly increased side by side with increasing BCO level in the diet. The majority of carcass characteristics were maximized by supplementing the quail diet with 0.5g BCO/kg. Moreover, liver functions, anti-oxidative capacity, lipid profile and anabolic hormones showed significant improvement in BCO-treated diets in a dose-dependent manner. The BCO showed highest antibacterial effect against Escherichia coli and Salmonella enterica. The ileal bacterial populations, i.e., total bacterial count (TBC), coliform, Salmonella species, and Escherichia coli were decreased in birds supplemented with BCO 0.5 and 1.0 BCO g/kg compared with the control diet. Based on the aforementioned results, conclusion could be drawn that supplementing quail with BCO in their diet could improve productive performance traits and enhance health aspect of the birds.

Effects of dietary inclusion of silymarin on performance, intestinal morphology and ileal bacterial count in aflatoxin-challenged broiler chicks.

This study was conducted to investigate the effect of dietary supplementation of silymarin on performance, jejunal morphology and ileal bacterial population in broiler chicks intoxicated with a mix of aflatoxins. A total of three hundred thirty six 7-day-old Ross broiler chicks were randomly distributed between seven experimental groups with four replicates of 12 birds each. Experimental treatments consisted of a control group (unchallenged), and a 2×3 factorial arrangement, including two aflatoxin levels (0.5 and 2ppm) and three levels of silymarin (0, 500 and 1000ppm). Birds were challenged with a mix of aflatoxins from 7 to 28days of age. Results showed that increasing aflatoxin level resulted in decreased average daily feed intake (ADFI) and weight gain (ADWG), consequently impaired feed conversion ratio (FCR) throughout the trial period. Dietary supplementation of silymarin resulted in the marked increases in ADFI and ADWG, and improved FCR values in aflatoxin-challenged chicks. Ileal bacterial populations at days 28 and 42 of age were increased by incremental levels of aflatoxins. On the other hand, dietary silymarin supplementation suppressed ileal populations of Escherichia coli, Salmonella, Klebsiella and total negative bacteria in aflatoxicated birds. Increase in dietary aflatoxin level resulted in the decreased villi height, villi height-to-crypt depth ratio (VH:CD), villi surface area and apparent villi absorptive area, while it increased crypt depth, goblet cell count and lymphoid follicular diameter. Feeding silymarin at the level of 1000ppm increased villi height and VH:CD in aflatoxicated birds. Present results indicate that dietary inclusion of silymarin could improve performance by suppressing ileal bacteria and enhancing absorptive surface area in aflatoxin-challenged broiler chicks.

Effects of enzymatic treatment and shell content of palm kernel expeller meal on performance, nutrient digestibility, and ileal bacterial population in broiler chickens

The objective of this study was to examine the effects of enzymatic treatment and shell content of palm kernel expeller meal (PKE) on the performance, nutrient digestibility, and ileal bacteria population in broiler chickens. Part of the PKE sample was sieved (3 mm) to remove the shell (lower shell PKE) and part was used as is. The primary mannan-oligosaccharides in the experimental diets were determined using HPLC analysis. During the finisher phase, one hundred male broiler chickens (Cobb-500) were fed a control diet or the diets containing 200 g/kg of normal PKE (70 g/kg shell), low shell PKE (30 g/kg shell), enzymatically (cellulase and mannanase) treated PKE, or low shell, enzymatically treated PKE. The DM, CP, and ether extract digestibility coefficients were measured using acid insoluble ash as an insoluble marker. The quantitative rea-time PCR was used to determine the ileal bacteria populations. The enzymatic treatment significantly increased the mannose and also mannan-oligosaccharides content of PKE. Feed intake was not affected by dietary inclusion of PKE. In the birds fed the low shell PKE diet the average daily weight gain was lower and the feed conversion ratio was higher than those in the control and other PKE fed groups. The digestibility coefficients of dry matter and ash were lower in PKE containing diets than the control diet. However, there were no differences in the crude protein and ether extracts digestibility coefficients between the diets containing the enzymatic treated PKE (normal or low shell) and the control diet. The lowest ileal Lactobacilli population was found in the chickens fed the low shell PKE diet. Dietary normal PKE or low shell-enzymatic treated PKE decreased the Escherichia coli population compared to the control diet. The results suggested that PKE could be included up to 200 g/kg in the finisher diet without any apparent adverse effect on performance in broilers; however, any screening practice to reduce the shell content of PKE without enzymatic degradation of β-mannan, decreased its nutritive value.

