Effect of Dietary Inulin Supplementation on the Gut Microbiota Composition and Derived Metabolites of Individuals Undergoing Hemodialysis: A Pilot Study.

OBJECTIVE: The prebiotic fiber inulin has been studied in individuals undergoing hemodialysis (HD) due to its ability to reduce gut microbiota-derived uremic toxins. However, studies examining the effects of inulin on the gut microbiota and derived metabolites are limited in these patients. We aimed to assess the impact of a 4-week supplementation of inulin on the gut microbiota composition and microbial metabolites of patients on HD. DESIGN AND METHODS: In a randomized, double-blind, placebo-controlled, crossover study, twelve HD patients (55 ± 10 y, 50% male, 58% Black American, BMI 31.6 ± 8.9 kg/m2, 33% diabetes mellitus) were randomized to consume inulin [10 g/d for females; 15 g/d for males] or maltodextrin [6 g/d for females; 9 g/d for males] for 4 weeks, with a 4-week washout period. We assessed the fecal microbiota composition, fecal metabolites (short-chain fatty acids (SCFA), phenols, and indoles), and plasma indoxyl sulfate and p-cresyl sulfate. RESULTS: At baseline, factors that explained the gut microbiota variability included BMI category and type of phosphate binder prescribed. Inulin increased the relative abundance of the phylum Verrucomicrobia and its genus Akkermansia (P interaction = 0.045). Inulin and maltodextrin resulted in an increased relative abundance of the phylum Bacteroidetes and its genus Bacteroides (P time = 0.04 and 0.03, respectively). Both treatments increased the fecal acetate and propionate (P time = 0.032 and 0.027, respectively), and there was a trend toward increased fecal butyrate (P time = 0.06). Inulin did not reduce fecal p-cresol or indoles, or plasma concentrations of p-cresyl sulfate or indoxyl sulfate. CONCLUSIONS: A 4-week supplementation of inulin did not lead to major shifts in the fecal microbiota and gut microbiota-derived metabolites. This may be due to high variability among participants and an unexpected increase in fecal excretion of SCFA with maltodextrin. Larger studies are needed to determine the effects of prebiotic fibers on the gut microbiota and clinical outcomes to justify their use in patients on HD.

Considerations for best practices in studies of fiber or other dietary components and the intestinal microbiome.

A 2-day workshop organized by the National Institutes of Health and U.S. Department of Agriculture included 16 presentations focused on the role of diet in alterations of the gastrointestinal microbiome, primarily that of the colon. Although thousands of research projects have been funded by U.S. federal agencies to study the intestinal microbiome of humans and a variety of animal models, only a minority addresses dietary effects, and a small subset is described in sufficient detail to allow reproduction of a study. Whereas there are standards being developed for many aspects of microbiome studies, such as sample collection, nucleic acid extraction, data handling, etc., none has been proposed for the dietary component; thus this workshop focused on the latter specific point. It is important to foster rigor in design and reproducibility of published studies to maintain high quality and enable designs that can be compared in systematic reviews. Speakers addressed the influence of the structure of the fermentable carbohydrate on the microbiota and the variables to consider in design of studies using animals, in vitro models, and human subjects. For all types of studies, strengths and weaknesses of various designs were highlighted, and for human studies, comparisons between controlled feeding and observational designs were discussed. Because of the lack of published, best-diet formulations for specific research questions, the main recommendation is to describe dietary ingredients and treatments in as much detail as possible to allow reproduction by other scientists.

Agave Inulin Supplementation Affects the Fecal Microbiota of Healthy Adults Participating in a Randomized, Double-Blind, Placebo-Controlled, Crossover Trial.

