Intestinal Fermentation Research Articles

Prediction of digestible and metabolizable energy of corn distillers dried grains with solubles for growing pigs using in vitro digestible nutrients.

The objective of this study was to develop prediction equations (EQS) that estimate DE and ME content of corn distillers dried grains with solubles (DDGS) using digestible (DIG) nutrients from in vitro or in vivo assays. Chemical composition data from 12 sources of corn DDGS were obtained using laboratory chemical analysis (LCA) and near infrared spectroscopy (NIRS). In vitro DM disappearance (IVDMD) from gastric and small intestine hydrolysis (IVDMDh), large intestine fermentation (IVDMDf), and total tract digestion (IVDMDt) were also determined along with in vivo apparent total tract digestibility (ATTD) of DM, CP, ether extract (EE), NDF, and ADF, and energy values (GE, DE, and ME). Correlation analysis was used to compare chemical composition from LCA with NIRS, and a stepwise selection of variables was performed using linear regression to establish DE and ME prediction EQS. Composition determined by NIRS did not correlate with values from LCA. Consequently, significance and R2 were poorer when using NIRS data as inputs to predict DE (P = 0.11; R2 = 0.23) and ME (P = 0.11; R2 = 0.24). However, when using LCA data, DE (P = 0.04; R2 = 0.35) and ME (P = 0.04; R2 = 0.52) estimates of corn DDGS obtained from prediction EQS had significant P values, but low R2. Better prediction of DE (P < 0.01; R2 = 0.83) and ME (P < 0.01; R2 = 0.76) was observed when using in vivo DIG nutrients as inputs (DM basis) for DE, kcal/kg = 854.5 + (3.6 × DIG DM, g/kg) + (3.7 × DIG EE, g/kg) + (2.0 × DIG NDF, g/kg) and ME, kcal/kg = 704.5 + (3.3 × DIG DM, g/kg) + (4.8 × DIG EE, g/kg) + (2.6 × DIG NDF, g/kg). In vitro DIG DM, but not in vitro DIG NDF, was selected for use in EQS (7) DE, kcal/kg = 6,383.6 - (42.5 × in vitro DIG DM, g/kg) + (35.4 × DIG EE, g/kg) and (8) ME, kcal/kg = 6,635.1 - (49.8 × in vitro DIG DM, g/kg) + (41.3 × DIG EE, g/kg), but the significance and accuracy for both DE (P = 0.07; R2 = 0.45) and ME (P = 0.05; R2 = 0.49) predictions was less using in vitro DIG nutrient values than using in vivo DIG nutrient values. If chemical composition was used to replace in vivo EE, along with in vitro DIG NDF and DM, the prediction EQS only used the concentration of ADF and EE as predictors instead of in vitro DIG NDF and DM. In conclusion, in vivo DIG NDF, DM, and EE are the best predictors for DE and ME content of corn DDGS for swine. Using NIRS to determine chemical composition, in vitro DIG NDF, and in vitro DIG DM did not result in accurate predictions of DE and ME.

Metabolic response to amylose-rich wheat-based rusks in overweight individuals.

The amylose-amylopectin ratio influences starch properties. A higher amylose content is associated with slower starch digestion thus reducing the postprandial plasma glucose response and improving the overall postprandial metabolism. So far, limited evidence is available on the metabolic effect of wheat-based foods rich in amylose. This randomised controlled study investigated the acute metabolic effects of amylose-rich wheat-based rusks in overweight subjects focusing on potential mechanisms. Ten overweight subjects consumed in random order two test meals differing only in the carbohydrate source: rusks prepared with amylose-rich wheat flour (ARR) or conventional wheat flour (control). Blood samples were taken at fasting and over 4 h after the meal. Satiety and intestinal fermentation were evaluated by VAS and H2-breath test, respectively. ARR reduced plasma glucose response during the first two hours after the meal and the desire to eat, and increased breath hydrogen concentration at 4 h (p < 0.05 for all). Moreover, according to computational models, the ARR slightly reduced intestinal glucose absorption in the first hour after the meal and increased the overall postprandial insulin sensitivity. Rusks made with amylose-rich flour could be useful for improving postprandial glucose metabolism and reduce the desire to eat, thus possibly contributing to the prevention and treatment of overweight/obesity, impaired glucose tolerance or diabetes.

