Intestinal Fermentation Research Articles

A Review of Potentials of Black Pepper (<em>Piper Nigrum</em> L.) to Replace Antibiotics in Monogastric Animal Nutrition

This review was conducted to ascertain the potentials of black pepper as performance enhancement feed additives in the diets of monogastric animals in place of pharmaceutical antibiotics. Black pepper is a spice grown in the tropical areas of the world with pungent characteristics and it is noted for tasting hot. A climbing plant which can grow to a height of 1,500 metres, traded worldwide, it is of significance in human nutrition and medicine. Black pepper seeds are tiny but bigger than alligator pepper. It is made up of essential oils, acids, esters, alcohol and phenols. The essential oils which gives it its characteristic flavor is basically composed of group of organic compounds called terpenes. Terpenes give black pepper its antibacterial property. The essential oils could perforate the bacteria cell to exert its antibacterial property. Other potentials of black pepper include its ability to increase saliva secretion, hydrochloric acid, gastric juice, bile, pancreatic juice and mucus and hence immune stability. Negative effect of rancidity both in the feed and the body could be reduced by black pepper by counteracting free radicals (e.g. OH-). Black pepper improves nutrients digestibility, absorption and reduces intestinal fermentation. On the other hand black pepper is susceptible to mold attack and therefore should be well stored.

Consumption of Breads Containing In Situ–Produced Arabinoxylan Oligosaccharides Alters Gastrointestinal Effects in Healthy Volunteers 3

Arabinoxylan oligosaccharides (AXOS) are studied as food compounds with prebiotic potential. Here, the impact of consumption of breads with in situ-produced AXOS on intestinal fermentation and overall gastrointestinal characteristics was evaluated in a completely randomized, double-blind, controlled, cross-over study. Twenty-seven healthy volunteers consumed 180 g of wheat/rye bread with or without in situ-produced AXOS (WR+ and WR-, respectively) daily for 3 wk. Consumption of WR+ corresponded to an AXOS intake of ~2.14 g/d. Refined wheat flour bread without AXOS (W-) (180 g/d) was provided during the 3-wk run-in and wash-out periods. At the end of each treatment period, participants collected urine for 48 h as well as a feces sample. Additionally, all participants completed a questionnaire about stool characteristics and gastrointestinal symptoms during the last week of each period. Urinary phenol and p-cresol excretions were significantly lower after WR+ intake compared to WR-. Consumption of WR+ significantly increased fecal total SCFA concentrations compared to intake of W-. The effect of WR+ intake was most pronounced on butyrate, with levels 70% higher than after consumption of W- in the run-in or wash-out period. Consumption of WR+ tended to selectively increase the fecal levels of bifidobacteria (p = 0.06) relative to consumption of W-. Stool frequency increased significantly after intake of WR+ compared to WR-. In conclusion, consumption of breads with in situ-produced AXOS may favorably modulate intestinal fermentation and overall gastrointestinal properties in healthy humans.

Functional dysbiosis within the gut microbiota of patients with constipated‐irritable bowel syndrome

The role of the gut microbiota in patho-physiology of irritable bowel syndrome (IBS) is suggested by several studies. However, standard cultural and molecular methods used to date have not revealed specific and consistent IBS-related groups of microbes. To explore the constipated-IBS (C-IBS) gut microbiota using a function-based approach. The faecal microbiota from 14 C-IBS women and 12 sex-match healthy subjects were examined through a combined strictly anaerobic cultural evaluation of functional groups of microbes and fluorescent in situ hybridisation (16S rDNA gene targeting probes) to quantify main groups of bacteria. Starch fermentation by C-IBS and healthy faecal samples was evaluated in vitro. In C-IBS, the numbers of lactate-producing and lactate-utilising bacteria and the number of H(2) -consuming populations, methanogens and reductive acetogens, were at least 10-fold lower (P < 0.05) compared with control subjects. Concomitantly, the number of lactate- and H(2) -utilising sulphate-reducing population was 10 to 100 fold increased in C-IBS compared with healthy subjects. The butyrate-producing Roseburia - E. rectale group was in lower number (0.01 < P < 0.05) in C-IBS than in control. C-IBS faecal microbiota produced more sulphides and H(2) and less butyrate from starch fermentation than healthy ones. A major functional dysbiosis was observed in constipated-irritable bowel syndrome gut microbiota, reflecting altered intestinal fermentation. Sulphate-reducing population increased in the gut of C-IBS and were accompanied by alterations in other microbial groups. This could be responsible for changes in the metabolic output and enhancement in toxic sulphide production which could in turn influence gut physiology and contribute to IBS pathogenesis.