BACKGROUND: Prebiotics resist digestion, providing fermentable substrates for select gastrointestinal bacteria associated with health and well-being. Agave inulin differs from other inulin type fibers in chemical structure and botanical origin. Preclinical animal research suggests these differences affect bacterial utilization and physiologic outcomes. Thus, research is needed to determine whether these effects translate to healthy adults. OBJECTIVE: We evaluated agave inulin utilization by the gastrointestinal microbiota by measuring fecal fermentative end products and bacterial taxa. METHODS: A randomized, double-blind, placebo-controlled, 3-period, crossover trial was undertaken in healthy adults (n = 29). Participants consumed 0, 5.0, or 7.5 g agave inulin/d for 21 d with 7-d washouts between periods. Participants recorded daily dietary intake; fecal samples were collected during days 16-20 of each period and were subjected to fermentative end product analysis and 16S Illumina sequencing. RESULTS: Fecal Actinobacteria and Bifidobacterium were enriched (P < 0.001) 3- and 4-fold after 5.0 and 7.5 g agave inulin/d, respectively, compared with control. Desulfovibrio were depleted 40% with agave inulin compared with control. Agave inulin tended (P < 0.07) to reduce fecal 4-methyphenol and pH. Bivariate correlations revealed a positive association between intakes of agave inulin (g/kcal) and Bifidobacterium (r = 0.41, P < 0.001). Total dietary fiber intake (total fiber plus 0, 5.0, or 7.5 g agave inulin/d) per kilocalorie was positively associated with fecal butyrate (r = 0.30, P = 0.005), tended to be positively associated with Bifidobacterium (r = 0.19, P = 0.08), and was negatively correlated with Desulfovibrio abundance (r = -0.31, P = 0.004). CONCLUSIONS: Agave inulin supplementation shifted the gastrointestinal microbiota composition and activity in healthy adults. Further investigation is warranted to determine whether the observed changes translate into health benefits in human populations. This trial was registered at clinicaltrials.gov as NCT01925560.

Modulation of the faecal microbiome of healthy adult dogs by inclusion of potato fibre in the diet.

Inclusion of fermentable fibres in the diet can have an impact on the hindgut microbiome and provide numerous health benefits to the host. Potato fibre (PF), a co-product of potato starch isolation, has a favourable chemical composition of pectins, resistant and digestible starch, cellulose, and hemicelluloses. The objective of the present study was to evaluate the effect of increasing dietary PF concentrations on the faecal microbiome of healthy adult dogs. Fresh faecal samples were collected from ten female dogs with hound bloodlines (6·13 (SEM 0·17) years; 22·0 (SEM 2·1) kg) fed five test diets containing graded concentrations of PF (0, 1·5, 3, 4·5 or 6% as-fed; Roquette Frères) in a replicated 5 × 5 Latin square design. Extraction of DNA was followed by amplification of the V4-V6 variable region of the 16S rRNA gene using barcoded primers. Sequences were classified into taxonomic levels using Basic Local Alignment Search Tool (BLASTn) against a curated GreenGenes database. Inclusion of PF increased (P< 0·05) the faecal proportions of Firmicutes, while those of Fusobacteria decreased (P< 0·05). Similar shifts were observed at the genus level and were confirmed by quantitative PCR (qPCR) analysis. With increasing concentrations of PF, faecal proportions of Faecalibacterium increased (P< 0·05). Post hoc Pearson's correlation analysis showed positive (P< 0·05) correlations with Bifidobacterium spp. and butyrate production and Lactobacillus spp. concentrations. Overall, increases in the proportion of Faecalibacterium (not Lactobacillus/Bifidobacterium, as confirmed by qPCR analysis) and faecal SCFA concentrations with increasing dietary PF concentrations suggest that PF is a possible prebiotic fibre.

Fecal metabolomics of healthy breast-fed versus formula-fed infants before and during in vitro batch culture fermentation.

Nontargeted metabolomics analyses were used (1) to compare fecal metabolite profiles of healthy breast-fed (BF) and formula-fed (FF) infants before and during in vitro fermentation in batch culture and (2) to evaluate fecal metabolomics in assessing infant diet. Samples from healthy BF (n = 4) or FF (n = 4) infants were individually incubated at 37( °)C in anaerobic media containing 1% (wt/vol) galactooligosaccharides, 6'-sialyllactose, 2'-fucosyllactose, lacto-N-neotetraose, inulin, and gum arabic for up to 6 h, and supernatants were analyzed using GC/MS and LC/MS/MS to assess changes in various compounds. Comparison of over 250 metabolites prior to incubation showed that BF samples contained higher relative concentrations (P ≤ 0.05) of 14 compounds including human milk oligosaccharides and other metabolites presumably transferred through breast feeding (linoelaidate, myo-inositol) (P ≤ 0.05). Conversely, feces from FF infants contained 41 identified metabolites at higher levels (P ≤ 0.05) with many indicative of carbon limitation and protein fermentation. Our data are consistent with the notion that carbon-limited cultures catabolize protein and amino acids to obtain energy, whereas the provision of fermentable carbohydrate creates anabolic conditions relying on amino acids for bacterial growth. Results also suggest that fecal metabolomics can be a useful tool for studying interactions among diet, microbes, and host.