Removal of the cecum affects intestinal fermentation, enteric bacterial community structure, and acute colitis in mice

ABSTRACTThe murine cecum is a major site of fermentation of dietary materials, and production of short chain fatty acids (SCFAs). To examine the role that the cecum plays in acute bacterial infection in mice, the cecum was surgically removed, and changes in bacterial communities and production of SCFAs were analyzed relative to surgical sham animals. To incite bacterial colitis, mice were orally challenged with Citrobacter rodentium. The impact of butyrate administered directly into the colon was also examined. Concentrations of SCFAs in feces were substantially lower in mice with an excised cecum. Bacterial communities were also less diverse in cecectomized mice, and densities of major SCFA-producing taxa including bacteria within the Ruminococcaceae and Lachnospiraceae families were reduced. Colonization of the intestine by C. rodentium was not affected by removal of the cecum, and the bacterium equally incited acute colitis in mice with and without a cecum. However, cecectomized mice exhibited lower body weights at later stages of infection indicating an impaired ability to recover following challenge with C. rodentium. Furthermore, removal of the cecum altered immune and inflammatory responses to infection including increased inflammatory markers in the proximal colon (Tnfα, Il10, βd1), and heightened inflammatory response in the proximal and distal colon (Ifnγ, Tnfα, Relmβ). Exogenous administration of butyrate was insufficient to normalize responses to C. rodentium in cecectomized mice. The murine cecum plays a critical role in maintaining intestinal health, and the murine cecectomy model may be a useful tool in elucidating key aspects of intestine-pathogen-microbiota interactions.

Effect of a combination of inulin and polyphenol-containing adzuki bean extract on intestinal fermentation in vitro and in vivo.

The effect of a combination of inulin (INU) and polyphenol-containing adzuki bean extract (AE) on intestinal fermentation was examined in vitro using fermenters for 48h and in vivo using rats for 28 d. The total short-chain fatty acid concentrations in the fermenters were decreased by a combination of INU and AE, but the concentration in the INU+AE group was higher than the cellulose (CEL) and CEL+AE groups. The cecal propionate concentration was increased by a combination of INU and AE compared with their single supplement. The ammonia-nitrogen concentration in the fermenters and rat cecum was decreased by INU and AE. Cecal mucin levels were increased by INU and AE respectively. Therefore, our observations suggested that the combination of INU and AE might be a material of functional food that includes several healthy effects through intestinal fermentation.

Butyrate from pectin fermentation inhibits intestinal cholesterol absorption and attenuates atherosclerosis in apolipoprotein E-deficient mice

Short-chain fatty acids (SCFAs), the major products of dietary fiber fermentation by intestinal microflora, exert beneficial effects on pathogenesis of multiple metabolic diseases. The aim of this study was to determine whether SCFAs from fermentation of pectin (PE), a soluble dietary fiber, prevent the development of atherosclerosis in apolipoprotein E-deficient (apoE−/−) mice. Male apoE−/− mice (8-week-old) were fed a high-fat, high-cholesterol diet (HCD; 21% wt/wt fat, 0.15% wt/wt cholesterol) or HCD supplemented with 20% wt/wt PE (HCD+PE) alone or with antibiotics (HCD+PE + A) in drinking water for 12 weeks. Serum lipids and SCFAs concentrations, atherosclerotic lesion area, and intestinal morphology and function were measured. Caco-2 cells were treated with SCFAs to determine whether they affected the expression of genes involved in cholesterol absorption. HCD+PE-treated mice exhibited decreased serum total and low-density lipoprotein cholesterol, and reduced atherosclerotic lesion area compared with HCD mice. These beneficial effects of PE were not observed in the HCD+PE+A group. Incubation of Caco-2 cells with butyrate, but not acetate and propionate, down-regulated the expression of Niemann-Pick C1-Like 1 but up-regulated the ATP-binding cassette transporters G5 and G8 (ABCG5 and G8) at the mRNA level. Butyrate treatment also increased transcriptional activity of liver X receptor in Caco-2 cells. Our data suggest that butyrate from PE intestinal fermentation protects mice from the progression of diet-induced atherosclerosis in apoE−/− mice. These findings suggest a novel mechanism by which dietary fiber may prevent the development of atherosclerosis.

