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The global prevalence of obesity more than doubled between 1990 and 2022. By 2022, 2.5 billion adults aged 18 and older were overweight, with over 890 million of them living with obesity. The urgent need for understanding the impact of high-fat diet, together with the demanding of analytical methods with low energy/chemicals consumption, can be fulfilled by rapid, high-throughput spectroscopic techniques. To understand the impact of high-fat diet on the metabolic signatures of mouse cecal contents, we characterized metabolite variations in two diet-groups (standard vs high-fat diet) using FTIR spectroscopy and multivariate analysis. Their cecal content showed distinct spectral features corresponding to high- and low-molecular-weight metabolites. Further quantification of 13 low-molecular-weight metabolites using liquid chromatography showed significant reduction in the production of short chain fatty acids and amino acids associated with high-fat diet samples. These findings demonstrated the potential of spectroscopy to follow changes in gut metabolites., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Dietary supplemental carbohydrases are able to degrade non-starch polysaccharides and generate oligosaccharides in the gastrointestinal tract. This study was conducted to investigate the influence of dietary fiber and protein levels on growth performance, nutrient utilization, digesta oligosaccharides profile and cecal short-chain fatty acid (SCFA) profile in broilers receiving diets supplemented with xylanase or protease individually or in combination., Results: Enzyme supplementation had no effect on growth performance. There was significant (P < 0.05) fiber × protein × xylanase interaction for ileal nitrogen digestibility and significant (P < 0.01) protein × xylanase × protease interaction for nitrogen-corrected apparent metabolizable energy. Birds fed high-fiber diets had higher (P < 0.05) jejunal oligosaccharides and cecal SCFA concentrations. Xylanase and protease combination produced the greatest pentose (Pent) levels in low fiber-adequate protein diets but lowest levels in highfiber-low protein diets. There was significant (P < 0.05) fiber × xylanase × protease interaction explained by the digesta concentrations of (Pent) 3 , (Pent) 4 and (Pent) 5 being greatest (P < 0.5) in protease-only supplemented high-fiber diets but lowest in protease-only supplemented low-fiber diets., Conclusion: These results suggest that, of all the factors investigated, dietary fiber level had the greatest effect on modulating digesta concentration of oligosaccharides and cecal SCFA. Evidence points to the fact that there is considerable capacity for generating pentose oligosaccharides in the digestive tract of broilers receiving diets rich in fibrous feedstuffs, and that this may have a beneficial effect on microbial profile in the digestive tract. © 2021 Society of Chemical Industry., (© 2021 Society of Chemical Industry.)

The prebiotic effect of high β-glucan barley (HGB) flour on the innate immune system of high-fat model mice was investigated. C57BL/6J male mice were fed a high-fat diet supplemented with HGB flour for 90 days. Secretory immunoglobulin A (sIgA) in the cecum and serum were analyzed by enzyme-linked immunosorbent assays (ELISA). Real-time PCR was used to determine mRNA expression levels of pro- and anti-inflammatory cytokines such as interleukin (IL)-10 and IL-6 in the ileum as well as the composition of the microbiota in the cecum. Concentrations of short-chain fatty acids (SCFAs) and organic acids were analyzed by GC/MS. Concentrations of sIgA in the cecum and serum were increased in the HGB group compared to the control. Gene expression levels of IL-10 and polymeric immunoglobulin receptor ( pIgR ) significantly increased in the HGB group. HGB intake increased the bacterial count of microbiota, such as Bifidobacterium and Lactobacillus . Concentrations of propionate and lactate in the cecum were increased in the HGB group, and a positive correlation was found between these organic acids and the IL-10 expression level. Our findings showed that HGB flour enhanced immune function such as IgA secretion and IL-10 expression, even when the immune system was deteriorated by a high-fat diet. Moreover, we found that HGB flour modulated the gut microbiota, which increased the concentration of SCFAs, thereby stimulating the immune system.

Effects of dietary supplemental stachyose on caecal skatole concentration, hepatic cytochrome P450 (CYP450, CYP) mRNA expressions and enzymatic activities in broilers were evaluated. Arbor Acre commercial mixed male and female chicks were assigned randomly into six treatments. The positive control (PC) diet was based on maize-soyabean meal, and the negative control (NC) diet was based on maize-non-soyabean meal. The NC diet was then supplemented with 4, 5, 6 and 7 g/kg stachyose to create experimental diets, named S-4, S-5, S-6 and S-7, respectively. Each diet was fed to six replicates of ten birds from days 1 to 49. On day 49, the caecal skatole concentrations in the PC, S-4, S-5, S-6 and S-7 groups were lower than those in the NC group by 42·28, 23·68, 46·09, 15·31 and 45·14 % (P < 0·01), respectively. The lowest pH value was observed in the S-5 group (P < 0·05). The stachyose-fed groups of broilers had higher caecal acetate and propionate levels compared with control groups, and propionate levels in the S-6 and S-7 groups were higher than those in the S-4 and S-5 groups (P < 0·001). The highest CYP3A4 expression was found in the S-7 group (P < 0·05), but this was not different from PC, S-4, S-5 and S-6 treatments. There was no significant difference in CYP450 (1A2, 2D6 and 3A4) enzymatic activities among the groups (P > 0·05). In conclusion, caecal skatole levels can be influenced by dietary stachyose levels, and 5 g/kg of stachyose in the diet was suggested.

Scope: The possible mechanisms of production of four novel resistant starch type 4 (RS4) products for total cecal fermentation in an in vivo rodent model are evaluated., Methods and Results: Forty weanling rats are randomly assigned to five groups (n = 8) for a 3-week study. Starches are the RS type 4 products, as 10% of weight of RS diets (RSA-RSD), and AMIOCA starch (100% amylopectin) comprises 53.6% weight of control (CON) and 43.6% weight of RS diets. The RS products vary by percent purity and origin (potato, corn, tapioca). At euthanasia, cecal contents, serum, GI tract, and abdominal fat are collected. RSB, RSC, and RSD fed rats have greater empty cecum weights, lower cecal content pH, higher cecal content wet weight, and higher total cecal content acetate and propionate than the CON and RSA fed rats. Two other indicators of fermentation, total cecal contents butyrate and glucagon-like peptide 1, do not have significant ANOVA F values, which require more subjects for 80% power., Conclusion: RS4 products that are produced from different starch origins with varying amounts of RS4 content and different methods of production are not uniformly fermented in an in vivo model., (© 2019 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Biochemical effects of the water soluble fiber fraction of sugarcane bagasse (BSF) fermented in the colon was examined to evaluate its potential health promoting effects. A feeding experiment involving Fischer 344 rats, was conducted with 3 experimental diets containing, cellulose (CON), a commercial xylo-oligosaccharide (XYO) and BSF (BGS). Cumulative feed intake was significantly lower in XYO group while cecal weight was significantly higher. Acetic and propionic acid contents in the cecal content were significantly higher in the BGS and XYO, respectively. Total short chain fatty acid content was significantly higher in BGS and XYO resulting significantly lower cecal pH. Beneficial bacteria such as Bifidobacterium, Blautia, Akkermansia and Roseburia abundance was significantly higher in the XYO and BGS groups. Further, mucin and immunoglobulin-A contents were significantly higher in BGS group compared to CON group. Thus, BSF exhibited its ability to enhance the intestinal and systemic health upon fermentation in the colon., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