Copper metabolism and its implications for canine nutrition.

Canine copper nutrition has received increased attention due to recent reports of apparent copper-associated hepatitis in the USA and European Union. In order to properly address the need to modify the U.S. National Research Council and Association of American Feed Control Officials canine copper recommendations that will have implications for all dogs, it is important to understand the complexities of copper metabolism, confounding variables affecting copper status, and the available research on this topic in dogs. Recent trends in consumer preference for dog diets, supplements, and functional treats introduce another layer of complexity, as most ingredients used in these formulations provide vastly different proportions of essential nutrients, thus resulting in great variation in nutrient profiles available to the animal. Although controlled research addressing copper metabolism in dogs is limited, there are lessons to be learned from other monogastric species as well as canine case studies that can provide a base for increasing knowledge to address this issue. Copper metabolism and status in animals is affected by a multitude of factors including absorption, storage, excretion, and nutrient interactions. Given its vital role in many physiological processes, it is important that both nutritional deficiencies and toxicities be avoided. Additionally, another challenge for proper copper nutrition in dogs is the known genetic predispositions of some breeds for copper storage and excretion abnormalities. Therefore, it is imperative that veterinarians, nutritionists, and pet food manufacturers collaborate with the shared goal of providing dog food options that supply the essential nutrients at adequate concentrations to support an active and healthy life. Many questions remain regarding copper metabolism and proper diet formulation for dogs. Future research efforts should focus on discovering reliable, non-invasive methods for evaluating canine copper status, a deeper understanding of genetic predispositions of certain breeds, increased knowledge of copper contributions from various ingredients, and the role of unpredictable physiological stressors on copper metabolism.

The art of establishing mineral tolerances of dogs and cats.

For over six decades, nutritional science has provided well-developed, peer-reviewed nutrient recommendations to support the health of dogs and cats. These guidelines are updated based on new scientifically valid research and appropriate peer-review. Recent regulatory and scientific positions around health issues have resulted in strong opinions and desires for rapid regulatory action surrounding mineral nutrition, but with limited and conflicting scientific evidence. Pet Food Institute nutrition experts have come together to jointly author an article on the complexities of establishing mineral tolerances of dogs and cats to illustrate the limitations in defining mineral tolerances. This discussion covers how mineral requirements were determined, including the opportunities and pitfalls encountered. Scientific councils must review and clarify any proposed changes in conducting mineral nutrition research that might impact complete and balanced foods and surrounding regulations. It is important to clarify the multiple issues in mineral nutrition research and the necessity for thorough evaluation of data while avoiding arbitrary and potentially harmful guidelines.

Dogs and cats are living longer and healthier lives due, in part, to the scientific development of nutritional information. This information has allowed the building of many new types of foods, treats, and supplements that promote life, health, and enjoyment by the pet. There are several organizations that have provided helpful reviews of nutritional data through scientific councils that help identify safe and healthy criteria for all pet food products. These are readily available for those who want to learn more about pet nutrition. For many nutrients, there is a large database of information to help build products. Nutrients that are called macro- or micro-/trace minerals (e.g., sodium, potassium, zinc, copper, etc.) often have more limited information. Recently, strong opinions about pet health as related to mineral nutrition have been shared and robustly communicated without adequate scientific research to support the hypotheses. This has led to misinformation, concerns, and fear. To safeguard the health of companion animals and provide assistance to regulatory bodies regarding the nutritional welfare of dogs and cats, scientific panels have come together from industry, government, and academia to review, approve, and challenge nutritional guidelines. This overview provides the reader context into the rigor needed to establish safe mineral tolerances for dogs and cats.

Mode of delivery and early nutrition modulate microbial colonization and fermentation products in neonatal piglets.