Fermentation of animal components in strict carnivores: A comparative study with cheetah fecal inoculum1,2

The natural diet of felids contains highly digestible animal tissues but also fractions resistant to small intestinal digestion, which enter the large intestine where they may be fermented by the resident microbial population. Little information exists on the microbial degradability of animal tissues in the large intestine of felids consuming a natural diet. This study aimed to rank animal substrates in their microbial degradability by means of an in vitro study using captive cheetahs fed a strict carnivorous diet as fecal donors. Fresh cheetah fecal samples were collected, pooled, and incubated with various raw animal substrates (chicken cartilage, collagen, glucosamine-chondroitin, glucosamine, rabbit bone, rabbit hair, and rabbit skin; 4 replicates per substrate) for cumulative gas production measurement in a batch culture technique. Negative (cellulose) and positive (casein and fructo-oligosaccharides; FOS) controls were incorporated in the study. Additionally, after 72 h of incubation, short-chain fatty acids (SCFA), including branched-chain fatty acids (BCFA), and ammonia concentrations were determined for each substrate. Glucosamine and glucosamine-chondroitin yielded the greatest organic matter cumulative gas volume (OMCV) among animal substrates (P < 0.05), whereas total SCFA production was greatest for collagen (P < 0.05). Collagen induced an acetate production comparable with FOS and a markedly high acetate-to-propionate ratio (8.41:1) compared with all other substrates (1.67:1 to 2.97:1). Chicken cartilage was rapidly fermentable, indicated by a greater maximal rate of gas production (R(max)) compared with all other substrates (P < 0.05). In general, animal substrates showed an earlier occurrence for maximal gas production rate compared with FOS. Rabbit hair, skin, and bone were poorly fermentable substrates, indicated by the least amount of OMCV and total SCFA among animal substrates (P < 0.05). The greatest amount of ammonia production among animal substrates was measured after incubation of collagen and rabbit bone (P < 0.05). This study provides the first insight into the potential of animal tissues to influence large intestinal fermentation in a strict carnivore, and indicates that animal tissues have potentially similar functions as soluble or insoluble plant fibers in vitro. Further research is warranted to assess the impact of fermentation of each type of animal tissue on gastro-intestinal function and health in the cheetah and other felid species.

Evaluation of the effects of dietary organic germanium, ge-132, and raffinose supplementation on caecal flora in rats.

Poly-trans-[(2-carboxyethyl) germasesquioxane] (Ge-132) is the most common organic germanium compound. The ingestion of Ge-132 promotes bile secretion. We assessed the rat caecal characteristics after the administration of Ge-132 and raffinose, a prebiotic oligosaccharide, because both Ge-132 and some prebiotics can change the fecal color to yellow. We also compared the changes in the caecal flora caused by the two compounds. In addition, we evaluated the simultaneous administration of Ge-132 and raffinose and their effects on β-glucuronidase activity, which is known to be a factor related to colon cancer. Male Wistar rats (three weeks old) were given one of the following diets: 1) a control diet (control group), 2) a diet containing 0.05% Ge-132 (Ge-132 group), 3) a diet containing 5% raffinose (RAF group) or 4) a diet containing 0.05% Ge-132 + 5% raffinose (GeRAF group). The Bifidobacterium, Lactobacillus and total bacteria counts were significantly increased by the dietary raffinose, and Ge-132 did not suppress this increase. The raffinose intake increased caecal acetic acid production significantly. The activity of β-glucuronidase in the caecal contents was increased by dietary Ge-132, whereas dietary raffinose decreased the β-glucuronidase activity significantly. These results indicate that the simultaneous intake of dietary raffinose and Ge-132 does not inhibit the effects of either compound on intestinal fermentation and bile secretion. Additionally, the simultaneous intake of both raffinose and Ge-132 could abrogate the increase in β-glucuronidase activity induced by Ge-132 alone.

