Polydextrose and soluble corn fiber increase five-day fecal wet weight in healthy men and women

Age-Dependent Prebiotic Effects of Soluble Corn Fiber in M-SHIME® Gut Microbial Ecosystems

Soluble corn fiber (SCF) has demonstrated prebiotic effects in clinical studies. Using an in vitro mucosal simulator of the human intestinal microbial ecosystem (M-SHIME^®) model, the effects of SCF treatment on colonic microbiota composition and metabolic activity and on host-microbiome interactions were evaluated using fecal samples from healthy donors of different ages (baby [≤ 2 years], n = 4; adult [18-45 years], n = 2; elderly [70 years], n = 1). During the 3-week treatment period, M-SHIME^® systems were supplemented with SCF daily (baby, 1.5, 3, or 4.5 g/d; adult, 3 or 8.5 g/d; and elderly, 8.5 g/d). M-SHIME^® supernatants were evaluated for their effect on the intestinal epithelial cell barrier and inflammatory responses in lipopolysaccharide. (LPS)-stimulated cells. Additionally, short-chain fatty acid (SCFA) production and microbial community composition were assessed. In the baby and adult models, M-SHIME^® supernatants from SCF treated vessels protected Caco-2 membrane integrity from LPS-induced damage. SCF treatment resulted in the expansion of Bacteroidetes, Firmicutes, and Bifidobacterial, as well as increased SCFA production in all age groups. SCF tended to have the greatest effect on propionate production. These findings demonstrate the prebiotic potential of SCF in babies, adults, and the elderly and provide insight into the mechanisms behind the observed prebiotic effects.

Gastrointestinal Effects and Tolerance of Nondigestible Carbohydrate Consumption

Nondigestible carbohydrates (NDCs) are food components, including nonstarch polysaccharides and resistant starches. Many NDCs are classified as dietary fibers by the US FDA. Because of their beneficial effects on human health and product development, NDCs are widely used in the food supply. Although there are dietary intake recommendations for total dietary fiber, there are no such recommendations for individual NDCs. NDCs are heterogeneous in their chemical composition and physicochemical properties-characteristics that contribute to their tolerable intake levels. Guidance on tolerable intake levels of different NDCs is needed because overconsumption can lead to undesirable gastrointestinal side effects, further widening the gap between actual and suggested fiber intake levels. In this review, we synthesize the literature on gastrointestinal effects of NDCs that the FDA accepts as dietary fibers (β-glucan, pectin, arabinoxylan, guar gum, alginate, psyllium husk, inulin, fructooligosaccharides and oligofructose, galactooligosaccharides, polydextrose, cellulose, soy fiber, resistant maltodextrin/dextrin) and present tolerable intake dose recommendations for their consumption. We summarized the findings from 103 clinical trials in adults without gastrointestinal disease who reported gastrointestinal effects, including tolerance (e.g., bloating, flatulence, borborygmi/rumbling) and function (e.g., transit time, stool frequency, stool consistency). These studies provided doses ranging from 0.75-160 g/d and lasted for durations ranging from a single-meal tolerance test to 28 wk. Tolerance was NDC specific; thus, recommendations ranged from 3.75 g/d for alginate to 25 g/d for soy fiber. Future studies should address gaps in the literature by testing a wider range of NDC doses and consumption forms (solid compared with liquid). Furthermore, future investigations should also adopt a standard protocol to examine tolerance and functional outcomes across studies consistently.

Moderate intakes of soluble corn fibre or inulin do not cause gastrointestinal discomfort and are well tolerated in healthy children

We investigated the gastrointestinal (GI) tolerance of soluble corn fibre (SCF) compared with inulin in children 3-9 years old. SCF (3-8 g/d for 10d) was tolerated as well as inulin: no differences were identified in stool frequency and consistency, proportion of subjects with at least one loose stool or reporting symptoms during bowel movement. Compared to inulin, 6 g/d of SCF lowered gas severity in children aged 3-5 years old. No differences were noted for alpha and beta diversity, relative abundance of Bacteroidota, Firmicutes, Ruminococcaceae, or the Firmicutes to Bacteroidota ratio. Relative abundance of some specific strains (i.e. Anaerostipes, Bifidobacterium, Fusicatenibacter, Parabacteroides) varied depending on the fibre type and dose level. Fortification at a level of 6-8 g/d of SCF and/or inulin could help addressing the fibre gap without any GI discomfort.