Colonization of the intestinal microbiota after birth plays an important role in development of the neonatal gastrointestinal and immune systems. Two key environmental factors that influence the colonization pattern are delivery mode and nutrition. In this study, the impact of delivery mode and nutrition on microbial colonization and metabolic activity was investigated in the pig model. Vaginally (VD) or caesarean- (CD) delivered piglets were sow-reared (SR) or fed formula alone (FF) or with 4 g/L prebiotics [1:1 ratio of short-chain fructo-oligosaccharides (scFOS) and polydextrose (PDX); FP]. Intestinal contents were collected on d 7 and 14. SR piglets harbored different microbial populations from FF and FP piglets in ileum and ascending colon (AC). On d 7, FF piglets had a greater abundance of Clostridium XIVa in AC, but lower total bacteria, Clostridium XIVa, and Lactobacillus spp. in ileum and Fecalibacterium prausnitzii in AC compared with FP piglets. On d 14, total bacteria were more abundant in FP than FF piglets. Butyrate, isobutyrate, valerate, and isovalerate concentrations in AC were greater in SR piglets compared with FF or FP piglets. At both sampling days, acetate concentrations in AC were similar between the SR and FF groups, whereas propionate was higher in the SR compared with FF group. Delivery mode also significantly affected microbial populations. Bacterial densities differed in AC for Bacteroides-Prevotella at d 7 and Clostridium XIVa at d 14, being higher in VD piglets. Correspondingly, VD piglets had higher propionate in ileum and propionate and butyrate in AC compared with CD piglets. Our results indicate that both delivery mode and nutrition affect microbial composition and metabolic activity. Supplementation of scFOS/PDX to formula modulates microbial colonization and produces a SCFA pattern closer to that of SR piglets.

Effects of a synbiotic on fecal quality, short-chain fatty acid concentrations, and the microbiome of healthy sled dogs.

BACKGROUND: Sled dogs commonly suffer from diarrhea. Although multiple etiologies exist there are limited field studies using synbiotics as a supplement to prevent or treat diarrhea. The objective of this study was to examine alterations in fecal quality, short-chain fatty acids (SCFA), and the fecal microbiome in two groups of training sled dogs fed a synbiotic or microcrystalline cellulose placebo. Twenty clinically healthy training sled dogs randomized into two cohorts (9 synbiotic-fed, 8 placebo-fed) for a 6 week prospective study were examined. Fecal pH and fecal short chain fatty acid (SCFA) concentrations were measured and tag-encoded FLX 16S rDNA amplicon pyrosequencing (bTEFAP) and quantitative real-time PCR were performed at baseline (10 d prior to the study) and after 2 weeks of treatment with a total treatment time of 6 weeks. Fecal scores for all dogs were assessed at baseline and every day for 6 wk after initiation of treatment. RESULTS: Alterations in the fecal microbiome were observed with a significant rise in Lactobacillaceae in the synbiotic group (P = 0.004) after 2 wk of treatment. A positive correlation was found between Lactobacillaceae and overall butyrate concentration (R = 0.62, p = 0.011) in all dogs. After 5 wk of treatment, there was an improved fecal score and fewer days of diarrhea (Χ2 = 5.482, P = 0.019) in the dogs given synbiotic, which coincided with a presumed contagious outbreak shared by all dogs in the study. CONCLUSIONS: Use of this synbiotic results in an increase in presumed beneficial bacterial flora of the host colon which was associated with a decrease in the prevalence of diarrhea in training sled dogs.

Effects of dietary fiber on the feline gastrointestinal metagenome.

Four healthy adult cats were used in a crossover design to determine phylogeny and metabolic functional capacity of the cat's gastrointestinal microbiota using a metagenomic approach. Healthy adult cats (1.7 years old) were fed diets containing 4% cellulose, fructooligosaccharides (FOS), or pectin for 30 d, at which time fresh fecal samples were collected. Fecal DNA samples from each cat consuming each diet were subjected to 454 pyrosequencing. Dominant phyla determined using two independent databases (MG-RAST and IMG/M) included Firmicutes (mean=36.3 and 49.8%, respectively), Bacteroidetes (mean=36.1 and 24.1%, respectively), and Proteobacteria (mean=12.4 and 11.1%, respectively). Primary functional categories as determined by KEGG were associated with carbohydrates, clustering-based subsystems, protein metabolism, and amino acids and derivatives. Primary functional categories as determined by COG were associated with amino acid metabolism and transport, general function prediction only, and carbohydrate transport and metabolism. Analysis of carbohydrate-active enzymes revealed modifications in several glycoside hydrolases, glycosyl transferases, and carbohydrate-binding molecules with FOS and pectin consumption. While the cat is an obligate carnivore, its gut microbiome is similar regarding microbial phylogeny and gene content to omnivores.