Pharmacokinetic comparison of ginsenoside metabolite IH-901 from fermented and non-fermented ginseng in healthy Korean volunteers

Ethnopharmacological relevanceIH-901 (20-O-beta-d-glucopyranosyl-20(S)-protopanaxadiol) is a novel ginseng saponin metabolite formed by human intestinal bacteria and is known to have antitumor and antimetastatic effects. However, there has been no pharmacokinetic study of IH-901 in human beings. Aim of the studyThe aim of this study was to investigate the pharmacokinetic differences of IH-901 from fermented and non-fermented ginseng. Materials and methodsTo investigate whether the pharmacokinetics of IH-901 differ between fermented and non-fermented ginseng, an open label, randomized, single dose, fasting, two-period, cross-over, pharmacokinetic study was conducted. A total of 24 healthy Korean male volunteers participated in this study. All subjects were allocated into two equal groups and administered 3g of fermented or non-fermented Panax ginseng. Serial blood samples for pharmacokinetic analysis were collected in the 24h after dosing. Plasma IH-901 concentration was measured by a validated high-performance liquid chromatography–tandem mass spectrometry (LC–MS/MS) method. Pharmacokinetic parameters including AUCt, Cmax, and Tmax were calculated by noncompartmental models in the BA-CALC program (KFDA, 2008, 1.0.0, Korea). ResultsAfter oral administration of fermented ginseng, 5 subjects experienced diarrhea. The means of AUCt and Cmax were significantly different between the two groups. In the fermented ginseng group, AUCt was 2083.09±91.97ngh/mL, a 15.5-fold increase over that of IH-901 from the non-fermented group (134.50±63.10ngh/mL), and the mean Cmax was 325.00±91.97ng/mL in the fermented ginseng group, a 27-fold higher value than that in the non-fermented group (13.88±7.24ng/mL). Tmax was 3.29±1.00 and 12.04±4.96h in the fermented and non-fermented group, respectively. ConclusionsThe results of this study showed that the pharmacokinetic parameters of IH-901 from fermented Panax ginseng are different from those of non-fermented ginseng, from which IH-901 is formed by intestinal fermentation.

Prebiotic effects and intestinal fermentation of cereal arabinoxylans and arabinoxylan oligosaccharides in rats depend strongly on their structural properties and joint presence

Cereal arabinoxylan (AX) is one of the main dietary fibers in a balanced human diet. To gain insight into the importance of structural features of AX for their prebiotic potential and intestinal fermentation properties, a rat trial was performed. A water unextractable AX-rich preparation (WU-AX, 40% purity), water extractable AX (WE-AX, 81% purity), AX oligosaccharides (AXOS, 79% purity) and combinations thereof were included in a standardized diet at a 5% AX level. WU-AX was only partially fermented in the ceco-colon and increased the level of butyrate and of butyrate producing Roseburia/E. rectale spp. Extensive fermentation of WE-AX and/or AXOS reduced the pH, suppressed relevant markers of the proteolytic breakdown and induced a selective bifidogenic response. Compared with WE-AX, AXOS showed a slightly less pronounced effect in the colon as its fermentation was virtually complete in the cecum. Combining WU-AX and AXOS caused a striking synergistic increase in cecal butyrate levels. WU-AX, WE-AX and AXOS together combined a selective bifidogenic effect in the colon with elevated butyrate levels, a reduced pH and suppressed proteolytic metabolites. The prebiotic potential and fermentation characteristics of cereal AX depend strongly on their structural properties and joint presence.