Technician-Scored Stool Consistency Spans the Full Range of the Bristol Scale in a Healthy US Population and Differs by Diet and Chronic Stress Load

BACKGROUND

Prior studies of adults with constipation or diarrhea suggest that dietary intake, physical activity, and stress may affect stool consistency. However, the influence of these factors is unresolved and has not been investigated in healthy adults.

OBJECTIVES

We assessed the relations of technician-scored stool consistency in healthy adults with self-reported diet, objectively monitored physical activity, and quantifiable markers of stress.

METHODS

Stool consistency was scored by an independent technician using the Bristol Stool Form Scale (BSFS) to analyze samples provided by healthy adults, aged 18-65 y, BMI 18-44 kg/m2, in the USDA Nutritional Phenotyping Study (n = 364). A subset of participants (n = 109) were also asked to rate their sample using the BSFS. Dietary intake was assessed with two to three 24-h recalls completed at home and energy expenditure from physical activity was monitored using an accelerometer in the 7-d period preceding the stool collection. Stress was measured using the Wheaton Chronic Stress Inventory and allostatic load (AL). Statistical and machine learning analyses were conducted to determine which dietary, physiological, lifestyle, and stress factors differed by stool form.

RESULTS

Technician-scored BSFS scores were significantly further (P = 0.003) from the central score (mean ± SEM distance: 1.41 ± 0.089) than the self-reported score (1.06 ± 0.086). Hard stool was associated with higher (P = 0.005) intake of saturated fat (13.8 ± 0.40 g/1000 kcal) than was normal stool (12.5 ± 0.30 g/1000 kcal). AL scores were lower for normal stool (2.49 ± 0.15) than for hard (3.07 ± 0.18) (P = 0.009) or soft stool (2.89 ± 0.18) (P = 0.049). Machine learning analyses revealed that various dietary components, physiological characteristics, and stress hormones predicted stool consistency.

CONCLUSIONS

Technician-scored stool consistency differed by dietary intake and stress hormones, but not by physical activity, in healthy adults.This trial was registered at clincialtrials.gov as NCT02367287.

Possible transmission of viruses from contaminated human feces and sewage: Implications for SARS-CoV-2

Humanity has experienced outbreaks by viruses such as severe acute respiratory syndrome coronavirus 1 (SARS-CoV-1) in 2003, Eastern respiratory syndrome coronavirus (MERS-CoV) in 2012, Ebola virus in 2014 and nowadays SARS-CoV-2. While clinicians seek for a vaccine to reduce the epidemic outbreak, environmental engineers need to understand consequence of virus entity in sewage given the reported persistency of viruses in human feces and sewage environments for more than days. Herein, we discuss about concerns associated with virus occurrence in human feces and sewage, with attention to the possible SARS-CoV-2 transmission routes, based on the review of recent studies on SARS-CoV-2 as well as the previous pandemic events. Given the reported environmental stability of coronavirus, the feces- and sewage-derived transmission routes may be of importance to prevent unprecedented spread of coronavirus disease 2019 (COVID-19) particularly in developing countries. However, so far, limited number of studies detected infectious SARS-CoV-2 even in human feces, whereas a number of virus RNA copies were identified in both feces and sewage specimens. Therefore, uncertainty remains in the possibility of this transmission pathway, and further investigation is warranted in future studies, for example, by increasing the number of specimens, examining the effectiveness of methods for viral viability test, considering the patient medical history, and so forth.