In this study, we validated a method for quantifying 20 tryptophan (Trp) catabolites by liquid chromatography coupled with high resolution mass spectrometry (LC-HRMS) in 4 different matrices (urine, serum, intestinal contents and liver). The detection limit for all metabolites ranged between 0.015 and 11.25 nmol/L and the dynamic range of the calibration curves were adjusted to allow quantification of metabolites at endogenous levels. Matrix effects were evaluated using isotope labeled internal standards. Reproducibility in the 4 matrices was characterized by CV = 6.2% with an accuracy of 6.6%. Our method has been applied to the determination and quantification of 20 metabolites concentrations in 5 different mouse compartments (plus cecal contents). Our results show that our approach allows for a global exploration of the Trp metabolism by quantifying a large number of Trp metabolites, at the individual level by multi-matrix approach., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Linaclotide is efficacious in the management of irritable bowel syndrome with constipation (IBS-C), yet relatively little is known regarding its effect on human gastrointestinal physiology. The primary aim of the study was to examine the effect of linaclotide on change in pH across the ileocecal junction (ICJ), a proposed measure of cecal fermentation, and its relationship to symptoms and quality of life (QoL) in IBS-C., Methods: A total of 13 participants with Rome III IBS-C underwent a standardized wireless motility capsule (WMC). Stool consistency was measured using the Bristol stool form scale (BSFS) and frequency with spontaneous bowel movements (SBM). Gastrointestinal symptoms and QoL were assessed using validated questionnaires. The WMC and questionnaires were repeated after 28 days of linaclotide 290 g po od., Key Results: Linaclotide reduced the change in pH across the ICJ (-2.4 ± 0.2 vs -2.1 ± 0.4, P = 0.01) as a function of a relative alkalinization of the cecum (5.2 ± 0.2 vs 5.5 ± 0.3, P = 0.02). Linaclotide accelerated colonic transit time (2650 minutes (2171-4038) vs. 1757 (112-3011), P = 0.02), increased colonic log motility index (15 ± 1.8 vs. 16.5 ± 1.8, P = 0.004) but had no effect of gastric emptying or small bowel transit. Change in pH across the ICJ correlated with improvement in symptom intensity, unpleasantness, and visceral sensitivity index (r = 0.62, P = 0.03, r = 0.63, P = 0.02, r = 0.62, P = 0.02) and with increases in BSFS type and SBM (r = 0.9, P < 0.0001, r = 0.6, P = 0.02)., Conclusions & Inferences: Linaclotide's effects are confined to the colon where it increases cecal pH, potentially representing a reduction in cecal fermentation and accelerates colonic motility., (© 2018 John Wiley & Sons Ltd.)

Campylobacter jejuni is a pathogenic bacterium that causes gastroenteritis in humans yet is a widespread commensal in wild and domestic animals, particularly poultry. Using RNA sequencing, we assessed C. jejuni transcriptional responses to medium supplemented with human fecal versus chicken cecal extracts and in extract-supplemented medium versus medium alone. C. jejuni exposed to extracts had altered expression of 40 genes related to iron uptake, metabolism, chemotaxis, energy production, and osmotic stress response. In human fecal versus chicken cecal extracts, C. jejuni displayed higher expression of genes involved in respiration ( fdhTU ) and in known or putative iron uptake systems ( cfbpA , ceuB , chuC , and CJJ81176&#95;1649-1655 [here designated 1649-1655 ]). The 1649-1655 genes and downstream overlapping gene 1656 were investigated further. Uncharacterized homologues of this system were identified in 33 diverse bacterial species representing 6 different phyla, 21 of which are associated with human disease. The 1649 and 1650 ( p19 ) genes encode an iron transporter and a periplasmic iron binding protein, respectively; however, the role of the downstream 1651-1656 genes was unknown. A Δ 1651 - 1656 deletion strain had an iron-sensitive phenotype, consistent with a previously characterized Δ p19 mutant, and showed reduced growth in acidic medium, increased sensitivity to streptomycin, and higher resistance to H 2 O 2 stress. In iron-restricted medium, the 1651-1656 and p19 genes were required for optimal growth when using human fecal extracts as an iron source. Collectively, this implicates a function for the 1649-1656 gene cluster in C. jejuni iron scavenging and stress survival in the human intestinal environment. IMPORTANCE Direct comparative studies of C. jejuni infection of a zoonotic commensal host and a disease-susceptible host are crucial to understanding the causes of infection outcome in humans. These studies are hampered by the lack of a disease-susceptible animal model reliably displaying a similar pathology to human campylobacteriosis. In this work, we compared the phenotypic and transcriptional responses of C. jejuni to intestinal compositions of humans (disease-susceptible host) and chickens (zoonotic host) by using human fecal and chicken cecal extracts. The mammalian gut is a complex and dynamic system containing thousands of metabolites that contribute to host health and modulate pathogen activity. We identified C. jejuni genes more highly expressed during exposure to human fecal extracts in comparison to chicken cecal extracts and differentially expressed in extracts compared with medium alone, and targeted one specific iron uptake system for further molecular, genetic, and phenotypic study., (Copyright © 2018 Liu et al.)

Susceptibility to Clostridium difficile infection (CDI) is primarily associated with previous exposure to antibiotics, which compromise the structure and function of the gut bacterial community. Specific antibiotic classes correlate more strongly with recurrent or persistent C. difficile infection. As such, we utilized a mouse model of infection to explore the effect of distinct antibiotic classes on the impact that infection has on community-level transcription and metabolic signatures shortly following pathogen colonization and how those changes may associate with persistence of C. difficile Untargeted metabolomic analysis revealed that C. difficile infection had significantly larger impacts on the metabolic environment across cefoperazone- and streptomycin-pretreated mice, which became persistently colonized compared to clindamycin-pretreated mice, where infection quickly became undetectable. Through metagenome-enabled metatranscriptomics, we observed that transcripts for genes associated with carbon and energy acquisition were greatly reduced in infected animals, suggesting that those niches were instead occupied by C. difficile Furthermore, the largest changes in transcription were seen in the least abundant species, indicating that C. difficile may "attack the loser" in gut environments where sustained infection occurs more readily. Overall, our results suggest that C. difficile is able to restructure the nutrient-niche landscape in the gut to promote persistent infection. IMPORTANCE Clostridium difficile has become the most common single cause of hospital-acquired infection over the last decade in the United States. Colonization resistance to the nosocomial pathogen is primarily provided by the gut microbiota, which is also involved in clearing the infection as the community recovers from perturbation. As distinct antibiotics are associated with different risk levels for CDI, we utilized a mouse model of infection with 3 separate antibiotic pretreatment regimens to generate alternative gut microbiomes that each allowed for C. difficile colonization but varied in clearance rate. To assess community-level dynamics, we implemented an integrative multi-omics approach that revealed that infection significantly changed many aspects of the gut community. The degree to which the community changed was inversely correlated with clearance during the first 6 days of infection, suggesting that C. difficile differentially modifies the gut environment to promote persistence. This is the first time that metagenome-enabled metatranscriptomics have been employed to study the behavior of a host-associated microbiota in response to an infection. Our results allow for a previously unseen understanding of the ecology associated with C. difficile infection and provide the groundwork for identification of context-specific probiotic therapies., (Copyright © 2018 Jenior et al.)

Short-chain fatty acids, the end products of fermentation of dietary fibers by the gut microbiota, have been shown to exert multiple effects on mammalian metabolism. For the analysis of short-chain fatty acids, gas chromatography-mass spectrometry is a very powerful and reliable method. Here, we describe a fast, reliable, and reproducible method for the separation and quantification of short-chain fatty acids in mouse feces, cecum content, and blood samples (i.e., plasma or serum) using gas chromatography-mass spectrometry. The short-chain fatty acids analyzed include acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, and heptanoic acid.

The effects of two types of mushroom (Agaricus bisporus; white, WM; brown, BM) powders on intestinal fermentation in rats were investigated in terms of the physical characteristics of animals and by bacterial and HPLC analyses of cecal contents. Short-chain fatty acid levels were found to be significantly higher in the WM group than in the BM and the control (CN) groups; coliform bacteria levels in the BM group were significantly lower than those in the CN group, with the WM group inducing an apparent but insignificant decrease in coliforms. Anaerobe levels in the WM group were significantly higher than those in the CN group and, compared with the CN group, the BM and WM groups exhibited significantly increased feces weight and cecum weight, respectively. These results indicate that the mushroom powders, and in particular the WM powder, have beneficial effects on the intestinal environment in rats.

Sphingolipids from marine sources have attracted more attention recently because of their distinctive structures and expected functions. In this study, the content and components of cerebroside from sea cucumber Stichopus japonicus were analyzed. The absorption of cerebroside from S. japonicus was investigated with an in vivo lipid absorption assay. The result revealed that S. japonicus is a rich source of cerebroside that contained considerable amounts of odd carbon chain sphingoid bases. The cumulative recoveries of d17:1- and d19:2-containing cerebrosides were 0.31 ± 0.16 and 0.32 ± 0.10%, respectively, for 24 h after administration. To the best of the authors' knowledge, this is the first work that shows sphingolipids from a marine source could be absorbed in vivo and incorporated into ceramides. In addition, dietary supplementation with sea cucumber cerebroside to hairless mouse improved the skin barrier function and increased short-chain fatty acids in cecal contents, which have shown beneficial effects on the host.