Microbial composition and in vitro fermentation patterns of human milk oligosaccharides and prebiotics differ between formula-fed and sow-reared piglets.

The microbial composition and in vitro fermentation characteristics of human milk oligosaccharides (HMO), lacto-N-neotetraose (LNnT), a 2:1 mixture of polydextrose (PDX) and galactooligosaccharides (GOS), and short-chain fructooligosaccharides (scFOS) by pooled ascending colonic microbiota from 9- and 17-d-old formula-fed (FF) and sow-reared (SR) piglets were assessed. pH change and gas, SCFA, and lactate production were determined after 0, 2, 4, 8, and 12 h of incubation. In most donor groups, the pH change was greater for scFOS fermentation and lower for PDX/GOS than for other substrates. LNnT fermentation produced larger amounts of gas, total SCFA, acetate, and butyrate than did the other substrates, whereas HMO and scFOS produced higher amounts of propionate and lactate, respectively. In general, pH change, total SCFA, acetate, and propionate production were greater in pooled inoculum from FF and 9-d-old piglets, whereas SR-derived inoculum produced higher amounts of butyrate and lactate after 4 h fermentation. Gut microbiota were assessed by 16S ribosomal RNA V3 gene denaturing gradient gel electrophoresis analysis and real-time qPCR. Microbial structures differed among the 4 groups before fermentation, with higher counts of Bifidobacterium in SR piglets and higher counts of Clostridium cluster IV, XIVa, and Bacteroides vulgatus in FF piglets. Lactobacillus counts were higher in 9-d-old piglets than in 17-d-old piglets, regardless of diet. Bifidobacterium, Bacteroides, and clostridial species increased after 8 and 12 h fermentation on most substrates. In summary, piglet diet and age affect gut microbiota, leading to different fermentation patterns. HMO have potential prebiotic effects due to their effects on SCFA production and microbial modulation.

454 pyrosequencing reveals a shift in fecal microbiota of healthy adult men consuming polydextrose or soluble corn fiber.

The relative contribution of novel fibers such as polydextrose and soluble corn fiber (SCF) to the human gut microbiome and its association with host physiology has not been well studied. This study was conducted to test the impact of polydextrose and SCF on the composition of the human gut microbiota using 454 pyrosequencing and to identify associations among fecal microbiota and fermentative end-products. Healthy adult men (n = 20) with a mean dietary fiber (DF) intake of 14 g/d were enrolled in a randomized, double-blind, placebo-controlled crossover study. Participants consumed 3 treatment snack bars/d during each 21-d period that contained no supplemental fiber (NFC), polydextrose (PDX; 21 g/d), or SCF (21 g/d) for 21 d. There were no washout periods. Fecal samples were collected on d 16-21 of each period; DNA was extracted, followed by amplification of the V4-V6 region of the 16S rRNA gene using barcoded primers. PDX and SCF significantly affected the relative abundance of bacteria at the class, genus, and species level. The consumption of PDX and SCF led to greater fecal Clostridiaceae and Veillonellaceae and lower Eubacteriaceae compared with a NFC. The abundance of Faecalibacterium, Phascolarctobacterium, and Dialister was greater (P < 0.05) in response to PDX and SCF intake, whereas Lactobacillus was greater (P < 0.05) only after SCF intake. Faecalibacterium prausnitzii, well known for its antiinflammatory properties, was greater (P < 0.05) after fiber consumption. Principal component analysis clearly indicated a distinct clustering of individuals consuming supplemental fibers. Our data demonstrate a beneficial shift in the gut microbiome of adults consuming PDX and SCF, with potential application as prebiotics.

Acute satiety response of mammalian, avian and fish proteins in dogs.