Efficacy of Polydextrose Supplementation on Colonic Transit Time, Bowel Movements, and Gastrointestinal Symptoms in Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

The addition of fiber is one of the most important dietary means to relieve constipation through lifestyle modification. Polydextrose (PDX) has been reported in several studies to increase fecal bulk, soften stools, and increase the number of defecations. However, there are few studies on the effect of PDX on colonic transit time (CTT). Therefore, the aim of this study was to demonstrate the effect of PDX on CTT and other aspects of gastrointestinal function during two weeks (Day 1 to Day 14), preceded by a 2-week run-in period (Day -14 to Day -1). A total of 192 adults who were diagnosed with functional constipation per Rome III criteria were recruited for the study. Participants were randomized equally into 4 groups (12 g, 8 g, or 4 g of PDX or placebo per day). The primary endpoint was CTT, assessed using radio-opaque markers and abdominal X-rays on Day 0, the baseline; and Day 15, the end of the intervention. Secondary outcomes that were measured using inventories were the patient assessment of constipation symptoms and quality of life, bowel function index, relief of constipation, bowel movement frequency (BMF), stool consistency, degree of straining, and proportion of bowel movements. Ancillary parameters and harms were also evaluated. The recruited population was not sufficiently constipated (e.g., baseline values for CTT and BMF of 42 h and 8.7 BMF/week, respectively). Despite this limitation, our results demonstrated an increased number of bowel movements when supplemented with PDX at a dosage of 12 g per day for 2 weeks. This dosage also consistently improved the secondary outcomes that were measured using inventories at Day 15, compared with the baseline. No serious or significant adverse events were reported during the study.

The Role of Fiber in the Treatment of Functional Gastrointestinal Disorders in Children

We reviewed the available evidence on the role of fiber in the treatment of Functional Constipation (FC) and Irritable Bowel Syndrome (IBS) in children. The vast majority of toddlers and preschoolers do not consume enough fiber. Two of the most common reasons for consultation to a pediatric gastroenterology practice include FC and IBS. The North American Society for Pediatric Gastroenterology, Hepatology, and Nutrition (NASPGHAN) and the European Society of Pediatric Gastroenterology, Hepatology, and Nutrition (ESPGHAN) guidelines state that the evidence does not support the use of fiber supplements in the treatment of FC in children, and the Rome IV criteria do not recommend an increase in fiber consumption, in children with IBS. Despite this, in general practice, it is commonly recommended that children who experience constipation and IBS to increase their fiber intake. We conducted a systematic review of the available evidence on the role of fiber in the treatment of FC and IBS in children. Thirteen full-text articles with a total of seven hundred and twenty-three pediatric participants were included in this review. Three clinical trials found positive effects of dietary fiber for the management of IBS. Nine out of ten trials found fiber to be either more effective than placebo, or just as effective as laxative treatment. Most studies on the use of fiber for the treatment of FC and IBS have shown its benefit. However, due to the heterogeneity in study design, length of treatment, outcome measures, and amount and type of fiber, we were unable to make a definitive recommendation supporting the use of fiber for the treatment of FC and IBS in children.

Impact of Agaricus bisporus Mushroom Consumption on Gut Health Markers in Healthy Adults

Eating Agaricus bisporus mushrooms may impact gut health, because they contain known prebiotics. This study assessed mushroom consumption compared to meat on gastrointestinal tolerance, short chain fatty acid (SCFA) production, laxation, and fecal microbiota. A randomized open-label crossover study was conducted in healthy adults (n = 32) consuming protein-matched amounts of mushrooms or meat twice daily for ten days. Breath hydrogen measures were taken on day one, and gastrointestinal tolerance was evaluated throughout treatments. Fecal sample collection was completed days 6⁻10, and samples were assessed for bacterial composition, SCFA concentrations, weight, pH, and consistency. There were no differences in breath hydrogen, stool frequency, consistency, fecal pH, or SCFA concentrations between the two diets. The mushroom diet led to greater overall gastrointestinal symptoms than the meat diet on days one and two. The mushroom-rich diet resulted in higher average stool weight (p = 0.002) and a different fecal microbiota composition compared to the meat diet, with greater abundance of Bacteroidetes (p = 0.0002) and lower abundance of Firmicutes (p = 0.0009). The increase in stool weight and presence of undigested mushrooms in stool suggests that mushroom consumption may impact laxation in healthy adults. Additional research is needed to interpret the health implications of fecal microbiota shifts with mushroom feeding.