Functional capacity of digestive system and intestinal adaptive immunity are immature at hatching of broiler chicks. Therefore, intestinal innate immunity after hatching is vital to young chicks. The purpose of this study was to investigate expression and tissue distributions of several elements of the innate immune system (i.e., TLR2, TLR4, CD83, and MHC class II expressing cells) in the intestine of one-day-old chicks. For this purpose, ileum and cecum were examined the under different conditions, which included the control and 1, 3, 6, 12, or 24 h after injection of lipopolysaccharide (LPS) and phosphate buffered saline. The findings indicated that regardless of the antigenic stimulation, Toll-like receptor (TLR) 2 and TLR4 expressing cells were present in the intestinal tissues of one-day-old chicks. We noticed that the intestinal segments have different TLR expression levels after LPS stimulation. Dendritic cells were identified, and they left the intestinal tissue after LPS treatment. MHC class II molecules were diffusely present in both the ileum and cecum. This study demonstrates that the intestinal tissue of one-day-old chicks has remarkable defensive material, including histological properties and several elements of the innate immune system. Microsc. Res. Tech. 79:604-614, 2016. © 2016 Wiley Periodicals, Inc., (© 2016 Wiley Periodicals, Inc.)

Lactobacilli have been associated with a variety of immunomodulatory effects and some of these effects have been related to changes in gastrointestinal microbiota. However, the relationship between probiotic dose, time since probiotic consumption, changes in the microbiota, and immune system requires further investigation. The objective of this study was to determine if the effect of Lactobacillus casei 32G on the murine gastrointestinal microbiota and immune function are dose and time dependent. Mice were fed L. casei 32G at doses of 106, 107, or 108 CFU/day/mouse for seven days and were sacrificed 0.5h, 3.5h, 12h, or 24h after the last administration. The ileum tissue and the cecal content were collected for immune profiling by qPCR and microbiota analysis, respectively. The time required for L. casei 32G to reach the cecum was monitored by qPCR and the 32G bolus reaches the cecum 3.5h after the last administration. L. casei 32G altered the cecal microbiota with the predominance of Lachnospiraceae IS, and Oscillospira decreasing significantly (p < 0.05) in the mice receiving 108 CFU/mouse 32G relative to the control mice, while a significant (p < 0.05) increase was observed in the prevalence of lactobacilli. The lactobacilli that increased were determined to be a commensal lactobacilli. Interestingly, no significant difference in the overall microbiota composition, regardless of 32G doses, was observed at the 12h time point. A likely explanation for this observation is the level of feed derived-nutrients resulting from the 12h light/dark cycle. 32G results in consistent increases in Clec2h expression and reductions in TLR-2, alpha-defensins, and lysozyme. Changes in expression of these components of the innate immune system are one possible explanation for the observed changes in the cecal microbiota. Additionally, 32G administration was observed to alter the expression of cytokines (IL-10rb and TNF-α) in a manner consistent with an anti-inflammatory response.

Zinc oxide (ZnO) used in high ('pharmacological') levels to prevent diarrhoea in pigs is assumed to reduce copper (Cu) in tissues and inhibits large intestinal microbial fermentation. To test it, German Landrace pigs were weaned on d28 of age and fed diets containing either 100 (LowZinc, LZn, n = 10) or 3100 mg ZnO/kg (HighZinc, HZn, n = 10). The mixed feed (13.0 MJ ME, 18.5% crude protein) was based on wheat, barley, soya bean meal and maize. After 4 weeks, the HZn group was further fed 100 mg ZnO/kg for another 2 weeks. Caecal contents, faeces and tissues were collected after 4 weeks (n = 5 and n = 10 respectively) and 6 weeks (n = 5 and n = 5 respectively). Faeces and caecal content were analysed for dry matter (DM), pH, ammonia, lactic acid (LA) and short-chain fatty acids (SCFA) on native water basis. anova was performed to elucidate significant differences at p < 0.05. No diarrhoea occurred. After 4 weeks, the caecal contents' pH increased (p < 0.001) and butyric (p < 0.05) and valeric acid (p < 0.01) decreased in the HZn group in comparison with LZn. In faeces, a decrease of acetic (p = 0.009), butyric (p = 0.007) and valeric acid (p = 0.046), as well as reduced acetic:propionic acid (A:P) ratio (p = 0.025) was observed in the HZn group in comparison with LZn. Faecal ammonia decreased in HZn (p = 0.018). No differences (p > 0.05) were recorded in caecal contents after 6 weeks. In faeces, acetic acid remained lower in the HZn group in comparison with LZn (p = 0.006), as did the A:P ratio (p = 0.004). Zn concentration in liver, kidneys and ribs, and Cu concentrations in kidneys increased in HZn. Withdrawal of ZnO resulted in reversibility of the changes. The effect on butyric acid should be discussed critically regarding the energetic support for the enterocytes. High Zn and Cu tissue concentrations should be considered by pet food producers., (Journal of Animal Physiology and Animal Nutrition © 2015 Blackwell Verlag GmbH.)

The effect of high-grain (HG) feeding on caecal bacterial microbiota composition and fermentation and mucosa health is largely unknown. In the present study, ten male goats were randomly assigned to either a group fed a hay diet (0 % grain; n 5) or a group fed a HG diet (65 % grain; n 5) to characterise the changes in the composition of the bacterial community and mucosal morphology in the caecum. After 7 weeks of feeding, the HG diet decreased the caecal pH (P< 0·001) and increased (P< 0·001 to P< 0·004) the caecal digesta concentrations of total volatile fatty acids and lipopolysaccharide (LPS). Pyrosequencing of the 16S ribosomal RNA gene revealed that HG feeding increased (P= 0·001 to P= 0·009) the abundance of predominant genera Turicibacter and Clostridium in the caecal lumen and in the caecal mucosa and decreased (P< 0·001 to P< 0·009) the proportion of Bacteroides in the lumen and Mucispirillum in the mucosa compared with the hay diet. Furthermore, the HG diet-fed goats exhibited intense epithelial damage and up-regulation (P< 0·001 to P< 0·025) of the relative mRNA expression of IL-1β, IL-6, IL-12 and interferon-γ (IFN-γ) in the caecal mucosa. The correlation analysis revealed that alterations in caecal pH, LPS concentration and mucosa-associated microbiota abundance during HG feeding might partly contribute to local inflammation. Collectively, these results provide insight into the adaptive response of caecal bacterial populations to HG feeding in goats and reveal that the fermentable substrates that flow into the caecum may cause dramatic alterations in microbial compositions and play a significant role in caecal dysfunction.

This study demonstrated that 0.5% dietary rutin, ellagic acid, or curcumin markedly increased cecal succinate levels in rats fed a high-fat diet, whereas catechin, caffeic acid, and quercetin did not. Other organic acids were modestly or hardly affected by polyphenols. To clarify the effects of succinate levels increased by polyphenols, this study examined the effects of succinate on the growth and proliferation of colon cancer cells and angiogenesis. The growth and proliferation of HT29 human colon cancer cells and angiogenesis in an ex vivo model were significantly inhibited by succinate at a dose close to that in the cecum of rats fed polyphenols. Furthermore, succinate inhibited the migration of human umbilical vein endothelial cells. These findings suggest that the consumption of some polyphenols affects the health and diseases of the large intestine by elevating succinate.

Dietary fiber/starch imbalance can lead to diarrhea in rabbits. However, the underlying molecular mechanisms are largely unknown, and this is the first study on the proteome profile of the cecal tissue of diarrheic rabbits. In this study, one group of weanling rabbits was fed a high fiber/starch diet (control group), and another group was fed a low fiber/starch diet (diarrhea group). We applied 2-D gel electrophoresis, coupled with histological and biochemical analyses, to study dynamic changes in the proteome of the cecal tissue from healthy and diarrheic growing rabbits. We identified 29 protein spots showing differential abundance between the two groups. We identified the proteins and found that they participated in key biological processes, including absorption, digestion and transport; cell structure and motility; inflammatory response; glucose and energy metabolism; mineral and vitamin metabolism; stress response and cell redox homeostasis. Moreover, the results of our proteomics analysis revealed continuous impairment and compensatory intestinal repair in the rabbits with diarrhea. Therefore, these findings shed light on the main mechanisms and the main proteins involved in intestinal degradation in diarrhea. These findings have important implications for understanding the mechanism of cecal damage and repair in diarrhea in rabbits caused by dietary factors., Biological Significance: The different cecal protein expressions were compared between healthy and diarrhea in growing rabbit model fed different fiber/starch diets. Diarrhea caused by feeding high-starch diet induced mucosal injury and inflammation. In this work we identify protein spots by MALDI-TOF MS and classify by biological function. The finding that the expression of all other proteins belonging to seven functional groups was significantly increased in the diarrheic rabbits, except for CMBL, suggests that many intestinal functional proteins may be related to up-regulation, such as cell absorption, digestion, transport, structure, motility, metabolism (including energy mineral and vitamin), inflammatory response, stress response, and redox homeostasis in diarrhea., (Copyright © 2014 Elsevier B.V. All rights reserved.)