Reducing agent can be omitted in the incubation medium of the batch in vitro fermentation model of the pig intestines

Over the past decade, in vitro methods have been developed to study intestinal fermentation in pigs and its influence on the digestive physiology and health. In these methods, ingredients are fermented by a bacterial inoculum diluted in a mineral buffer solution. Generally, a reducing agent such as Na2S or cysteine-HCl generates the required anaerobic environment by releasing metabolites similar to those produced when protein is fermented, possibly inducing a dysbiosis. An experiment was conducted to study the impact of two reducing agents on results yielded by such in vitro fermentation models. Protein (soybean proteins, casein) and carbohydrate (potato starch, cellulose) ingredients were fermented in vitro by bacteria isolated from fresh feces obtained from three sows in three carbonate-based incubation media differing in reducing agent: (i) Na2S, (ii) cysteine-HCl and (iii) control with a mere saturation with CO2 and devoid of reducing agent. The gas production during fermentation was recorded over 72 h. Short-chain fatty acids (SCFA) production after 24 and 72 h and microbial composition of the fermentation broth after 24 h were compared between ingredients and between reducing agents. The fermentation residues after 24 h were also evaluated in terms of cytotoxicity using Caco-2 cell monolayers. Results showed that the effect of the ingredient induced higher differences than the reducing agent. Among the latter, cysteine-HCl induced the strongest differences compared with the control, whereas Na2S was similar to the control for most parameters. For all ingredients, final gas produced per g of substrate was similar (P>0.10) for the three reducing agents whereas the maximum rate of gas production (Rmax) was reduced (P<0.05) when carbohydrate ingredients were fermented with cysteine-HCl in comparison to Na2S and the control. For all ingredients, total SCFA production was similar (P>0.10) after 24 h of fermentation with Na2S and in the control without reducing agent. Molar ratios of branched chain-fatty acids were higher (P<0.05) for protein (36.5% and 9.7% for casein and soybean proteins, respectively) than for carbohydrate (<4%) ingredients. Only fermentation residues of casein showed a possible cytotoxic effect regardless of the reducing agent (P<0.05). Concerning the microbial composition of the fermentation broth, most significant differences in phyla and in genera ascribable to the reducing agent were found with potato starch and casein. In conclusion, saturating the incubation media with CO2 seems sufficient to generate a suitable anaerobic environment for intestinal microbes and the use of a reducing agent can be omitted.

UHPLC-ESI-QTOF-MS profile of polyphenols in Goji berries (Lycium barbarum L.) and its dynamics during in vitro gastrointestinal digestion and fermentation

The phenolic profile of Goji berries from Italy and China was investigated through ultra-high-pressure liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry. Hydroxycinnamic acids, followed by flavonols and flavanols, were the most representative phenolics, whereas glycoside forms of anthocyanins and flavonols were the compounds best discriminating between Chinese and Italian berries.A mix of dried berries was then subjected to in vitro gastro-intestinal digestion and fermentation to investigate the fate and bioaccessibility of phenolic compounds. The total phenolic content and the oxygen radical absorbance capacity recorded during the large intestine fermentation increased at 24 h, up to 1.56 mg gallic acid equivalents g−1 and 1.76 μmol trolox equivalents g−1, respectively. Multivariate statistics applied to phenolic profiling during the in vitro fermentation depicted those compounds having the highest bioaccessibility; stilbenes, alkyl-resorcinols and lignans were the best markers of Goji berries during in vitro fermentation.

Use of in vitro dry matter digestibility and gas production to predict apparent total tract digestibility of total dietary fiber for growing pigs.