Fish proteins have been reported to be more satiating than meat proteins. The objective was to determine the effect of different animal protein pre-meals on satiety. A total of ten intact female hounds were fed pork loin, beef loin, chicken breast, salmon fillet or pollock fillet. Each pre-meal was fed to contain 100 g protein. Blood was collected at 0, 5, 15, 30, 60, 90 and 120 min postprandially and analysed for glucose, insulin, total ghrelin, active glucagon-like peptide-1 (GLP-1) and plasma amino acids (AA). Dogs were fed 2 ×  metabolisable energy, 3 h following the pre-meal, and intake was determined 30, 60, 180 and 1440 min after food presentation. Glucose decreased over time (P < 0·001), but was lowest (P = 0·01) when dogs consumed pollock or chicken. Insulin increased (P < 0·0001) over time, and was greater (P = 0·09) when dogs consumed salmon. GLP-1 increased (P < 0·001) over time, and was greatest (P = 0·04) when dogs consumed beef. Ghrelin decreased (P < 0·0001) over time for all pre-meals. The tryptophan:large neutral AA ratio tended to be greater (P = 0·08) when dogs consumed pork, salmon and pollock. Different protein sources may influence blood markers in dogs, but it does not appear that fish substrates have different satiating abilities than mammalian or avian sources.

Perspective: Assessing Tolerance to Nondigestible Carbohydrate Consumption.

Human intestinal enzymes do not hydrolyze nondigestible carbohydrates (NDCs), and thus, they are not digested and absorbed in the small intestine. Instead, NDCs are partially to completely fermented by the intestinal microbiota. Select NDCs are associated with health benefits such as laxation and lowering of blood cholesterol and glucose. NDCs provide functional attributes to processed foods, including sugar or fat replacers, thickening agents, and bulking agents. Additionally, NDCs are incorporated into processed foods to increase their fiber content. Although consumption of NDCs can benefit health and contribute functional characteristics to foods, they can cause gastrointestinal symptoms, such as flatulence and bloating. As gastrointestinal symptoms negatively affect consumer well-being and their acceptance of foods containing NDC ingredients, it is crucial to consider tolerance when designing food products and testing their physiological health benefits in clinical trials. This perspective provides recommendations for the approach to assess gastrointestinal tolerance to NDCs, with a focus on study design, population criteria, intervention, comparator, and outcome. Special issues related to studies in children and implications for stakeholders are also discussed. It is recommended that the evaluation of gastrointestinal tolerance to NDCs be conducted in randomized, blinded, controlled crossover studies using standard gastrointestinal questionnaires, with attention to study participant background diets, health status, lifestyle, and medications.

Putting the whole grain puzzle together: health benefits associated with whole grains--summary of American Society for Nutrition 2010 Satellite Symposium.

The symposium "Putting the Whole Grain Puzzle Together: Health Benefits Associated with Whole Grains" sponsored by the ASN brought together researchers to review the evidence regarding the health benefits associated with whole grains. Current scientific evidence indicates that whole grains play an important role in lowering the risk of chronic diseases, such as coronary heart disease, diabetes, and cancer, and also contribute to body weight management and gastrointestinal health. The essential macro- and micronutrients, along with the phytonutrients present in whole grains, synergistically contribute to their beneficial effects. Current evidence lends credence to the recommendations to incorporate whole grain foods into a healthy diet and lifestyle program. The symposium also highlighted the need for further research to examine the role of whole grain foods in disease prevention and management to gain a better understanding of their mechanisms of action.

Digestive physiological outcomes related to polydextrose and soluble maize fibre consumption by healthy adult men.