To clarify the effect of type of foods on the intestinal environment, Far East Asian- (FEA; rich in rice starch, soy protein and soy oil) and Far East Asian marine- (FEAM; rich in rice starch, fish meal, fish oil and brown alga) modelled diets and sucrose, casein and beef tallow-rich (SCB) diet were prepared. After the 2-week administration of diets in rats, caecal organic acids and putrefactive compounds (ammonia, indole, phenol and H2S, which are regarded as putative risk factors for tumours) were determined. The caecal microbiota was also analyzed using denaturing gradient gel electrophoresis and pyrosequencing with bar-coded primers targeting the bacterial 16S rRNA gene. Levels of n-butyrate, acetate, indole and phenol were high in rats fed FEA. On the other hand, H2S was clearly suppressed by both FEA and FEAM comparing with SCB. These results suggest that FEAM is preferable to FEA for optimal intestinal environment and host health. Both microbial analyses showed that the diversity of microbiota in the FEAM group was lower than in the other diet groups. Ratio of Firmicutes, Bacteroidetes and Proteobacteria in the SCB group was about 5:4:1. Firmicutes, particularly Lachnospiraceae, was promoted by FEA and FEAM.

It is widely established that a high-protein fishmeal supplemented starter diet and Eimeria infection can predispose birds to the development of clinical necrotic enteritis symptoms following Clostridium perfringens infection. However, it has not been clearly established what changes these treatments cause to predispose birds to succumb to necrotic enteritis. We analysed caecal microbiota of 4 groups of broilers (n=12) using deep pyrosequencing of 16S rDNA amplicons: (1) control chicks fed a control diet, (2) Eimeria infected chicks fed control diet, (3) chicks fed fishmeal supplemented diet and lastly (4) both fishmeal fed and Eimeria infected chicks. We found that the high-protein fishmeal diet had a strong effect on the intestinal microbiota similar to the previously reported effect of C. perfringens infection. We noted major changes in the prevalence of various lactobacilli while the total culturable Lactobacillus counts remained stable. The Ruminococcaceae, Lachnospiraceae, unknown Clostridiales and Lactobacillaceae families were most affected by fishmeal with increases in a number of operational taxonomic units (OTUs) that had previously been linked to Crohn's disease and reductions in OTUs known to be butyrate producers. Eimeria induced very different changes in microbiota; Ruminococcaceae groups were reduced in number and three unknown Clostridium species were increased in abundance. Additionally, Eimeria did not significantly influence changes in pH, formic, propionic or isobutyric acid while fishmeal induced dramatic changes in all these measures. Both fishmeal feeding and Eimeria infection induced significant changes in the gut microbiota; these changes may play an important role in predisposing birds to necrotic enteritis., (Copyright © 2014 Elsevier B.V. All rights reserved.)

To clarify the effect of soy protein (SP) and fish meal (FM), compared to milk casein (MC), on the intestinal environment, we examined caecal environment of rats fed the test diets. Four-week-old rats were fed AIN-76-based diet containing 20 %, w/w MC, SP or FM for 16 days. Caecal organic acids were analysed by HPLC. Caecal putrefactive compounds (indole, phenol, H2S and ammonia) were analysed by colorimetric assays. Caecal microflora was determined by 16S rRNA gene-DGGE and pyrosequencing with bar-coded primers targeting the bacterial 16S rRNA gene. n-Butyric and lactic acid levels were high in rats fed SP and FM, respectively. Butyrate-producing bacteria, such as Oscillibacter, and lactate-producing bacteria, such as Lactobacillus, were detected in each diet group. Also, the putrefactive compound contents were high in rats fed SP and FM. In this study, both DGGE and pyrosequencing analyses were able to evaluate the dynamics of the intestinal microbiota. The results indicate that dietary proteins can alter the intestinal environment, affecting fermentation by the intestinal microbiota and the generation of putrefactive compounds.

Gut bacteria influence host anatomy and physiology. It has been proposed that bacterial metabolites including polyamines are responsible for intestinal maturation and mucosal growth. We have hypothesised that bacterially produced polyamines act as trophic factors and thereby influence large intestinal crypt depth and thickness of the different gut layers. For that purpose, germ-free mice were associated with two different microbial consortia. One group was colonised with a simplified human microbiota (SIHUMI). The second group was associated with SIHUMI + Fusobacterium varium (SIHUMI + Fv), which is known to produce high amounts of polyamines. Polyamine concentrations were measured by HPLC and morphological parameters were determined microscopically. Germ-free and conventional mice served as controls. The caecal putrescine concentration of the SIHUMI + Fv was 61.8 μM (47.6-75.5 μM), whereas that of conventional and SIHUMI mice was 28.8 μM (1.3-41.7 μM) and 24.5 μM (16.8-29.1 μM), respectively. The caecal putrescine concentration of germ-free mice was only 0.6 μM (0-1.0 μM). Caecal crypt depth and thickness of the different caecal layers revealed no significant differences between SIHUMI and SIHUMI + Fv mice. However, the crypt depth in the caeca of conventional, SIHUMI and SIHUMI + Fv mice was increased by 48.6% (P<0.001), 39.7% (P<0.001) and 28.5% (P<0.05), respectively, compared to germ-free mice. These findings indicate that increased intestinal putrescine concentrations do not influence gut morphology in our gnotobiotic adolescent mice.

Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) qualitatively and quantitatively measured resistant starch (RS) in rat cecal contents. Fisher 344 rats were fed diets of 55% (w/w, dry basis) starch for 8 weeks. Cecal contents were collected from sacrificed rats. A corn starch control was compared against three RS diets. The RS diets were high-amylose corn starch (HA7), HA7 chemically modified with octenyl succinic anhydride, and stearic-acid-complexed HA7 starch. To calibrate the FTIR-PAS analysis, samples from each diet were analyzed using an enzymatic assay. A partial least-squares cross-validation plot generated from the enzymatic assay and FTIR-PAS spectral results for starch fit the ideal curve with a R(2) of 0.997. A principal component analysis plot of components 1 and 2 showed that spectra from diets clustered significantly from each other. This study clearly showed that FTIR-PAS can accurately quantify starch content and identify the form of starch in complex matrices.

This study investigated the effects of dietary supplementation with burdock powder and Aspergillus awamori-fermented burdock powder at 5% on the intestinal luminal environment and body fat in rats fed a high-fat (HF) diet. Food intake and growth were unaffected by dietary manipulation. Consumption of the burdock and fermented burdock diets significantly elevated fecal IgA and mucins (indices of intestinal immune and barrier functions) and reduced fecal lithocholic acid (a risk factor for colon cancer) (p<0.05). The fermented burdock diet markedly elevated cecal Bifidobacterium and organic acids, including lactate, acetate, propionate, and butyrate, and reduced fecal deoxycholic acid (a risk factor for colon cancer) and perirenal adipose tissue weight (p<0.05), but the burdock diet did not. These results suggest that consumption of fermented burdock improves the intestinal luminal environment and suppresses obesity in rats fed a HF diet.