Evaluation of gastrointestinal transit in rats fed dietary fibres differing in their susceptibility to large intestine fermentation

The rate and extent of in situ digesta transit after ingestion of diets containing dietary fibres differing in their susceptibility to large intestine fermentation were investigated. One hundred and twenty rats were fed diets containing 7.5% cellulose, inulin, potato fibre or maize starch for 3days, then the same diets with titanium dioxide (TiO2) for 3days, followed by diets without TiO2 for 2days. In all diets, TiO2 ratios rapidly increased within 24h and reached a maximum level in duodenum, caecum and colon within 2–3days. Inulin, potato fibre and maize starch-fed rats showed higher levels of caecal short-chain fatty acids, lower faecal polysaccharide concentrations, and reduced faecal output than the rats fed cellulose. Inulin was highly susceptible to caecal microbial fermentation compared to the other dietary fibres. Transit of these dietary fibres through the GI tract was rapid, and the rate of digesta transit was not affected by dietary fibre fermentability in the large intestine.

Chemical Composition of Natural and Polyphenol-free Apple Pomace and the Effect of This Dietary Ingredient on Intestinal Fermentation and Serum Lipid Parameters in Rats

Unprocessed pomace containing 61% of dietary fiber (DF) and 0.23% of polyphenols (PP) and ethanol- or ethanol/acetone-extracted pomaces containing 66% DF and 0.10% PP and 67% DF and 0.01% PP, respectively, were subjected to a 4 week study in rats. The aim of the study was assessing the advantages of dietary supplementation with the above pomaces. To measure the animal response to dietary treatments, parameters describing cecal fermentation and lipoprotein profile were assessed. The dietary use of 5% unprocessed pomace caused an increase in cecal short-chain fatty acid (SCFA) production and a decrease in blood triacylglycerols, leading to a drop in serum atherogenic index. Ethanol-extracted pomace increased the glycolytic activity of cecal microbiota and decreased cecal branched-chain fatty acid production, whereas acetone extraction led to lower cecal ammonia concentration, decreased colonic pH value, and higher HDL/total cholesterol ratio. The variations in the atherogenic index indicate flavonoids as the key pomace component in relation to blood lipid profile benefits.

Perceived food hypersensitivity: A review of 10 years of interdisciplinary research at a reference center

Perceived food hypersensitivity is a prevalent, but poorly understood condition. In this review article, we summarize narratively recent literature including results of our 10 years' interdisciplinary research program dealing with such patients. The patients (more than 400) included in our studies were all adults referred to a university hospital because of gastrointestinal complaints self-attributed to food hypersensitivity. Despite extensive examinations, food allergy was seldom diagnosed. The majority of the patients fulfilled the diagnostic criteria for irritable bowel syndrome. In addition, most suffered from several extra-intestinal health complaints and had considerably impaired quality of life. However, psychological factors could explain only approximately 10% of the variance in the patients' symptom severity and 90% of the variance thus remained unexplained. Intolerance to low-digestible carbohydrates was a common problem and abdominal symptoms were replicated by carbohydrate ingestion. A considerable number of patients showed evidence of immune activation by analyses of B-cell activating factor, dendritic cells and “IgE-armed” mast cells. Multiple factors such as immune activation, disturbed intestinal fermentation, enteric dysmotility, post-infectious changes and “local” allergy in the gut as well as psychological disturbances may play a role in the pathophysiology of perceived food hypersensitivity. Hence, our results support the view that management of these patients should be interdisciplinary.

A metabolic link between mitochondrial ATP synthesis and liver glycogen metabolism: NMR study in rats re-fed with butyrate and/or glucose