In vitro DM disappearance (IVDMD) and gas production methods have been developed and used to measure in vivo nutrient digestibility of feed ingredients, but further validation is needed for ingredients containing high concentrations of insoluble fiber such as corn distiller's dried grains with solubles (DDGS). A 3-step in vitro procedure and resulting gas production were used to predict in vivo apparent total tract digestibility (ATTD) of total dietary fiber (TDF) among 3 sources each of wheat straw (WS), soybean hulls (SBH), and DDGS. A total of 34 barrows and 2 gilts (84 ± 7 kg BW) were used in a changeover design to determine the ATTD of 9 dietary treatments. The WS, SBH, or DDGS sources were the only ingredients containing fiber in each diet, and all diets were formulated to contain the same TDF concentration (22.3%). The in vivo experiment was conducted in 2 consecutive 13-d periods, each including a 10-d adaptation and a 3-d collection period to provide 8 replications/dietary treatment, and 0.5% TiO was added to each diet as an indigestible marker. Pigs had ad libitum access to water and were fed an amount of feed equivalent to 2.5% of initial BW in each period. The in vitro experiment was used to determine IVDMD and gas production of the 9 ingredients (5 to 8 replicates/ingredient) fed during the in vivo experiment. Gas production kinetics were fitted using a nonlinear model and analyzed using a mixed model, and predictions were evaluated using correlations and regression models. There were differences ( < 0.01) in ATTD of TDF among WS (26.7%), SBH (78.9%), and DDGS (43.0%) and among sources of DDGS (36.0 to 49.8%). Differences ( < 0.05) in IVDMD from simulated gastric and small intestinal hydrolysis were observed among WS (13.3%), SBH (18.9%), and DDGS (53.7%) and among sources of WS (12.8 to 13.8%), SBH (17.0 to 20.5%), and DDGS (52.0 to 56.9%). Differences ( < 0.05) in IVDMD from simulated large intestine fermentation (IVDMDf) were also observed among WS (23.3%), SBH (84.6%), and DDGS (69.6%) and among sources of WS (18.7 vs. 26.8%). In vitro DM disappearance from simulated total tract digestion of SBH (88.9%) and DDGS (86.1%) were greater ( < 0.01) than that of WS (33.5%). Differences ( < 0.01) in asymptotic gas production (A; mL/g DM substrate) were observed among WS (121), SBH (412), and DDGS (317), and ATTD of TDF was highly correlated with IVDMDf and A. In conclusion, low variability in ATTD of TDF and IVDMD among sources of WS and SBH evaluated in the current study may not justify the use of in vitro measurements, but in vitro fermentation accurately predicts ATTD of TDF among sources of corn DDGS.

Dietary Uncoupling of Gut Microbiota and Energy Harvesting from Obesity and Glucose Tolerance in Mice

SummaryEvidence suggests that altered gut microbiota composition may be involved in the development of obesity. Studies using mice made obese with refined high-fat diets have supported this; however, these have commonly used chow as a control diet, introducing confounding factors from differences in dietary composition that have a key role in shaping microbiota composition. We compared the effects of feeding a refined high-fat diet with those of feeding either a refined low-fat diet or a chow diet on gut microbiota composition and host physiology. Feeding both refined low- or high-fat diets resulted in large alterations in the gut microbiota composition, intestinal fermentation, and gut morphology, compared to a chow diet. However, body weight, body fat, and glucose intolerance only increased in mice fed the refined high-fat diet. The choice of control diet can dissociate broad changes in microbiota composition from obesity, raising questions about the previously proposed relationship between gut microbiota and obesity.

Bioaccessibility of phenolic compounds following in vitro large intestine fermentation of nuts for human consumption

A bioaccessibility study of polyphenols after in vitro simulated large intestine fermentation was carried out on edible nuts. Raw nuts were also analysed for total phenolic content and antioxidant potential, considering both bound and free phenolics. The highest phenolic content was found in walnuts, followed by pistachios extracts (596.9 and 410.1 mg gallic acid equivalents 100 g−1, respectively). Consistently, the total antioxidant capacity was highest in walnuts (3689.7 μM trolox equivalents 100 g−1) followed by peanuts and pistachios (3169.6 and 2990.1 μM trolox equivalents 100 g−1, respectively). Data showed high correlations between total phenolics and both antioxidant activities. The metabolomics-based phenolic profile depicted during in vitro fermentation showed a degradation of higher-molecular-weight phenolics over 48 hours of faecal fermentation, with a concurrent increase in low-molecular-weight compounds (hydroxybenzoic and hydroxycinnamic acids, alkylphenols, and tyrosols). Our findings indicate that nuts deliver polyphenols into the colon, with bioaccessibility values not negligible for alkylphenols, tyrosols and phenolic acids.