To identify Escherichia coli proteins involved in adaptation to intestinal inflammation, mice were monoassociated with the colitogenic E. coli strain UNC or with the probiotic E. coli strain Nissle. Intestinal inflammation was induced by treating the mice with 3.5% dextran sodium sulfate (DSS). Differentially expressed proteins in E. coli strains collected from cecal contents were identified by 2-dimensional difference gel electrophoresis. In both strains, acute inflammation led to the downregulation of pathways involved in carbohydrate breakdown and energy generation. Accordingly, DSS-treated mice had lower concentrations of bacterial fermentation products in their cecal contents than control mice. Differentially expressed proteins also included the Fe-S cluster repair protein NfuA, the tryptophanase TnaA, and the uncharacterized protein YggE. NfuA expression was 3-fold higher in E. coli strains from DSS-treated than from control mice. Reporter experiments confirmed the induction of nfuA in response to iron deprivation, mimicking Fe-S cluster destruction by inflammation. YggE expression, which has been reported to reduce the intracellular level of reactive oxygen species, was 4- to 8-fold higher in E. coli Nissle than in E. coli UNC. This was confirmed by in vitro reporter gene assays indicating that Nissle is better equipped to cope with oxidative stress than UNC. Nissle isolated from DSS-treated and control mice had TnaA levels 4- to 7-fold-higher than those of UNC. Levels of indole resulting from the TnaA reaction were higher in control animals associated with E. coli Nissle. Because of its anti-inflammatory effect, indole is hypothesized to be involved in the extension of the remission phase in ulcerative colitis described for E. coli Nissle.

To evaluate the effect of mannan-oligosaccharides (MOS) on in vivo performance, nutrient digestibility, fermentation characteristics and caecal microbial populations of rabbits, 144 thirty-five days old hybrid Hyla were equally divided into three groups, one of which was fed the same diet without additives (control group), one with antibiotics (colistin sulphate, 144 mg/kg; tylosin, 100 mg/kg; oxytetracyclin, 1000 mg/kg) and one with MOS (1 g/kg of diet). Mortality rate, live weight, feed intake and feed conversion ratio were recorded up to 62 days of age. At 60 days nutrient digestibility was measured by acid insoluble ash method. The caecal content of 10 rabbits per group was collected at 62 days and analysed for volatile fatty acids production, ammonia content and microbial count. Rabbits from the control group had a significantly (p < 0.01) lower body weight at 62 days (1638.9 g vs. 1779.4 g and 1862.5 g, respectively for the control, MOS and antibiotic groups) while the antibiotic group showed a higher (p < 0.05) feed intake than the control group (127.9 g/day vs. 109.3 g/day). Rabbits from the MOS group had a higher apparent digestibility of cellulose (34.27% vs. 29.61% and 27.49%, respectively for the MOS, control and antibiotic groups) and, as a consequence a higher level of acetate in the caecal content (39.93 mmol/l vs. 34.21 mmol/l and 23.09 mmol/l, respectively for the MOS, control and antibiotic groups). Caecal microflora of the MOS group rabbits also had a higher fermentative activity in respect of protein source, as demonstrated by the higher productions of branched chain fatty acids. MOS and antibiotics significantly reduced the colonies of Coliformis (2.32 vs. 3.20 vs. 2.40 logCFU/g, respectively for the MOS, control and antibiotic groups, p < 0.01). Mannan-oligosaccharides at 1 g/kg of diet can be used as an alternative to antibiotics during the rabbit's growth period., (© 2011 Blackwell Verlag GmbH.)

Procyanidins, as important secondary plant metabolites in fruits, berries, and beverages such as cacao and tea, are supposed to have positive health impacts, although their bioavailability is yet not clear. One important aspect for bioavailability is intestinal metabolism. The investigation of the microbial catabolism of A-type procyanidins is of great importance due to their more complex structure in comparison to B-type procyanidins. A-type procyanidins exhibit an additional ether linkage between the flavan-3-ol monomers. In this study two A-type procyanidins, procyanidin A2 and cinnamtannin B1, were incubated in the pig cecum model to mimic the degradation caused by the microbiota. Both A-type procyanidins were degraded by the microbiota. Procyanidin A2 as a dimer was degraded by about 80% and cinnamtannin B1 as a trimer by about 40% within 8 h of incubation. Hydroxylated phenolic compounds were quantified as degradation products. In addition, two yet unknown catabolites were identified, and the structures were elucidated by Fourier transform mass spectrometry.

The effects of a grain-based subacute ruminal acidosis (SARA) challenge (GBSC) and an alfalfa-pellet SARA challenge (APSC) on fermentation and endotoxins in the rumen and in the cecum, as well as on endotoxins in peripheral blood, were determined. Six nonlactating Holstein cows with cannulas in the rumen and cecum were used in the study. A 3×3 Latin square arrangement of treatments with 4-wk experimental periods was adopted. During the first 3 wk of each experimental period, all cows received a diet containing 70% forages [dry matter (DM) basis]. In wk 4 of each period, cows received 1 of the following 3 diets: the 70% forage diet fed during wk 1 to 3 (control), a diet in which 34% of the dietary DM was replaced with grain pellets made of 50% ground wheat and 50% ground barely (GBSC), or a diet in which 37% of dietary DM was replaced with pellets of ground alfalfa (APSC). Rumen pH was monitored continuously using indwelling pH probes, and rumen fluid, blood, cecal digesta, and fecal grab samples were collected immediately before feed delivery at 0900 h and at 6 h after feed delivery on d 3 and 5 of wk 4. The time for which rumen pH was below 5.6 was 56.4, 225.2, and 298.8 min/d for the control, APSC, and GBSC treatments, respectively. Compared with the control, SARA challenges resulted in similar reductions in cecal digesta pH, which were 7.07, 6.86, and 6.79 for the control, APSC, and GBSC treatments, respectively. Compared with the control, only GBSC increased starch content in cecal digesta, which averaged 2.8, 2.6, and 7.4% of DM for the control, APSC, and GBSC, respectively. Free lipopolysaccharide endotoxin (LPS) concentration in rumen fluid increased from 10,405 endotoxin units (EU)/mL in the control treatment to 30,715 and 168,391 EU/mL in APSC and GBSC, respectively. Additionally, GBSC increased the LPS concentration from 16,508 to 118,522 EU/g in wet cecal digesta, and from 12,832 to 93,154 EU/g in wet feces. The APSC treatment did not affect LPS concentrations in cecal digesta and feces. All concentrations of LPS in blood plasma were below the detection limit of >0.05 EU/mL of the technique used. Despite the absence of LPS in blood, only GBSC increased the concentration of LPS-binding protein in blood plasma, which averaged, 8.9, 9.5, and 12.1mg/L for the control, APSC, and GBSC treatments, respectively. This suggests that GBSC caused translocation of LPS from the digestive tract but that LPS was detoxified before entering the peripheral blood circulation. The higher LPS concentration in cecal digesta in the GBSC compared with the APSC suggests a higher risk of LPS translocation in the large intestine in GBSC than in APSC., (Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

The study aimed to describe the interactions between nutrition and caecal bacteria abundance using odd-numbered and branched-chain fatty acids (OBCFA). Following a 2 × 2 factorial design, 47 rabbits were fed diets with two levels of digestible fibre (DF, 180 vs. 260 g/kg DM) supplemented with soybean oil (SO, 20 g/kg) or not. At 77 days of age, fatty acid (FA) composition was determined in caecal contents. The microbial origin of OBCFA vs. dietary FA in caecal contents was illustrated by clustering of these FA in the loading plots of principal component analysis. The contribution of odd-numbered FA in the OBCFA pattern was increased (p < 0.05) for high DF diets, whereas that of branched-chain FA decreased (p < 0.05), indicating potential shifts in the relative abundance of Gram-negative and Gram-positive fibrolytic bacteria respectively. Soybean oil reduced the relative importance of OBCFA (p < 0.001) in total microbial FA; however, its effects appeared to depend on the readily available fermentable substrate, as indicated by the DF × SO interactions (p < 0.001). In conclusion, OBCFA may be potentially used as markers of caecum function, but further detailed studies are necessary to validate their use as diagnostic tools in rabbit nutrition., (© 2010 Blackwell Verlag GmbH.)

Lactic acid bacteria (LAB) are responsible for different types of food fermentations that provide humans with many different classes of fermented products. During the 20th century, some LAB strains as well as several members of the genus Bifidobacterium started to be extensively used in human nutrition as probiotics because of their health-promoting effects. Nowadays, the subset of extracellular proteins is being investigated as potential mediators of the process known as bacteria-host molecular crosstalk. Inclusion of human cecum extracts in laboratory culture medium modified the production of extracellular proteins by food and probiotic microorganisms. By proteomic and genetic means, the specific overproduction of two proteins was revealed to occur at transcriptional level. This work sheds light on the potential molecular effectors that food bacteria could use for interacting with the human gut and revealed that they may be produced under very specific environmental conditions., (2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.)