BackgroundButyrate, end-product of intestinal fermentation, is known to impair oxidative phosphorylation in rat liver and could disturb glycogen synthesis depending on the ATP supplied by mitochondrial oxidative phosphorylation and cytosolic glycolysis.MethodsIn 48 hr-fasting rats, hepatic changes of glycogen and total ATP contents and unidirectional flux of mitochondrial ATP synthesis were evaluated by ex vivo 31P NMR immediately after perfusion and isolation of liver, from 0 to 10 hours after force-feeding with (butyrate 1.90 mg + glucose 14.0 mg.g-1 body weight) or isocaloric glucose (18.2 mg.g-1 bw); measurements reflected in vivo situation at each time of liver excision. The contribution of energetic metabolism to glycogen metabolism was estimated.ResultsA net linear flux of glycogen synthesis (~11.10 ± 0.60 μmol glucosyl units.h-1.g-1 liver wet weight) occurred until the 6th hr post-feeding in both groups, whereas butyrate delayed it until the 8th hr. A linear correlation between total ATP and glycogen contents was obtained (r2 = 0.99) only during net glycogen synthesis. Mitochondrial ATP turnover, calculated after specific inhibition of glycolysis, was stable (~0.70 ± 0.25 μmol.min-1.g-1 liver ww) during the first two hr whatever the force-feeding, and increased transiently about two-fold at the 3rd hr in glucose. Butyrate delayed the transient increase (1.80 ± 0.33 μmol.min-1.g-1 liver ww) to the 6th hr post-feeding. Net glycogenolysis always appeared after the 8th hr, whereas flux of mitochondrial ATP synthesis returned to near basal level (0.91 ± 0.19 μmol.min-1.g-1 liver ww).ConclusionIn liver from 48 hr-starved rats, the energy need for net glycogen synthesis from exogenous glucose corresponds to ~50% of basal mitochondrial ATP turnover. The evidence of a late and transient increase in mitochondrial ATP turnover reflects an energetic need, probably linked to a glycogen cycling. Butyrate, known to reduce oxidative phosphorylation yield and to induce a glucose-sparing effect, delayed the transient increase in mitochondrial ATP turnover and hence energy contribution to glycogen metabolism.

Intestinal Fermentation Assessed by Intraluminal pH in Subjects With Abdominal Bloating

Abdominal bloating symptoms are highly prevalent in subjects with functional GI disorders and are associated with increased healthcare utilization and reduced quality of life [APT 2010]. Altered intestinal transit and abnormal intraluminal fermentation have been proposed as possible pathophysiological mechanisms for these symptoms. We have previously demonstrated slower colonic transit in subjects with abdominal bloating compared to subjects without bloating. In this study we investigated the hypothesis that abdominal bloating symptoms are associated with abnormally increased intestinal fermentation.Aim: To investigate and compare the magnitude and site of intestinal fermentation in subjects with functional GI symptoms and bloating (FGI-B) and healthy controls (HC) by measuring pH in the GI lumen. Methods: We studied a total of 47 subjects; FGI-B (n=37) and HC (n=10). Intestinal intraluminal pH was used as a surrogate marker for intestinal fermentation. The intestinal pH levels were measured at different segments of the GI tract using a wireless motility capsule (WMC). Comparisons of transit time and pH variables between the groups were done using t-test; correlation analyses were done using Spearman Correlation Coefficients. Results: Intestinal pH levels were significantly lower at the proximal colon (Q1) of subjects with FGI-B compared to HC (mean pH 6.27 vs. 6.84; p=0.008) suggesting a significantly higher intraluminal intestinal fermentation at this segment of the GI tract in these subjects. The mean intraluminal colonic pH levels in the FGI-B group were also lower than that of HC at other segments of the large intestine; however, statistical differences were noticed only in the proximal and total colon. Mean colonic pH levels at the four (proximal to distal) colonic segments and the total colon are provided in the following Table. There were no noticeable differences between the groups in mean pH levels at any of the segments of the small bowel. The average total colonic pH significantly correlated with the total colonic transit time (r=0.34; p=0.014). However, no correlation was found between the average small bowel pH and small bowel transit time.Conclusions: We provide evidence of abnormal intestinal fermentation in subjects with functional GI symptoms and bloating. We demonstrate that bloating symptoms are associated with increased fermentation in the large rather than the small bowel. WMCmay be helpful in identifying underlying physiological abnormalities and guide treatment in patients with bloating symptoms. Mean intraluminal pH levels in subjects with abdominal bloating and healthy controls