Effect of dietary supplementation of mannanoligosaccharides on growth performance, ileal microbial counts, and jejunal morphology in broiler chicks exposed to aflatoxins

The present study was conducted to evaluate the effects of dietary inclusion of mannanoligosaccharides (MOS) on growth performance, ileal microbial population, and jejunal morphology in aflatoxin-challenged broiler chicks. A total of 336 seven-day-old Ross broiler chicks were randomly assigned into 7 experimental treatments with 4 replicates of 12 chicks each. Experimental treatments consisted of a control group (unchallenged group), and a 2×3 factorial arrangement of treatments, including 2 aflatoxin levels (0.5 and 2ppm) and 3 supplemental MOS levels (0, 1, and 2g/kg). Broiler chicks were challenged with a mix of aflatoxins during 7–28 d of age. Results showed that increasing aflatoxin level resulted in a marked decrease (P<0.01) in average daily feed intake (ADFI) and subsequent average daily gain (ADG); consequently it impaired (P<0.001) feed conversion ratio (FCR). Dietary MOS supplementation increased ADFI (P<0.01) and ADG (P<0.001) in aflatoxin-challenged chicks, resulted in the improvements in FCR values. The retarded ADG was ameliorated by inclusion of 2g/kg of MOS into the diet of aflatoxin-challenged broiler chicks. Although incremental levels of aflatoxin decreased (P<0.05) carcass yield, dietary supplementation of MOS up to 2g/kg resulted in an increase in carcass yield. Contamination with 2ppm aflatoxin resulted in increases (P<0.001) in ileal enumerations of Escherichia coli, Salmonella, Klebsiella, and total negative bacteria at both 28 and 42 d of age. Although the lowest bacterial count was assigned to the control (unchallenged) group, supplemental MOS decreased ileal bacterial populations in aflatoxin-challenged broiler chicks. Dietary supplementation of 2g/kg of MOS was more effective (P<0.05) in depression of ileal microbial counts in broiler chicks challenged with 0.5ppm aflatoxin. Incremental levels of aflatoxin resulted in considerable (P<0.001) decreases in villi height, villi height to crypt depth ratio, villi absorptive area, and apparent villi absorptive area. Moreover, dietary aflatoxin contamination increased crypt depth, goblet cell counts, and lymphoid follicular diameter. These changes, however, were partly modulated by dietary MOS supplementation up to 2g/kg. The present results indicated that although aflatoxicosis reduced growth performance, dietary inclusion of MOS ameliorated the retarded growth via suppressing ileal pathogenic bacteria and enhancing absorptive surface area in broiler chicks.

Temporal Relationships Exist Between Cecum, Ileum, and Litter Bacterial Microbiomes in a Commercial Turkey Flock, and Subtherapeutic Penicillin Treatment Impacts Ileum Bacterial Community Establishment

Gut health is paramount for commercial poultry production, and improved methods to assess gut health are critically needed to better understand how the avian gastrointestinal tract matures over time. One important aspect of gut health is the totality of bacterial populations inhabiting different sites of the avian gastrointestinal tract, and associations of these populations with the poultry farm environment, since these bacteria are thought to drive metabolism and prime the developing host immune system. In this study, a single flock of commercial turkeys was followed over the course of 12 weeks to examine bacterial microbiome inhabiting the ceca, ileum, and corresponding poultry litter. Furthermore, the effects of low-dose, growth-promoting penicillin treatment (50 g/ton) in feed on the ileum bacterial microbiome were also examined during the early brood period. The cecum and ileum bacterial communities of turkeys were distinct, yet shifted in parallel to one another over time during bird maturation. Corresponding poultry litter was also distinct yet more closely represented the ileal bacterial populations than cecal bacterial populations, and also changed parallel to ileum bacterial populations over time. Penicillin applied at low dose in feed significantly enhanced early weight gain in commercial poults, and this correlated with predictable shifts in the ileum bacterial populations in control versus treatment groups. Overall, this study identified the dynamics of the turkey gastrointestinal microbiome during development, correlations between bacterial populations in the gastrointestinal tract and the litter environment, and the impact of low-dose penicillin on modulation of bacterial communities in the ileum. Such modulations provide a target for alternatives to low-dose antibiotics.