To clarify the functional properties of potato pulp (PP), a waste product resulting from extraction of starch from potatoes, we examined the effects of PP on cholesterol metabolism and cecal conditions in rats. Plasma total cholesterol (T-Chol) levels were lower in rats fed a PP-supplemented diet for four weeks than in those fed a control diet. Cecal pH was lowered due to an increase in the levels of cecal total short-chain fatty acids, especially butyrate, in the PP group compared to the control group. Furthermore, animals fed with the PP-supplemented diet showed increased cecal ratios of Lactobacillus and Clostridia and decreased cecal ratios of Bacteroides and Gammaproteobacteria with slightly negative and positive correlations with plasma T-Chol levels, respectively. In conclusion, ingestion of PP for four weeks is likely to improve both cecal conditions and cholesterol metabolism, suggesting that PP has prebiotic effects.

The aim of this study was to investigate whether dietary buckwheat sprouts, cultivated without or with light exposure, exerted different effects on the lower gut, antioxidant status, and lipoprotein profile in rats. For 4 weeks, rats were given a diet containing 30 % expanded buckwheat seeds or 5 % buckwheat sprouts, cultivated with or without light exposure. Buckwheat sprouts that were cultivated under light and dark conditions, and expanded seeds, differed in the levels of total phenolic compounds and Trolox Equivalent Antioxidant Capacity values. All buckwheat products added to the diets decreased pH value and dry matter concentration in the caecal digesta compared with the control group. As compared to the control group, the addition of buckwheat products caused a higher glycolytic activity and the production of short-chain fatty acids in the caecum of the rats. There were no significant differences in the plasma concentrations of glucose, total cholesterol, nor triglycerides between the groups. The concentration of high-density lipoprotein (HDL)-cholesterol was significantly higher, and the atherogenic index of plasma was lower in rats administered buckwheat sprouts cultivated in the light, compared to the group fed sprouts cultivated in the dark. Total plasma antioxidant status, activity of glutathione peroxidase, and superoxide dismutase in whole blood were not affected by dietary treatment. Results of the experiment indicated enhanced benefits of dietary supplementation with buckwheat sprouts cultivated under light, especially in relation to the serum lipoprotein profile.

Our hypothesis in this study was that in vitro disappearance of isoflavones from fecal or cecal contents of Golden Syrian hamsters paralleled the apparent absorption of these compounds, comparable with previous findings from in vitro human fecal incubations. Two studies were conducted to test this idea: one on in vitro fecal (study 1, n = 20/sex) and the other on in vitro cecal contents (study 2, n = 10/sex) ability to degrade isoflavones. According to HPLC analysis, urinary isoflavone excretion was significantly less by 2-4 fold in males compared with females in both studies. Fecal isoflavone excretion was not significantly different between sexes or isoflavones (study 1) and was <0.5% of ingested dose. In vitro anaerobic fecal isoflavone degradation rate constants from study 1 were minimal with no significant correlation between urinary and fecal isoflavone excretion. However, in vitro anaerobic cecal isoflavone degradation rate constants (study 2) were greater and significantly correlated with urinary excretion of daidzein (R = 0.90; p = 0.01) and genistein (R = 0.93; p = 0.004), but not glycitein (R = 0.50; p = 0.3). Both male and female hamsters showed a pattern of urinary isoflavone excretion similar to that found in humans (daidzein > genistein). Hamster in vitro cecal isoflavone degradation rate constants seemed to be analogous to human in vitro fecal isoflavone degradation rate constants for genistein and daidzein. The sex difference in isoflavone excretion in hamsters and the instability in glycitein excretion across studies coupled with the paucity of human data on this isoflavone deserve further investigation.

The bioactivity of lignans depends on their transformation by gut bacteria. The intestinal bacteria Clostridium saccharogumia, Eggerthella lenta, Blautia producta and Lactonifactor longoviformis convert the plant lignan secoisolariciresinol diglucoside via secoisolariciresinol (SECO) into the bioactive enterolignans enterodiol (ED) and enterolactone (EL). While the in vitro conversion of lignans by these bacteria has already been demonstrated, it is unclear whether this defined community is also capable of catalysing lignan transformation in vivo. We therefore associated germ-free rats with these four species. Germ-free rats served as a control. All animals were fed a diet containing 5% ground flaxseed. The caecal contents of rats associated with the four lignan-activating bacteria (ALB rats) contained SECO, ED and EL. The maximal EL formation rate from lignans in the pooled caecal contents of ALB rats was 7.52 nmol min(-1) g(-1) dry matter. The ALB rats excreted EL, but no SECO and ED, in their urine. The caecal contents of germ-free rats contained SECO, but no ED and EL. Their urine was devoid of lignans. Hence, the presence of enterolignans in the ALB rats, but not in the germ-free rats, demonstrates that this defined microbial community is capable of transforming plant lignans into EL in vivo.

Growing evidence suggests that microbiota in the human gastrointestinal tract play a crucial role in mediating the effects of foods on colonic health and host metabolism. The large bowel ecosystem is known to be perturbed in humans and animals fed high-fat diets and conversely to be protected by fermentable oligosaccharides. We examined the ability of largely fermentable dietary fiber from broccoli ( Brassica oleracea L. var. italica ) and minimally fermented microcrystalline cellulose to buffer against the effects of high-fat intakes. The results showed that high fat lowered food intakes and therefore fiber intake by 27%. The addition of fermentable oligosaccharide to the diet was shown to be beneficial to some microbiota in cecum, altered cecal short-chain fatty acids, and increased the colon crypt depth and the number of goblet cells per crypt in high- and low-fat diets. Although, the fat level was the predominant factor in changes to the large bowel ecosystem, we have shown that broccoli fiber conferred some protection to consumption of a high-fat diet and particularly in terms of colon morphology.

This work aimed to study the stability over time of the bacterial community in caecum and faeces of the rabbit (diversity index and structure) without experimental disturbance and to evaluate its relationships with environmental parameters. Soft and hard faeces of 14 rabbits were sampled for 5 weeks while caecal content was sampled on the 3rd week (by surgery) and the 5th week (at slaughter). Bacterial communities were assessed by studying CE-SSCP profiles of 16S rRNA genes fragments. Redox potential, pH, NH3-N concentration and volatile fatty acid concentrations were measured in the caecum. Data showed that bacterial communities of soft and hard faeces barely differed from that of the caecum (ANOSIM-R<0.25; p<0.05). Without disturbance, the bacterial communities of faeces were stable over time (ANOSIM-R<0.25; p<0.001). However, the bacterial communities of caecum and faeces were affected by the surgery (ANOSIM-R=0.22-0.33; p<0.001). The caecal content was an acidic (pH=6.03+/-0.33) and an anaerobic environment (redox potential=-160+/-43 mV). Only the redox potential was correlated with the diversity index of the bacterial community of the caecum (R(2)=0.35; p<0.05) and no environmental parameters were correlated to its structure., (Copyright 2009 Elsevier Ltd. All rights reserved.)

This study examined the effects of cholesterol on mouse intestinal microflora and on isoflavonoids in the cecum and plasma. Dietary cholesterol affects bile acid metabolism and bile acids can influence the intestinal microorganisms. Intestinal microflora appear to play an important role in isoflavone metabolism. We hypothesized that dietary cholesterol changes the metabolism of isoflavonoids and intestinal microorganisms in mice. Male mice were randomly divided into two groups, which were fed a cholesterol-daidzein (CDA) or daidzein (DA) diet (control diet) for 60d. Plasma equol and cecal equol concentrations were significantly higher in the DA group (control group) than in the CDA group. However, plasma cholesterol concentrations were significantly higher in the CDA group compared to the DA group. The composition of cecal microorganisms differed between the two dietary groups. The occupation ratios of Clostridium cluster XI, Clostridium subcluster XIVa, and Lactobacillales were significantly higher in the CDA group. The occupation ratio of Bifidobacterium was significantly lower in the CDA group. This study suggests that dietary cholesterol has the potential to affect the metabolism of equol from daidzein by altering the metabolic activity of the intestinal microorganisms and gut physiological function.