Characterization of the Inflammatory Response in Idiopathic Gastroparesis Reveals a Role for Macrophage Derived Factors

Abdominal bloating symptoms are highly prevalent in subjects with functional GI disorders and are associated with increased healthcare utilization and reduced quality of life [APT 2010]. Altered intestinal transit and abnormal intraluminal fermentation have been proposed as possible pathophysiological mechanisms for these symptoms. We have previously demonstrated slower colonic transit in subjects with abdominal bloating compared to subjects without bloating. In this study we investigated the hypothesis that abdominal bloating symptoms are associated with abnormally increased intestinal fermentation.Aim: To investigate and compare the magnitude and site of intestinal fermentation in subjects with functional GI symptoms and bloating (FGI-B) and healthy controls (HC) by measuring pH in the GI lumen. Methods: We studied a total of 47 subjects; FGI-B (n=37) and HC (n=10). Intestinal intraluminal pH was used as a surrogate marker for intestinal fermentation. The intestinal pH levels were measured at different segments of the GI tract using a wireless motility capsule (WMC). Comparisons of transit time and pH variables between the groups were done using t-test; correlation analyses were done using Spearman Correlation Coefficients. Results: Intestinal pH levels were significantly lower at the proximal colon (Q1) of subjects with FGI-B compared to HC (mean pH 6.27 vs. 6.84; p=0.008) suggesting a significantly higher intraluminal intestinal fermentation at this segment of the GI tract in these subjects. The mean intraluminal colonic pH levels in the FGI-B group were also lower than that of HC at other segments of the large intestine; however, statistical differences were noticed only in the proximal and total colon. Mean colonic pH levels at the four (proximal to distal) colonic segments and the total colon are provided in the following Table. There were no noticeable differences between the groups in mean pH levels at any of the segments of the small bowel. The average total colonic pH significantly correlated with the total colonic transit time (r=0.34; p=0.014). However, no correlation was found between the average small bowel pH and small bowel transit time.Conclusions: We provide evidence of abnormal intestinal fermentation in subjects with functional GI symptoms and bloating. We demonstrate that bloating symptoms are associated with increased fermentation in the large rather than the small bowel. WMCmay be helpful in identifying underlying physiological abnormalities and guide treatment in patients with bloating symptoms. Mean intraluminal pH levels in subjects with abdominal bloating and healthy controls

Development of a headspace solid-phase microextraction gas chromatography–mass spectrometric method for the determination of short-chain fatty acids from intestinal fermentation

The determination of short-chain fatty acids produced by colonic fermentation can provide useful information as a tool to evaluate prebiotic effects of foods with beneficial effects on human health. In this study, we developed and validated a headspace solid-phase microextraction gas chromatographic–mass spectrometric method for the determination of underivatised short-chain fatty acids produced in an in vitro fermentation model. A divinylbenzene/Carboxen/polydimethylsiloxane fibre was used. Solid-phase microextraction conditions, i.e., extraction temperature, extraction time and salt addition were optimised by means of a central composite face-centred experimental design. The method was validated in terms of limit of quantification, accuracy, precision and linearity. The developed method was then applied to the analysis of short-chain fatty acids produced by the fermentation of faecal cultures derived from bread enriched with different kinds of dietary fibres.

RUMINANT NUTRITION SYMPOSIUM: Productivity, digestion, and health responses to hindgut acidosis in ruminants1