Specific comensal bacteria modulate epithelial glycosylaion (59.5)

Abstract Commensal bacteria constantly reside in our mucosal sites, especially in the intestine and create a mutually beneficial condition of symbiosis with the host. The physical and molecular crosstalk between host and gut microbiota is established at the surface of intestinal epithelial layer. It has been reported that specific epithelial carbohydrate chains, fucoses, are involved in the attachment of bacteria and viruses and ablation of these fucoses seems to be associated with the onset of Crohn’s disease. In spite of this important role, the mechanism of the induction and regulation of epithelial fucoses is not fully understood. Here, we show that specific commensal bacteria, segmented filamentous bacteria (SFB), physiologically induce fucoses on the ileal epithelial cells. To analyze the role of commensal bacteria in the induction of fucosylated epithelial cells (F-ECs), we firstly checked germfree mice. F-ECs were not found in germfree mice, while a large number of F-ECs were observed in the ileum of SPF mice. When we analyzed the ileal bacterial population to identify bacteria responsible for the induction of F-ECs, SFB were dominant in the ileum. Mono-colonization of SFB led to the development of F-ECs in germfree mice. Furthermore, F-ECs were abolished in SFB deficient mice bred in Jackson laboratory, indicating that SFB physiologically induce F-ECs. Our findings provide the basis of mutually beneficial system between the host and commensal bacteria.

Ileal microbiota of growing pigs fed different dietary calcium phosphate levels and phytase content and subjected to ileal pectin infusion1

Two experiments with growing pigs were conducted to determine the effects of dietary P and Ca levels, phytase supplementation, and ileal pectin infusion on changes in bacterial populations in the ileum and on ileal and fecal fermentation patterns. Growing pigs (BW 30.1 +/- 1.3 kg) were fitted with simple T-cannulas at the distal ileum and were fed a low-P corn-soybean meal control diet (3 g of P/kg), or the control diet supplemented with either 15 g of monocalcium phosphate (MCP)/kg (Exp. 1) or 1,000 phytase units of phytase/kg (Exp. 2). Daily infusion treatments consisted of either 60 g of pectin dissolved in 1.8 L of demineralized water or 1.8 L of demineralized water as a control infusion, infused via the ileal cannula. In each experiment, 8 barrows were assigned to 4 dietary treatments according to a double incomplete 4 x 2 Latin square design. The dietary treatments in Exp. 1 were the control diet with water infusion, the control diet with pectin infusion, the MCP diet with water infusion, or the MCP diet with pectin infusion. In Exp. 2, the pigs received the same control treatments as in Exp. 1 and the phytase diet in combination with water or pectin infusion. Gene copy numbers of total bacteria, Lactobacillus spp., Lactobacillus reuteri, Lactobacillus amylovorus/Lactobacillus sobrius, Lactobacillus mucosae, Enterococcus spp., Enterococcus faecium, Enterococcus faecalis, bifidobacteria, the Clostridium coccoides cluster, the Clostridium leptum cluster, the Bacteroides-Prevotella-Porphyrmonas group, and Enterobacteriaceae were determined by quantitative PCR in DNA extracts of ileal digesta. In Exp. 1, addition of MCP reduced ileal gene copy numbers of Enterococcus spp. (P = 0.048), E. faecium (P = 0.015), and the C. leptum cluster (P = 0.028), whereas pectin infusion enhanced (P = 0.008) ileal d-lactate concentration. In Exp. 2, supplemental phytase led to greater ileal gene copy numbers of the C. coccoides (P = 0.041) and C. leptum (P = 0.048) clusters and the Bacteroides-Prevotella-Porphyrmonas group (P = 0.033), whereas it reduced (P = 0.027) fecal n-butyrate concentration. Pectin infusion reduced (P = 0.005) ileal gene copy number of the C. leptum cluster. In conclusion, ileal bacterial populations and fermentation patterns are susceptible to changes in the intestinal availability of Ca and P as well as to the supply of pectin as a fermentable substrate. Greater intestinal Ca availability decreased the numbers of some gram-positive bacteria, whereas greater P availability in the small intestine caused by phytase activity enhanced the growth of strictly anaerobic bacteria.