The effects of Lactobacillus collinoides JCM1123(T) on plasma cholesterol levels, isoflavonoids in the caecum and faecal flora were assessed in adult mice. L. collinoides JCM1123(T) altered the equol production status in in vitro incubation of daidzein with faecal flora of mice. In in vivo investigation, mice were fed an AIN-93M purified diet for 13 days, and then randomly divided into two groups of seven animals each. All mice were fed an AIN-93M diet for 6 days; then the diet was replaced with a 0.05% daidzein diet, the mice received a 0.05% daidzein diet for 4 days. Two groups of mice were administered either L. collinoides JCM1123(T) (the experimental group) or a physiological saline solution (the control group) daily for 10 days and dissection was performed on the following day. The total plasma cholesterol concentration was significantly higher in the control group than in the experimental group. The amount of daidzein present in the caecum was significantly higher in the control group than in the experimental group. Significantly higher numbers of lactobacilli were observed in the experimental group than in the control group. Our data suggest that the administration of L. collinoides is likely to influence the metabolism of isoflavonoids and endogenous cholesterol via changes in the gastrointestinal environment.

Aim: To assess the probiotic effects of Lactobacillus agilis JCM 1048 and L. salivarius ssp. salicinius JCM 1230 and the pH on the cecal microflora of chicken and metabolic end products., Methods and Results: An in vitro system, operated with batch bioreactor, was used for this assessment. Selected bacterial species were monitored at two pH values, over 24 h of batch culture incubation. The concentration of short chain fatty acids (SCFA) and lactate in the fermented material was also determined. The addition of L. agilis JCM 1048 and L. salivarius ssp. salicinius JCM 1230 into vessel 2 (Cc + P) increased the total anaerobes, lactobacilli and bifidobacteria after 24 h incubation. Moreover, lactobacilli supplementation decreased the total aerobes and streptococci, but it did not have any effects on coliforms. The supplementation of lactobacilli in vessel 2 (Cc + P) was found to significantly increase the production of lactate, propionate and butyrate. Furthermore, pH did not alter the formation of butyrate, whereas the production of acetate and propionate was significantly decreased at pH = 5.8., Conclusions: L. agilis JCM 1048 and L. salivarius ssp. salicinius JCM 1230, as probiotic bacteria, have the ability to re-establish proper microbial balance by the formation of lactate as well as propionate, and stimulate butyrate-producing bacteria to produce butyrate in the chicken cecum., Significance and Impact of the Study: This study was the first to report this under in vitro conditions, highlighting the probiotic roles of the two Lactobacillus strains in broiler cecal fermentation at different initial pH. These useful data can be helpful in improving the fermentation process in chicken cecum.

Mannitol is a six-carbon sugar alcohol that is widely distributed in plants. Sugar alcohols are widely used in various food products because of their numerous beneficial health effects. The present study investigated the effects of mannitol consumption on digestion, large gut fermentation and nutrient metabolism in normal and cecectomized male Wistar rats. After 28 d of feeding with three kinds of diet containing 0, 4 or 8% mannitol, mannitol consumption dose-dependently lowered the digestibilities of crude fat and crude protein, the ratio of body fat accumulation to energy absorbed and the hepatic and serum triglyceride levels in normal rats. After 24 d of feeding with three kinds of diet comprising a control diet, a 5% mannitol-containing diet and a 5% fructooligosaccharides (FOS)-containing diet, mannitol lowered the digestibility of fat and the ratio of body fat accumulation to energy consumed and absorbed in cecectomized rats. On the other hand, FOS consumption had no effect on the accumulation of body fat, but lowered the digestibility of fat. FOS consumption greatly improved the accumulation of body ash in cecectomized rats. These results suggest that mannitol has a lowering effect on body fat accumulation, and further indicate that the cecum is not essential for the appearance of effects of mannitol on digestion, absorption and metabolism.

Four groups of eight New Zealand hybrid rabbits were fattened with ad libitum access to the following pelleted experimental diets: ryegrass meal or alfalfa meal fed either alone or with oats meal in a ratio of 1:1. After 25 weeks they were slaughtered and dissected. Fatty acid (FA) profiles of caecotrophs (re-ingested fermentation products of the caecum), perirenal adipose tissue and intramuscular fat in the Musculus quadriceps were determined. With high proportions of branched-chain FA (BFA) and trans FA, and increased proportions of saturated FA relative to the diets, the caecotroph FA profile showed a clear fingerprint of anaerobe microbial lipid metabolism including biohydrogenation. By contrast, the FA profiles of adipose and lean tissue comprised high proportions of polyunsaturated FA (PUFA), whilst BFA and trans FA occurred in much lower proportions compared to the caecotrophs. Thus, coprophagy did not substantially modify the FA composition of the tissues investigated. Use of forage-only diets, compared to the oats supplemented diets, led to extraordinary high proportions of n-3 PUFA (including 18:3 and long-chain n-3) in the fat of adipose (21.3 vs. 6.7%) and lean tissue (15.4 vs. 5.7%). The forage type diet (grass vs. alfalfa) had smaller effects on the FA profiles. Indications of diet effects on endogenous desaturation, chain elongation and differential distribution of functional FA between the two tissues investigated were found.

Three different carbohydrate sources (cellulose on wood basis, maize starch and apple pectin) in combination with a low phosphorus (P) basal diet were fed to eight pigs fitted with single ileum-T-cannulas in a balance trial. The effects on net disappearance of dry matter, N, P and Ca as well as phytate (IP6) degradation in the intestine were studied. A basal diet and three diets supplemented with 25% of one carbohydrate source were applied in three experimental periods following an incomplete Latin Square design. Animals were housed individually in balance crates. After 15 days of adaptation to the diets, five days of total excreta collection were followed by two days of spot sampling of ileal digesta. The results showed a significantly decreasing effect of cellulose on the precaecal, postileal and total tract digestibility of DM, N and P. Starch reduced precaecal IP6 degradation and P digestibility. The addition of pectin negatively affected the precaecal digestibility of DM, N and Ca as well as the total tract digestibility of P and Ca. Postileally, cellulose and pectin caused a net secretion while starch induced a net absorption of P.

Background/aims: Feeding rats potato resistant starch improves large bowel health; however, there is little information on the physiological effects of preprocessed starch like potato flakes in animal experiments. The present study was designed to investigate the effects of the consumption of various colored potato (white, red and purple) flakes on cecal fermentation and fecal bile acid excretions in rats., Methods: The control group was fed a basal diet (BD) containing alpha-cornstarch for 4 weeks. The potato flake-treated groups were fed one of the following diets containing a mixture of 299.5 g/kg alpha-cornstarch plus 250 g/kg Hokkai kogane flakes (HK, white), Hokkai No. 91 flakes (H91, red) or Hokkai No. 92 flakes (H92, purple)., Results: There were no significant differences in the body weight, food intake and cecum weight among the groups. Cecal pH values in the HK, H91 and H92 groups were significantly lower than that in the BD group, and matter excretion in the H91 group was significantly higher than in the BD and HK groups. Cecal short-chain fatty acid (SCFA) concentrations in the HK, H91 and H92 groups were significantly higher than in the BD group, and the molar ratio of butyrate to total SCFA in the HK, H91 and H92 groups was greatly increased compared with the BD group. Rats fed the HK, H91 and H92 potato flake diets presented significantly higher counts of total anaerobes in the cecum than rats fed the BD. The cecal Lactobacillus count in the H91 group was significantly increased compared to the BD group and the Bifidobacterium count was similar for all groups. Fecal total bile acid excretion in the H92 flake group and secondary bile acid excretions in the H91 and H92 groups were significantly greater than those in the other groups and in the BD and HK groups, respectively., Conclusion: The results indicate that potato flakes act like resistant starch and raise bowel SCFA, probably through anaerobic bacterial activities and fermentation of residual starch. These actions are helpful for the improvement of the colonic environment., ((c) 2008 S. Karger AG, Basel.)