Microbial fermentation of carbohydrates in the hindgut of dairy cattle is responsible for 5 to 10% of total-tract carbohydrate digestion. When dietary, animal, or environmental factors contribute to abnormal, excessive flow of fermentable carbohydrates from the small intestine, hindgut acidosis can occur. Hindgut acidosis is characterized by increased rates of production of short-chain fatty acids including lactic acid, decreased digesta pH, and damage to gut epithelium as evidenced by the appearance of mucin casts in feces. Hindgut acidosis is more likely to occur in high-producing animals fed diets with relatively greater proportions of grains and lesser proportions of forage. In these animals, ruminal acidosis and poor selective retention of fermentable carbohydrates by the rumen will increase carbohydrate flow to the hindgut. In more severe situations, hindgut acidosis is characterized by an inflammatory response; the resulting breach of the barrier between animal and digesta may contribute to laminitis and other disorders. In a research setting, effects of increased hindgut fermentation have been evaluated using pulse-dose or continuous abomasal infusions of varying amounts of fermentable carbohydrates. Continuous small-dose abomasal infusions of 1 kg/d of pectin or fructans into lactating cows resulted in decreased diet digestibility and decreased milk fat percentage without affecting fecal pH or VFA concentrations. The decreased diet digestibility likely resulted from increased bulk in the digestive tract or from increased digesta passage rate, reducing exposure of the digesta to intestinal enzymes and epithelial absorptive surfaces. The same mechanism is proposed to explain the decreased milk fat percentage because only milk concentrations of long-chain fatty acids were decreased. Pulse-dose abomasal fructan infusions (1 g/kg of BW) into steers resulted in watery feces, decreased fecal pH, and increased fecal VFA concentrations, without causing an inflammatory response. Daily 12-h abomasal infusions of a large dose of starch (~4 kg/d) have also induced hindgut acidosis as indicated by decreased fecal pH and watery feces. On the farm, watery or foamy feces or presence of mucin casts in feces may indicate hindgut acidosis. In summary, hindgut acidosis occurs because of relatively high rates of large intestinal fermentation, likely due to digestive dysfunction in other parts of the gut. A better understanding of the relationship of this disorder to other animal health disorders is needed.

The effects of laminarin derived from Laminaria digitata on measurements of gut health: selected bacterial populations, intestinal fermentation, mucin gene expression and cytokine gene expression in the pig.

The aim of the present study was to establish the optimum inclusion level of laminarin derived from Laminaria digitata on selected microbial populations, intestinal fermentation, cytokine and mucin gene expression in the porcine ileum and colon. A total of twenty-one pigs (mean body weight 17·9kg) were randomly assigned to one of three dietary treatments: T1 - basal (control) diet, T2 and T3 - basal diets supplemented with laminarin included at 300 and 600 parts per million (ppm), respectively. Selected intestinal bacterial populations and volatile fatty acid (VFA) concentrations were measured in the ileum and colon. Relative gene expression levels for specific cytokine and mucin genes were investigated in ileal and colonic tissue in the absence and presence of a lipopolysaccharide (LPS) challenge. There was an up-regulation of MUC2 gene expression at the 300ppm inclusion level in the ileum. In the colon, there was a significant reduction in the enterobacteriaceae population at the 300ppm inclusion level (P=0·0421). Dietary supplementation of 600ppm laminarin led to a significant increase in MUC2 (P=0·0365) and MUC4 (P=0·0401) expression in the colon, and in the total VFA concentration in the caecum (P=0·0489). A significant increase was also recorded in IL-6 (P=0·0289) and IL-8 gene expression (P=0·0245) in LPS-challenged colonic tissue at both laminarin inclusion levels. In conclusion, dietary inclusion of 300ppm laminarin appears to be the optimum dose in the present study due to the reduction in the enterobacteriaceae populations and enhanced IL-6 and IL-8 cytokine expression in response to an ex vivo LPS challenge.

The effect of cereal type and enzyme supplementation on carcass characteristics, volatile fatty acids and intestinal microflora and boar taint in entire male pigs