Short-Term Daily Intake of Polydextrose Fiber Does Not Shorten Intestinal Transit Time in Constipated Adults: A Randomized Controlled Trial

Chronic constipation (CC) remains a common gastrointestinal (GI) disorder that conveys a substantial healthcare burden. Expert guidelines recommend increasing fiber intake, yet the clinical evidence to support this needs strengthening for specific fibers. The aim was to evaluate changes in intestinal transit time and GI symptoms in CC patients who consumed polydextrose. In a randomized, double-blind, placebo-controlled trial, 128 adults with CC received 8 g or 12 g polydextrose, or placebo, daily for 4 weeks. Transit time, as primary outcome, was assessed by radiopaque marker distribution after 2-weeks intervention. Bowel habits, GI symptoms and quality of life (QOL) were assessed by questionnaire, including the Patient-Assessment of Constipation (PAC) Symptoms (SYM), and PAC-QOL. Following 2-weeks intervention, no reduction was seen in transit time in any group and following 2- or 4-weeks intervention, no improvements were seen in stool frequency or consistency in any group. After 2-weeks intervention with 8 g/day polydextrose an improvement was seen in the PAC-SYM rectal score (p = 0.041). After 4-weeks intervention both rectal (p = 0.049) and stool (p = 0.029) scores improved while improvement in the QOL satisfaction score did not reach significance (p = 0.071). Overall, the results suggest that 2-weeks consumption of 8 or 12 g/day polydextrose does not significantly improve physiological measures of gut function in CC adults. Longer term consumption may improve clinical measures, but further studies will be required to substantiate this.

The effects of soluble corn fibre and isomaltooligosacharides on blood glucose, insulin, digestion and fermentation in healthy young males and females

Dietary fibre refers to nutrients in the diet that gastrointestinal enzymes do not digest. If properly labelled, dietary fibres should not significantly elevate blood glucose or insulin and should ferment in the large intestine. Because of the recent rise in low-carbohydrate products on the market, consumers use these various fibres without adequate knowledge concerning whether or not these ingredients affect any blood parameters and constitute a dietary fibre. The aim of this study was to examine the impact of isomaltooligosaccharides (IMO) as compared to soluble corn fibre (SCF) consumption on blood glucose, insulin and breath hydrogen responses in healthy young men and women. After an overnight fast, nine individuals consumed 25 g of either placebo (PLA), IMO or SCF. Breath hydrogen was significantly higher in the SCF condition than in the IMO and PLA at 90, 120, 150 and 180 min (p < 0.0001). Blood glucose and insulin were higher in the IMO condition (p < 0.0001) at 30 min compared to the SCF or PLA conditions, which were not significantly different from each other. These data suggest that IMO does not constitute a dietary fibre and instead should be explored as a slow-digesting carbohydrate.

Digestion-resistant maltodextrin effects on colonic transit time and stool weight: a randomized controlled clinical study

PURPOSE

Increased awareness of the importance of dietary fibre has led to increased interest in "functional" fibre components like digestion-resistant maltodextrin (RMD). This randomized, placebo-controlled, double-blind study assessed the effects of RMD in the colonic transit time (CTT) and defecation characteristics (frequency, stool volume and consistency).