We tested the cytokinesis-block micronucleus cytome assay using the WIL2-NS human B lymphoblastoid cell line as a biomarker of genotoxicity and cytotoxicity of cecal water from rats and fecal water from humans. Cecal water was assessed in rats fed either a diet rich in fat, low in calcium and fiber, and barbecued red meat as the protein source (high colorectal cancer risk diet) or a diet high in fiber and calcium, low in fat, and casein as the protein source (low colorectal cancer risk diet) for 2 weeks. There was a significant 7.6-, 1.8-, and 4.0-fold increase in binucleated (BN) cells with micronuclei (Mn-BN), BN cells with nucleoplasmic bridges (Npb-BN), and necrotic cells (P < 0.001) with 1-h incubation with a 10% dilution of the cecal water isolated from rats fed the high colorectal cancer risk diet compared with rats fed the low colorectal cancer risk diet. In humans, fecal water samples collected from feces of free-living volunteers showed that 24-h exposure to 1% dilution of fecal water produced a significant 2.6-, 6.5-, 7.5-, and 2.2-fold increase in Mn-BN, Npb-BN, BN cells with nuclear buds, and necrotic cells compared with controls (P < 0.05). The coefficients of variations for interindividual differences for Mn-BN, Npb-BN, BN cells with nuclear buds, and necrosis biomarkers were greater than corresponding coefficients of variations for intraindividual variation. These results indicate that the cytokinesis-block micronucleus cytome assay can be used successfully to determine the interindividual variation in genotoxicity and cytotoxicity of cecal or fecal water and to identify dietary patterns that are likely to increase carcinogenic events in the colon.

To obtain information on the concentration and spectrum of bile acids in human cecal content, samples were obtained from 19 persons who had died an unnatural death from causes such as trauma, homicide, suicide, or drug overdose. Bile acid concentration was measured via an enzymatic assay for 3alpha-hydroxy bile acids; bile acid classes were determined by electrospray ionization mass spectrometry and individual bile acids by gas chromatography mass spectrometry and liquid chromatography mass spectrometry. The 3alpha-hydroxy bile acid concentration (mumol bile acid/ml cecal content) was 0.4 +/- 0.2 mM (mean +/- SD); the total 3-hydroxy bile acid concentration was 0.6 +/- 0.3 mM. The aqueous concentration of bile acids (supernatant after centrifugation) was identical, indicating that most bile acids were in solution. By liquid chromatography mass spectrometry, bile acids were mostly in unconjugated form (90 +/- 9%, mean +/- SD); sulfated, nonamidated bile acids were 7 +/- 5%, and nonsulfated amidated bile acids (glycine or taurine conjugates) were 3 +/- 7%. By gas chromatography mass spectrometry, 10 bile acids were identified: deoxycholic (34 +/- 16%), lithocholic (26 +/- 10%), and ursodeoxycholic (6 +/- 9), as well as their primary bile acid precursors cholic (6 +/- 9%) and chenodeoxycholic acid (7 +/- 8%). In addition, 3beta-hydroxy derivatives of some or all of these bile acids were present and averaged 27 +/- 18% of total bile acids, indicating that 3beta-hydroxy bile acids are normal constituents of cecal content. In the human cecum, deconjugation and dehydroxylation of bile acids are nearly complete, resulting in most bile acids being in unconjugated form at submicellar and subsecretory concentrations.

1. In order to find an alternative source of inoculum to caecal content for studying the in vitro feed digestibility in domesticated ostriches (Struthio camelus var. domesticus), caecal content and faeces of 4 male birds were used as inocula for an in vitro gas production trial. 2. About 1 g of each of 5 substrates (maize silage, CS; alfalfa hay, AH; barley, BG; soybean meal, SM; beet pulp, BP) was weighed, in quadruplicate per inoculum, in 120 ml flasks; 75 ml of anaerobic medium and 4 ml of reducing solution were added and flasks were kept at 39 degrees C. Caecal content and faeces were diluted respectively 1 : 2 (CI) and 1 : 4 (FI) with an anaerobic medium and were injected into the respective flasks (10 ml). 3. Gas production was recorded 22 times up to 120 h of incubation and fermentation characteristics (for instance, degraded organic matter, OMd; potential gas production, A; maximum fermentation rate, Rmax; time at which it is reached, Tmax; pH; volatile fatty acid, VFA; ammonia) were studied for each inoculum and substrate. 4. CI and FI showed significant differences in Tmax (16.37 vs 18.47 h, respectively), propionic (16.47 vs 12.07 mmoles/l) and butyric acid (6.50 vs 7.98 mmoles/l) and ammonia concentration (17.18 vs 19.95 mmoles/l). The substrates, according to their chemical composition, showed different fermentation characteristics. However, the regression equations able to estimate some fermentation characteristics of the caecum from those of faeces were statistically significant and showed R2-values ranging from 0.87 to 0.99. 5. The differences in fermentation pathways of the two inocula did not appear to influence the rate and extent of OM digestion. Faecal fermentation predicted rates and extent of OM digestion by caecal fermentation in ostriches; consequently, the faeces could be considered as an alternative to caecal content to study feed digestibility in the species, although there is a need to undertake further research.

An experiment was conducted to determine the effects of different dietary neutral detergent fibre (NDF) levels on growth performance, nutrient utilization, caecum development, caecal fermentation, slaughter performance, immune organ and fibrolytic activity in 2- to 3-month-old New Zealand meat rabbits. Eighty 2-month-old rabbits were allocated in individual cages for five treatments in which they were fed each diet with NDF at 240, 270, 300, 330 and 360 g/kg respectively. The results are as follows: the average daily gain of 300 g/kg NDF group was the highest (30.09 g/day) and higher than that of 240 g/kg NDF group (p < 0.05). The feed/gain ratio of 300 g/kg NDF group was the lowest (4.27) and lower than those of 240 and 360 g/kg NDF groups (p < 0.05). The coefficient of total tract apparent digestibility (CTTAD) of energy, crude protein, crude fibre and ether extract decreased when dietary NDF increased (p < 0.05); CTTAD of NDF increased when dietary NDF increased (p < 0.01). Digestible nitrogen and retained nitrogen of 240, 270, 300 and 330 g/kg NDF groups were higher than that of 360 g/kg NDF group (p < 0.05). The caecum weight, the proportion of caecum weight to body weight and the acetic acid ratio of volatile fatty acid rose when dietary NDF concentration increased (p < 0.05). The NH(3)-N concentration of caecum dropped when dietary NDF increased (p < 0.05). The fibrolytic activity increased when the dietary NDF increased (p < 0.01).

The effects of different kinds of inulin-type fructans on caecal microbiota were evaluated in rats. Four groups of male Wistar rats were fed either a control diet, or diets containing 5% inulin, 5% fructooligosaccharides (FOS), or 5% difructose anhydride III (DFAIII) for two weeks. In the DFAIII group, caecal propionate, butyrate, counts of bifidobacteria, and total anaerobes were lower than in the inulin group, while caecal propionate, succinate, counts of bifidobacteria, and total anaerobes were lower than in the FOS group. Compared to controls, in the DFAIII group the counts of clostridia in caecum were increased by 3 log units. However, this change was statistically not significant. There were no differences between inulin and FOS groups for the pool of short chain fatty acids in caecum and bacterial counts. Results indicate that DFAIII has different effects on caecal microbiota compared to inulin and FOS and that these differences are most likely due to the alpha(3-->2) bonds in DFAIII.

Objective: We compared the effects of grapefruit flavonoids and inulin, as single dietary components or in a combination, on cecal fermentation in rats adapted to a semipurified diet., Methods: The experimental diets contained 0.3% flavonoid extract and 5% or 10% inulin and a combination of both supplements. The large bowel metabolism assessment was based on cecal parameters: bulk effect, pH, microbial enzymes activity, and short-chain fatty acid production., Results: Both supplements induced significant enlargement of the cecal digesta weight. Acidification of cecal digesta was more pronounced, with a higher inulin addition to the diet. Cecal pH was the highest with the flavonoid-rich diets and lowest in the case of a simultaneous addition of flavonoids and a high content of inulin. The flavonoid extract applied as a single dietary supplement was observed to decrease the activity of bacterial beta-glucosidase and beta- and alpha-galactosidases in the cecal digesta. In contrast, addition of the grapefruit extract to inulin-containing diets increased the activity of alpha-glucosidase, alpha-galactosidase, and beta-galactosidase. Great accumulation of cecal digesta in rats consuming the flavonoid-diet caused a considerable increase in the short-chain fatty acid pool, mainly acetic acid. Inulin added to the diet decreased the excessive enlargement of digesta caused by dietary flavonoids. Dietary addition of inulin to the flavonoid-diet also normalized hydration of cecal digesta and significantly decreased the pH of digesta. The presence of polyphenols in the inulin-containing diets did not change total short-chain fatty acid production in the cecum of rats., Conclusion: Our results suggested that simultaneous intake of inulin and polyphenols can decrease the detrimental effects of the latter on cecal fermentation.