A 2 × 2 factorial experiment was conducted to investigate the effects of cereal type (barley v. oat) and exogenous enzyme supplementation (with or without) on intestinal fermentation, and on indole and skatole levels in the intestinal content and the adipose tissue in finisher boars. The experimental treatments were as follows: (i) barley-based diet, (ii) barley-based diet with enzyme supplement, (iii) oat-based diet and (iv) oat-based diet with enzyme supplement. The enzyme supplement contained endo-1,3(4)-β-glucanase (EC 3.2.1.6) and endo-1,4-β-xylanase (EC 3.2.1.8). The animals were fed ad libitum for 45 days from 76.0 to 113.6 kg live weight. Feeding barley-based diets led to higher (P < 0.05) total volatile fatty acids concentrations in the large intestine. Proportions of propionic- and butyric-acids were higher and that of acetic acid lower in digesta from barley-based in comparison to oat-based diets (P < 0.001). Consequently, pH in the large intestine was higher after feeding oat-based in comparison to barley-based diets. Animals fed unsupplemented oat-based diet had higher (P < 0.01) indole concentrations in the digesta from the proximal colon than those fed barley-based diets. Feeding oat-based diets led to lower (P < 0.01) skatole and higher (P < 0.001) indole concentrations in the digesta from the terminal colon than barley-based diets. skatole concentrations in the adipose tissue did not differ (P > 0.05) between the experimental treatments. Pigs offered the barley-based diets had lower (P < 0.001) indole concentrations in the adipose tissue compared with those fed the oat-based diet. In conclusion, barley-based diets were more efficient than oat-based diets in limiting concentrations of indole in the adipose tissue.

Combination of in vitro intestinal continuous fermentation and intestinal cell models to investigate Salmonella and probiotics interactions in infected gut microbiota

Combination of in vitro intestinal continuous fermentation and intestinal cell models to investigate Salmonella and probiotics interactions in infected gut microbiota

Gene Expression Profiles of Colonic Mucosa in Healthy Young Adult and Senior Dogs

BackgroundWe have previously reported the effects of age and diet on nutrient digestibility, intestinal morphology, and large intestinal fermentation patterns in healthy young adult and senior dogs. However, a genome-wide molecular analysis of colonic mucosa as a function of age and diet has not yet been performed in dogs.Methodology/Principal FindingsColonic mucosa samples were collected from six senior (12-year old) and six young adult (1-year old) female beagles fed one of two diets (animal protein-based vs. plant protein-based) for 12 months. Total RNA in colonic mucosa was extracted and hybridized to Affymetrix GeneChip® Canine Genome Arrays. Results indicated that the majority of gene expression changes were due to age (212 genes) rather than diet (66 genes). In particular, the colonic mucosa of senior dogs had increased expression of genes associated with cell proliferation, inflammation, stress response, and cellular metabolism, whereas the expression of genes associated with apoptosis and defensive mechanisms were decreased in senior vs. young adult dogs. No consistent diet-induced alterations in gene expression existed in both age groups, with the effects of diet being more pronounced in senior dogs than in young adult dogs.ConclusionOur results provide molecular insight pertaining to the aged canine colon and its predisposition to dysfunction and disease. Therefore, our data may aid in future research pertaining to age-associated gastrointestinal physiological changes and highlight potential targets for dietary intervention to limit their progression.

The cellulose-degrading microbial community of the human gut varies according to the presence or absence of methanogens

Cellulose-degrading microorganisms involved in the breakdown of plant cell wall material in the human gut remain rather unexplored despite their role in intestinal fermentation. Microcrystalline cellulose-degrading bacteria were previously identified in faeces of methane-excreting individuals, whereas these microorganisms were undetectable in faecal samples from non-methane excretors. This suggested that the structure and activity of the cellulose-degrading community differ in methane- and non-methane-excreting individuals. The purpose of this study was to characterize in depth this cellulose-degrading community in individuals of both CH(4) statuses using both culture-dependent and molecular methods. A new real-time PCR analysis was developed to enumerate microcrystalline cellulose-degrading ruminococci and used to confirm the predominance of these hydrolytic ruminococci in methane excretors. Culture-dependent methods using cell wall spinach (CWS) residue revealed the presence of CWS-degrading microorganisms in all individuals. Characterization of CWS-degrading isolates further showed that the main cellulose-degrading bacteria belong essentially to Bacteroidetes in non-methane-excreting subjects, while they are predominantly represented by Firmicutes in methane-excreting individuals. This taxonomic diversity was associated with functional diversity: the ability to degrade different types of cellulose and to produce H(2) from fermentation differed depending on the species. The structure of the cellulolytic community was shown to vary depending on the presence of methanogens in the human gut.