METHODS

Sixty-six healthy adult volunteers (32 men) who did not have a daily defecation habit had a 7-day run-in period before the 21-day intervention period with RMD or placebo. CTT and segmental CTT (SCTT) were assessed by a single abdominal X-ray film taken at the end of both periods after radiopaque marker ingestion. Defecation characteristics and intestinal functions were also assessed, which were self-reported by patients. Intragroup comparisons were evaluated by Student's paired t test, Bonferroni test and Chi-square test, while time comparisons by analysis of variance (ANOVA) and time-by-treatment interaction by repeated-measures ANOVA.

RESULTS

Fifty-seven subjects were assessed for CTT (placebo, n = 28; RMD, n = 29). In the RMD group, the total CTT, left SCTT and rectosigmoidal SCTT decreased significantly compared to baseline (p < 0.01 each; -13.3, -4.7, -8.7 h, respectively). Significant differences between groups were observed in total CTT and left SCTT. Significant time-by-treatment interaction was observed in the RMD group for stool volume (p = 0.014), increasing 56 % compared to baseline (p < 0.01), while remained unchanged in the placebo group. Stool consistency was improved only in the RMD group (p < 0.01). No adverse effects related to study products were observed.

CONCLUSIONS

The results show that RMD improved CTT, stool volume, stool consistency and some intestinal functions in a healthy population.

Fermented Fiber Supplements Are No Better Than Placebo for a Laxative Effect

BACKGROUND

Misconceptions about the effects of dietary fiber and 'functional' fiber on stool parameters and constipation persist in the literature.

METHODS

A comprehensive literature review was conducted with the use of the Scopus and PubMed scientific databases to identify and objectively assess well-controlled clinical studies that evaluated the effects of fiber on stool parameters and constipation.

RESULTS

The totality of well-controlled randomized clinical studies show that, to exert a laxative effect, fiber must: (1) resist fermentation to remain intact throughout the large bowel and present in stool, and (2) significantly increase stool water content and stool output, resulting in soft/bulky/easy-to-pass stools. Poorly fermented insoluble fiber (e.g., wheat bran) remains as discreet particles which can mechanically irritate the gut mucosa, stimulating water & mucous secretion if the particles are sufficiently large/coarse. For soluble fibers, some have no effect on viscosity (e.g., inulin, wheat dextrin) while others form high viscosity gels (e.g., β-glucan, psyllium). If the soluble fiber is readily fermented, whether non-viscous or gel-forming, it has no effect on stool output or stool water content, and has no laxative effect. In contrast, a non-fermented, gel-forming soluble fiber (e.g., psyllium) retains its gelled nature and high water-holding capacity throughout the large bowel, resulting in soft/bulky/easy-to-pass stools.

CONCLUSION

When considering a recommendation for a fiber supplement regimen to treat and/or prevent constipation, it is important to consider which fibers have the physical characteristics to exert a laxative effect, and which fiber supplements have rigorous clinical evidence of a significant benefit in patients with constipation.

Positive effects of resistant starch supplementation on bowel function in healthy adults: a systematic review and meta-analysis of randomized controlled trials

Animal experimental studies have found that resistant starch can significantly improve bowel function, but the outcomes are mixed while conducting human studies. Thus, we conducted a systematic review and meta-analysis of randomized controlled trials to evaluate the relationship between resistant starch supplementation and large intestinal function. Three electronic databases (PubMed, Embase, Scopus) were searched to identify eligible studies. The standardized mean difference (SMD) or weighted mean difference (WMD) was calculated using a fixed-effects model or a random-effects model. The pooled findings revealed that resistant starch significantly increased fecal wet weight (WMD 35.51 g/d, 95% CI 1.21, 69.82) and butyrate concentration (SMD 0.61, 95% CI 0.32, 0.89). Also, it significantly reduced fecal PH (WMD -0.19, 95% CI -0.35, -0.03), but the increment of defecation frequency were not statistically significant (WMD 0.04stools/g, 95% CI -0.08, 0.16). To conclude, our study found that resistant starch elicited a beneficial effect on the function of large bowel in healthy adults.[Formula: see text].