Cryopreservation of artificial gut microbiota produced with invitro fermentation technology.

SummaryInterest in faecal microbiota transplantation (FMT) has increased as therapy for intestinal diseases, but safety issues limit its widespread use. Intestinal fermentation technology (IFT) can produce controlled, diverse and metabolically active ‘artificial’ colonic microbiota as potential alternative to common FMT. However, suitable processing technology to store this artificial microbiota is lacking. In this study, we evaluated the impact of the two cryoprotectives, glycerol (15% v/v) and inulin (5% w/v) alone and in combination, in preserving short‐chain fatty acid formation and recovery of major butyrate‐producing bacteria in three artificial microbiota during cryopreservation for 3 months at −80°C. After 24 h anaerobic fermentation of the preserved microbiota, butyrate and propionate production were maintained when glycerol was used as cryoprotectant, while acetate and butyrate were formed more rapidly with glycerol in combination with inulin. Glycerol supported cryopreservation of the Roseburia spp./Eubacterium rectale group, while inulin improved the recovery of Faecalibacterium prausnitzii. Eubacterium hallii growth was affected minimally by cryopreservation. Our data indicate that butyrate producers, which are key organisms for gut health, can be well preserved with glycerol and inulin during frozen storage. This is of high importance if artificially produced colonic microbiota is considered for therapeutic purposes.

Digestibility and intestinal fermentability of canola meal from Brassica juncea and Brassica napus fed to ileal-cannulated grower pigs

Yellow-seeded Brassica (B.) juncea is a novel canola species. Therefore, its meal co-product requires feed quality evaluation and comparison to conventional, dark-seeded B. napus canola meal for pigs. The B. juncea canola meal contains less fibre than B. napus canola meal (190 vs. 260g NDF/kg, as is), but also less lysine (20.3 vs. 22.1g/kg). Nutrient digestibility and fermentibility of B. juncea and B. napus canola meal were assessed in a 2×2factorial arrangement. Six ileal-cannulated pigs (47kg BW) were fed six diets in a 6×6 Latin square: basal diet (460g wheat/kg and corn starch), 4 diets with 460g wheat/kg and either B. juncea or B. napus canola meal at 250 or 500g/kg replacing corn starch, sugar and canola oil, and an N-free diet based on corn starch. The B. juncea canola meal had greater (P<0.05) CATTD of gross energy than B. napus canola meal (0.70 vs. 0.63) most likely due to its lower fibre content. Ileal total VFA concentration was lower (P<0.001) in pigs fed B. juncea than B. napus canola meal diets (15.2 vs. 20.8μmol/g of wet digesta). In pigs fed B. juncea canola meal instead of B. napus canola meal diets, the molar ratio was greater (P<0.01) for digesta propionate and faecal acetate, but lower (P<0.05) for digesta and faecal butyrate. Canola meal species did not affect the CAID of gross energy, CSID of amino acid and faecal VFA content. The digestible energy (DE) value was greater (P<0.01; 12.1 vs. 10.9MJ/kg, standardised to 100g/kg moisture) for B. juncea than B. napus canola meal. Increasing dietary inclusion of canola meal up to 500g/kg reduced (P<0.01) diet digestibility of gross energy but not amino acids and decreased (P<0.05) intestinal fermentability of B. napus but not B. juncea. In conclusion, B. juncea canola meal had greater fermentability and ATTD of gross energy than B. napus canola meal, but digestibility of amino acids did not differ. Increasing dietary inclusion of canola meal up to 500g/kg reduced digestibility of gross energy but not digestibility of AA. Fermentability of B. napus canola meal but not B. juncea canola meal decreased in the pig intestine with increased dietary inclusion. Hence, yellow-seeded B. juncea canola meal had a greater DE value, similar amino acid digestibility as conventional dark-seed B. napus canola meal and may limit protein fermentation in the pig intestine.

Flaxseed meal and oat hulls supplementation modulates growth performance, blood lipids, intestinal fermentation, bile acids, and neutral sterols in growing pigs fed corn-soybean meal-based diets.