Change in the Ileal Bacterial Population of Turkeys Fed Different Diets and After Infection with Salmonella as Determined with Denaturing Gradient Gel Electrophoresis of Amplified 16S Ribosomal DNA

Changes in ileal bacterial populations of Salmonella-infected turkeys fed different diets were analyzed by using 16S-V3 PCR denaturing gradient gel electrophoresis. Turkeys raised on litter flooring were fed wheat- and corn-based diets with and without enzyme preparations (XY1 and XY2, respectively) from 0 to 126 d. Preparation XY1 contained exclusively endoxylanase, whereas preparation XY2 contained endoxylanase, protease, and α-amylase (Danisco, Wiltshire, UK). The dietary activity levels of XY1 and XY2 were 2,500 and 650 endo-1,4-β-xylanase units/kg of feed, respectively. Microbial DNA was extracted from the ileal content of 16-wk-old turkeys, and the 16S rDNA gene was amplified by PCR and analyzed by denaturing gradient gel electrophoresis. Diversity indexes, including richness (number of species, S), evenness (relative distribution of species, EH), diversity (using Shannon's index, H′), and Sorenson's pairwise similarities coefficient (measures the species in common between different habitats, Cs) were calculated. Additionally, diversity indexes were associated with Salmonella prevalence determined from fresh fecal droppings collected from each pen. On the basis of contrast analysis, the wheat-based diets resulted in higher microbial diversity indexes than the corn-based diets (S = 10 vs. 12; EH = 0.9 vs. 0.8; H′ = 2.2 vs. 1.9, P < 0.05). Likewise, enzyme supplementation stimulated growth of the microbiota and increased the diversity indexes in comparison with unsupplemented treatments (S = 13 vs. 10; EH = 0.9 vs. 0.8; H′ = 2.2 vs. 1.9, P < 0.05). Salmonella prevalence was higher (P < 0.05) at 15 wk in turkeys fed the corn-based diet (Salmonella prevalence = 50%) than in turkeys fed the corn-enzyme (Salmonella prevalence = 13%) and wheat-based (Salmonella prevalence = 0%) dietary treatments. Therefore, contrast analysis showed that birds fed the corn control diet had lower microbiota diversity but higher Salmonella prevalence than birds fed the enzyme-supplemented and wheat-based diets. In contrast, birds fed the wheat-based diets had higher diversity but lower Salmonella prevalence than birds fed the corn-based diets. High dietary nonstarch polysaccharides from wheat and dietary exogenous enzyme supplementation promoted microbial community diversity and apparently discouraged Salmonella colonization through competitive exclusion. Nonstarch polysaccharides and dietary exogenous enzyme supplementation may be practical tools to control enteric pathogens and benefit the intestinal health and food safety of the birds.

The Effect of Gender on the Bacterial Community in the Gastrointestinal Tract of Broilers

The effect of gender on the growth, carcass yield, and nutritional requirements of chickens has been well documented, but little is known about how the sex of a chicken affects the bacterial population of the gastrointestinal tract. Therefore, our objective was to evaluate the biodiversity of the bacterial community in the gastrointestinal tract of male and female broilers. An experiment was conducted with Cobb 500 broiler chicks that were vent sexed at 0 d of age and allocated to 8 pens of 25 chicks per gender. All birds were fed a nonmedicated corn-soybean meal starter diet from 0 to 21 d of age. At 3, 7, 14, and 21 d of age, chicks were randomly selected and ileums were taken for bacterial sampling. Bacterial DNA was isolated from the digesta of the ileum, and denaturing gradient gel electrophoresis was used to examine PCR-amplified fragments of 16S ribosomal DNA. Denaturing gradient gel electrophoresis analyses revealed that the bacterial communities separated into 2 gender-specific groups, with less than 30% similarity between populations. Furthermore, as the birds aged, the similarity of the intestinal bacterial community decreased within each gender. Although ileal bacterial population differences within and between genders were noted as early as d 3, differences in growth rate between males and females were not noted until d 21 (data not shown). This suggested that non-growth-related factors influenced the composition of intestinal bacterial communities.