Prebiotic Potential of a Maize-Based Soluble Fibre and Impact of Dose on the Human Gut Microbiota

Dietary management of the human gut microbiota towards a more beneficial composition is one approach that may improve host health. To date, a large number of human intervention studies have demonstrated that dietary consumption of certain food products can result in significant changes in the composition of the gut microbiota i.e. the prebiotic concept. Thus the prebiotic effect is now established as a dietary approach to increase beneficial gut bacteria and it has been associated with modulation of health biomarkers and modulation of the immune system. Promitor™ Soluble Corn Fibre (SCF) is a well-known maize-derived source of dietary fibre with potential selective fermentation properties. Our aim was to determine the optimum prebiotic dose of tolerance, desired changes to microbiota and fermentation of SCF in healthy adult subjects. A double-blind, randomised, parallel study was completed where volunteers (n = 8/treatment group) consumed 8, 14 or 21 g from SCF (6, 12 and 18 g/fibre delivered respectively) over 14-d. Over the range of doses studied, SCF was well tolerated Numbers of bifidobacteria were significantly higher for the 6 g/fibre/day compared to 12 g and 18 g/fibre delivered/day (mean 9.25 and 9.73 Log10 cells/g fresh faeces in the pre-treatment and treatment periods respectively). Such a numerical change of 0.5 Log10 bifidobacteria/g fresh faeces is consistent with those changes observed for inulin-type fructans, which are recognised prebiotics. A possible prebiotic effect of SCF was therefore demonstrated by its stimulation of bifidobacteria numbers in the overall gut microbiota during a short-term intervention.

Effect of 4'galactooligosaccharide on constipation symptoms

OBJECTIVE

Fructooligosacharides and galactooligosacharides soften fecal bolus and increase frequency of depositions when added to infant formula. This study aimed to determine the effects of galactooligosaccharide in pediatric patients with chronic constipation.

METHODS

From 2010 to 2012, 20 constipated patients (4-16 years of age) attended to at a primary healthcare unit were enrolled in a double-blinded, placebo-controlled crossover trial. Eleven children ingested galactooligosaccharide (1.7 g) for 30 days, followed by a 15-day washout period, and a 30-day period of placebo (maltodextrin). Nine patients ingested maltodextrin for 30 days, followed by 15-day washout period, and galactooligosaccharide (1.7 g) for 30 days. Constipation symptoms were considered as primary outcomes: bowel movements/week, straining during defecation, and stool consistency. Outcome symptoms were ranked according to a numerical scale elaborated for this study. Data were recorded at baseline, and on days 15 and 30 of each 30-day crossover period. Repeated-measures analysis of variance (ANOVA) was used to analyze symptoms along time.

RESULTS

At baseline, there was no significant difference in symptoms severity between groups (p=0.45). Galactooligosaccharide ingestion was related to increase of the bowel movement frequency, p<0.0001; relief of defecation straining, p<0.0001; and decrease in stool consistency, p=0.0014, compared to placebo ingestion. Patients reported no side effects from galactooligosaccharide.

CONCLUSION

Galactooligosaccharide was effective at improving clinical symptoms in this group of constipated children.

The role of polydextrose in body weight control and glucose regulation

PURPOSE OF REVIEW

The purpose of this review was to highlight recent research developments on effects of the dietary fibre polydextrose (PDX) on appetite, satiety and energy intake and glucose metabolism. For this purpose, clinically relevant human studies were reviewed and putative mechanisms and pathways were discussed.

RECENT FINDINGS

A number of acute human intervention studies provide strong indications for an energy and glucose metabolism-regulating role of PDX. These effects might be mediated via a reduced gastro-intestinal transit reducing glycaemia and insulinemia after PDX ingestion and the potential of PDX as soluble dietary fibre to alter the intestinal microbial composition, which might lead to changes in signalling in both peripheral and central pathways involved in energy metabolism and glucose homeostasis.