The objective of the present study was to evaluate digestive physiological outcomes elicited by functional fibres fed to healthy adult men. A total of twenty-one healthy adult men were utilised in a cross-over design. Each subject received polydextrose (PDX) or soluble maize fibre (SCF) (21 g/d) or no supplemental fibre (no fibre control; NFC) in a snack bar. Periods were 21 d and faeces were collected during the last 5 d of each period. Food intake, including fibre intake, did not differ among treatments. Flatulence (P = 0·001) and distention (P = 0·07) were greatest when subjects consumed PDX or SCF. Reflux was greater (P = 0·04) when subjects consumed SCF compared with NFC. All tolerance scores were low ( < 2·5), indicating only slight discomfort. Faecal ammonia, 4-methylphenol, indole and branched-chain fatty acid concentrations were decreased (P < 0·01) when subjects consumed the functional fibre sources compared with NFC. Faecal acetate, propionate and butyrate concentrations were lower (P < 0·05) when subjects consumed PDX compared with SCF and NFC. Faecal pH was lower (P = 0·01) when subjects consumed SCF compared with NFC, while PDX was intermediate. Faecal wet weight was greatest (P = 0·03) when subjects consumed SCF compared with NFC. Faecal dry weight tended to be greater (P = 0·07) when subjects consumed PDX compared with NFC. The functional fibres led to 1·4 and 0·9 g (PDX and SCF, respectively) increases in faecal dry mass per g supplemental fibre intake. Bifidobacterium spp. concentrations were greater (P < 0·05) when subjects consumed SCF compared with NFC. These functional fibres appear to be beneficial to gut health while leading to minimal gastrointestinal upset.

Physiological recovery from firefighting activities in rehabilitation and beyond.

OBJECTIVES: The primary objective of this study was to document the timeline of physiologic recovery from firefighting activities in order to inform emergency medical services (EMS) of vital sign values that might be expected during incident rehabilitation and in developing rehabilitation protocols to make decisions about when to return personnel to the fireground. Secondarily, we compared two different incident rehabilitation strategies to determine effectiveness in reducing physiologic strain following firefighting. METHODS: A repeated-measures randomized crossover design was utilized in which firefighters conducted a controlled set of firefighting activities, after which they completed incident rehabilitation in one of two conditions: 1) similar to currently used rehabilitation protocols and 2) with active cooling and nutritional intervention. Following 15 minutes of rehabilitation, each firefighter was asked to perform a simulated rescue "dummy drag" and then recover for 120 minutes in a quiet area. Core temperature and heart rate were recorded throughout the study. Blood pressures and subendocardial viability ratios were obtained before firefighting, after firefighting, and at standardized times during rehabilitation and recovery. RESULTS: Heart rate and core temperature increased during firefighting, and core temperature continued to increase for 7 minutes after completion of firefighting activities. These values did not return to baseline until at least 50 minutes after firefighting activity. Systolic blood pressures were significantly reduced during rehabilitation (15.2%), and recovered 7.7% during the first 30 minutes of recovery, but remained significantly lower than before firefighting for at least 120 minutes. An index of subendocardial perfusion was also significantly depressed for up to 110 minutes after firefighters. Differences between rehabilitation protocols were minimal. CONCLUSIONS: The timeline for recovery from firefighting activities is significantly longer than the typical 10-20-minute rehabilitation period that often is provided on the fireground. Modifications from the current rehabilitation protocol do not appear to improve the recovery timeline when rehabilitation is conducted in a cool room. While firefighters often are concerned about elevated blood pressures, this study suggests that firefighters and EMS personnel should also be cognizant of the potential dangers of hypotension.

Sickness behavior induced by endotoxin can be mitigated by the dietary soluble fiber, pectin, through up-regulation of IL-4 and Th2 polarization.

Peripheral activation of the immune system by infectious agents triggers the brain-cytokine system causing sickness behaviors which profoundly impact well-being. Dietary fiber is a beneficial foodstuff that, from a gastrointestinal tract perspective, exists in both insoluble and soluble forms. We show that a diet rich in soluble fiber protects mice from endotoxin-induced sickness behavior by polarizing mice Th2 when compared to a diet containing only insoluble fiber. Mice fed soluble fiber became less sick and recovered faster from endotoxin-induced sickness behaviors than mice fed insoluble fiber. In response to intraperitoneal endotoxin, mice fed soluble fiber had up-regulated IL-1RA and reduced IL-1beta and TNF-alpha in the brain as compared to mice fed insoluble fiber. Importantly, mice fed soluble fiber had a basal increase in IL-4 in the ileum and spleen which was absent in MyD88 knockout mice. Con-A stimulated splenocytes from mice fed soluble fiber showed increased IL-4 and IL-5 and decreased IL-2, IL-12 and IFN-gamma when compared to mice fed insoluble fiber. Likewise, endotoxin-stimulated macrophages from mice fed soluble fiber demonstrated decreased IL-1beta, TNF-alpha, IFN-gamma, IL-12 and nitrate and increased IL-1RA, arginase 1 and Ym1 when compared to mice fed insoluble fiber. Finally, the behavioral protection afforded by feeding mice soluble fiber was reduced in IL-4 knockout mice, as was the impact of soluble fiber on Con-A stimulated splenocytes and endotoxin activated macrophages. These data show that a diet rich in soluble fiber protects against endotoxin-induced sickness behavior by polarizing mice Th2 and promoting alternative activation of macrophages.