SUMMARY

In acute studies, PDX seems to have an inhibiting effect on energy intake and satiety and to reduce glycaemic and insulinemic response through effect on gastro-intestinal transit time and macronutrient absorption as well as through effects of the microbial products such as short-chain fatty acids on energy and substrate metabolism. In particular, well controlled human intervention studies are required to confirm these effects in the long term. Overall, supplement PDX to the daily diet may be a promising approach for the management and treatment of obesity and associated metabolic disorders.

The fermentation of polydextrose in the large intestine and its beneficial effects

Polydextrose is a randomly bonded glucose polymer with a highly branched and complex structure. It resists digestion in the upper gastrointestinal tract and is partially fermented in the large intestine by the colonic microbes. Due to its complex structure, a plethora of microbes is required for the catabolism of polydextrose and this process occurs slowly. This gradual fermentation of polydextrose gives rise to moderate amounts of fermentation products, such as short chain fatty acids and gas. The production of these metabolites continues in the distal part of the colon, which is usually considered to be depleted of saccharolytic fermentation substrates. The fermentation of polydextrose modifies the composition of the microbiota in the colon, and has been shown to impact appetite and satiety in humans and improve the gastrointestinal function. The purpose of this short review is to summarise the in vitro, in vivo and human studies investigating the fermentation properties of polydextrose in the large intestine.

Health benefits of prebiotic fibers

This chapter describes the various compounds that can act as prebiotic fibers: their structure, occurrence, production, and physiological effects (health effects) will be presented. The basis for the description is the latest definitions for dietary fibers and for prebiotics. Using as much as possible data from human studies, both the fiber and the prebiotic properties will be described of a variety of compounds. Based on the presented data the latest developments in the area of prebiotics, fibers and gut and immune health will be discussed in more detail as they show best what the potential impact of prebiotics on health of the human host might be.

Wheat bran extract alters colonic fermentation and microbial composition, but does not affect faecal water toxicity: a randomised controlled trial in healthy subjects

Wheat bran extract (WBE), containing arabinoxylan-oligosaccharides that are potential prebiotic substrates, has been shown to modify bacterial colonic fermentation in human subjects and to beneficially affect the development of colorectal cancer (CRC) in rats. However, it is unclear whether these changes in fermentation are able to reduce the risk of developing CRC in humans. The aim of the present study was to evaluate the effects of WBE on the markers of CRC risk in healthy volunteers, and to correlate these effects with colonic fermentation. A total of twenty healthy subjects were enrolled in a double-blind, cross-over, randomised, controlled trial in which the subjects ingested WBE (10 g/d) or placebo (maltodextrin, 10 g/d) for 3 weeks, separated by a 3-week washout period. At the end of each study period, colonic handling of NH3 was evaluated using the biomarker lactose[15N, 15N']ureide, colonic fermentation was characterised through a metabolomics approach, and the predominant microbial composition was analysed using denaturing gradient gel electrophoresis. As markers of CRC risk, faecal water genotoxicity was determined using the comet assay and faecal water cytotoxicity using a colorimetric cell viability assay. Intake of WBE induced a shift from urinary to faecal 15N excretion, indicating a stimulation of colonic bacterial activity and/or growth. Microbial analysis revealed a selective stimulation of Bifidobacterium adolescentis. In addition, WBE altered the colonic fermentation pattern and significantly reduced colonic protein fermentation compared with the run-in period. However, faecal water cytotoxicity and genotoxicity were not affected. Although intake of WBE clearly affected colonic fermentation and changed the composition of the microbiota, these changes were not associated with the changes in the markers of CRC risk.