Laxative effects of wheat bran and psyllium: Resolving enduring misconceptions about fiber in treatment guidelines for chronic idiopathic constipation.

BACKGROUND: Treatment guidelines for chronic idiopathic constipation (CIC) recommend an "increase in fiber intake" as a first-line therapy, but most epidemiologic studies fail to support an association between a high-fiber diet and a reduced risk of constipation. Furthermore, randomized controlled clinical studies show that most isolated fibers (e.g., supplements) are not different from placebo for a laxative effect, and several may be constipating. OBJECTIVES: The objective of this review was to compare the effects of two isolated fibers, coarse wheat bran and psyllium, on stool output and stool water content in patients with CIC. This review will also address misconceptions about fiber that are perpetuated by treatment guidelines. DATA SOURCES: A comprehensive literature review was conducted with the use of the Scopus, SciFinder, and PubMed scientific databases, limited to the previous 50 years (1968-2018; latest date included, December 31, 2018). CONCLUSIONS: In patients with CIC, nonfermented gel-forming psyllium was 3.4 times more effective than insoluble wheat bran for increasing stool output. Both psyllium and coarse wheat bran increased stool water content, a stool-softening effect, but finely ground wheat bran decreased stool water content, a stool-hardening effect. IMPLICATIONS FOR PRACTICE: It is a misconception that dietary fiber and all isolated fibers provide a laxative effect in patients with CIC. Our analysis suggests that treatment guidelines for CIC should make specific evidence-based recommendations as it pertains to fiber. To do otherwise takes the risk of perpetuating myth and misunderstanding and depriving patients of an effective therapy for CIC. A generic recommendation to "increase fiber intake" is akin to a recommendation to "increase pill intake" without regard to therapeutic or adverse effects.

ASAS-NANP SYMPOSIUM: RUMINANT/NONRUMINANT FEED COMPOSITION: Challenges and opportunities associated with creating large feed composition tables.

Traditional feed composition tables have been a useful tool in the field of animal nutrition throughout the last 70 yr. The objective of this paper is to discuss the challenges and opportunities associated with creating large feed ingredient composition tables. This manuscript will focus on three topics discussed during the National Animal Nutrition Program (NANP) Symposium in ruminant and nonruminant nutrition carried out at the American Society of Animal Science Annual Meeting in Austin, TX, on July 11, 2019, namely: 1) Using large datasets in feed composition tables and the importance of standard deviation in nutrient composition as well as different methods to obtain accurate standard deviation values, 2) Discussing the importance of fiber in animal nutrition and the evaluation of different methods to estimate fiber content of feeds, and 3) Description of novel feed sources, such as insects, algae, and single-cell protein, and challenges associated with the inclusion of such feeds in feed composition tables. Development of feed composition tables presents important challenges. For instance, large datasets provided by different sources tend to have errors and misclassifications. In addition, data are in different file formats, data structures, and feed classifications. Managing such large databases requires computers with high processing power and software that are also able to run automated procedures to consolidate files, to screen out outlying observations, and to detect misclassified records. Complex algorithms are necessary to identify misclassified samples and outliers aimed to obtain accurate nutrient composition values. Fiber is an important nutrient for both monogastrics and ruminants. Currently, there are several methods available to estimate the fiber content of feeds. However, many of them do not estimate fiber accurately. Total dietary fiber should be used as the standard method to estimate fiber concentrations in feeds. Finally, novel feed sources are a viable option to replace traditional feed sources from a nutritional perspective, but the large variation in nutrient composition among batches makes it difficult to provide reliable nutrient information to be tabulated. Further communication and cooperation among different stakeholders in the animal industry are required to produce reliable data on the nutrient composition to be published in feed composition tables.