Detection of pathogenic viruses in sewage provided early warnings of hepatitis A virus and norovirus outbreaks

Most persons infected with enterically transmitted viruses shed large amounts of virus in feces for days or weeks, both before and after onset of symptoms. Therefore, viruses causing gastroenteritis may be detected in wastewater, even if only a few persons are infected. In this study, the presence of eight pathogenic viruses (norovirus, astrovirus, rotavirus, adenovirus, Aichi virus, parechovirus, hepatitis A virus [HAV], and hepatitis E virus) was investigated in sewage to explore whether their identification could be used as an early warning of outbreaks. Samples of the untreated sewage were collected in proportion to flow at Ryaverket, Gothenburg, Sweden. Daily samples collected during every second week between January and May 2013 were pooled and analyzed for detection of viruses by concentration through adsorption to milk proteins and PCR. The largest amount of noroviruses was detected in sewage 2 to 3 weeks before most patients were diagnosed with this infection in Gothenburg. The other viruses were detected at lower levels. HAV was detected between weeks 5 and 13, and partial sequencing of the structural VP1protein identified three different strains. Two strains were involved in an ongoing outbreak in Scandinavia and were also identified in samples from patients with acute hepatitis A in Gothenburg during spring of 2013. The third strain was unique and was not detected in any patient sample. The method used may thus be a tool to detect incipient outbreaks of these viruses and provide early warning before the causative pathogens have been recognized in health care.

Comparison of faecal microbial community of lantang, bama, erhualian, meishan, xiaomeishan, duroc, landrace, and yorkshire sows

The objective of this study was to investigate differences in the faecal microbial composition among Lantang, Bama, Erhualian, Meishan, Xiaomeishan, Duroc, Landrace, and Yorkshire sows and to explore the possible link of the pig breed with the gut microbial community. Among the sows, the Meishan, Landrace, Duroc, and Yorkshire sows were from the same breeding farm with the same feed. Fresh faeces were collected from three sows of each purebred breed for microbiota analysis and volatile fatty acid (VFA) determination. Denaturing gradient gel electrophoresis (DGGE) analysis revealed that samples from Bama, Erhualian, and Xiaomeishan sows, which from different farms, were generally grouped in one cluster, with similarity higher than 67.2%, and those from Duroc, Landrace, and Yorkshire sows were grouped in another cluster. Principal component analysis of the DGGE profile showed that samples from the foreign breeds and the samples from the Chinese indigenous breeds were scattered in two different groups, irrespective of the farm origin. Faecal VFA concentrations were significantly affected by the pig breed. The proportion of acetate was higher in the Bama sows than in the other breeds. The real-time PCR analysis showed that 16S rRNA gene copies of total bacteria, Firmicutes and Bacteroidetes were significantly higher in the Bama sows compared to Xiaomeishan and Duroc sows. Both Meishan and Erhualian sows had higher numbers of total bacteria, Firmicutes, Bacteroidetes and sulphate-reducing bacteria as compared to Duroc sows. The results suggest that the pig breed affects the composition of gut microbiota. The microbial composition is different with different breeds, especially between overseas breeds (lean type) and Chinese breeds (relatively obese type).

Effect of novel fiber ingredients on ileal and total tract digestibility of energy and nutrients in semi-purified diets fed to growing pigs

BACKGROUND

Consumption of different dietary fibers may influence the digestibility of carbohydrates and other nutrients. Therefore the objectives of this experiment were to determine the effect of novel fiber ingredients on the apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of gross energy (GE), dry matter (DM), crude protein (CP) and total dietary fiber (TDF) in pigs and to calculate the standardized digestibility of analyzed TDF in four novel fiber ingredients.

RESULTS

The AID of DM and GE in diets containing novel fiber ingredients was less (P < 0.05) than in a maltodextrin diet. Addition of cellulose or pullulan, but not resistant starch (RS) 60, RS 75 or soluble corn fiber 70, reduced (P < 0.05) the AID of CP. The average ileal and total tract endogenous losses of analyzed TDF were calculated at 25.25 and 42.87 g kg⁻¹ DM intake, respectively.

CONCLUSION

Addition of novel fiber ingredients to a maltodextrin-based diet had different effects on the AID of DM, CP, GE and TDF. Measurements of the standardized digestibility of analyzed TDF may be a better indicator of TDF fermentability than measurements of AID and ATTD of TDF, because some endogenous metabolites may be analyzed as TDF.