The present study was conducted to determine the effect of flaxseed meal and oat hulls supplementation on growth performance, apparent total tract digestibility (ATTD) of fat, serum lipids, and concentrations of VFA, bile acids (BA), and neutral sterols (NS) in digesta and feces in growing pigs. Forty-eight Genesus [(Duroc boar × Yorkshire-Landrace sows] barrows (25.0 ± 0.32 kg initial BW) were housed in pairs. Pigs were assigned to 1 of the 3 corn-soybean meal-based diets-a basal corn-soybean meal-containing diet (control), a flaxseed meal-containing diet (FM), or an oat hulls-containing diet (OH)-in a completely randomized design. All diets were formulated to be isoenergetic and to contain similar standardized ileal digestible AA contents and meet other nutrient requirements for growing pigs. The experiment lasted for 28 d. Average daily feed intake; ADG; G:F; ATTD of fat, serum lipids, and digesta; and fecal VFA, BA, and NS concentrations were determined. Pigs fed the control or OH had greater final BW ( < 0.001), ADFI ( = 0.005), and ADG ( < 0.001) than FM-fed pigs. The ATTD of fat in the FM was lowest at 70.1% followed by 79.2% in OH and was greatest at 92.4% in the control ( = 0.020). Total serum cholesterol content was 2.25 and 1.99 mmol/L and lower ( < 0.001) in pigs fed FM and OH, respectively, than the 2.36 mmol/L in pigs fed the control. Pigs fed the FM and OH had greater ileal and cecal total VFA ( < 0.001), ileal deoxycholic acid ( < 0.01), and cecal ( < 0.001) and fecal cholesterol ( = 0.002) concentrations than those fed the control. Pigs fed the FM excreted more fecal lithocholic acid ( = 0.002) and ursodeoxycholic acid ( = 0.001) compared with those that consumed the control and OH. The concentrations of coprostanol in cecal digesta ( < 0.001) and feces ( = 0.011) were higher in pigs fed the FM and OH than in pigs fed the control. In conclusion, feeding flaxseed meal and oat hulls induced intestinal fermentation; however, the former depressed growth performance whereas the latter did not have any effect. Addition of flaxseed meal and oat hulls in growing pig diets reduced fat digestibility and serum cholesterol and stimulated malabsorption of primary BA and excretion of secondary BA and NS.

Gut Microbial Transformation of the Dietary Imidazoquinoxaline Mutagen MelQx Reduces Its Cytotoxic and Mutagenic Potency.

The diverse community of microbes present in the human gut has emerged as an important factor for cancer risk, potentially by altering exposure to chemical carcinogens. In the present study, human gut bacteria were tested for their capacity to transform the carcinogenic heterocyclic amine 2-Amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MelQx). Eubacterium hallii, Lactobacillus reuteri, and Lactobacillus rossiae were able to convert MelQx to a new microbial metabolite characterized on the basis of high-resolution mass spectrometry and NMR as 9-hydroxyl-2,7-dimethyl-7,9,10,11-tetrahydropyrimido[2′,1′:2,3]imidazo[4,5-f]quinoxaline (MelQx-M1), resulting from conjugation with activated glycerol. Acrolein derived from the decomposition of 3-hydroxypropionaldehyde, which is the product of bacterial glycerol/diol dehydratase activity, was identified as the active compound responsible for the formation of MelQx-M1. A complex human gut microbial community obtained from invitro continuous intestinal fermentation was found to also transform MelQx to MelQx-M1. MelQx-M1 had slightly reduced cytotoxic potency toward human colon epithelial cells invitro, and diminished mutagenic potential toward bacteria after metabolic activation. As bacterially derived acrolein also transformed 2 other HCAs, namely 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine and 2-amino-3-methylimidazo[4,5-f]quinoline, these results generalize the capacity of gut microbiota to detoxify HCAs in the gut, potentially modulating cancer risk.

The microbial fermentation characteristics depend on both carbohydrate source and heat processing: a model experiment with ileo-cannulated pigs

The effects of carbohydrate (CHO) source and processing (extrusion cooking) on large intestinal fermentation products were studied in ileo-cannulated pigs as a model for humans. Pigs were fed diets containing barley, pea or a mixture of potato starch:wheat bran (PSWB) either raw or extrusion cooked. Extrusion cooking reduced the amount of starch fermented in the large intestine by 52–96% depending on the CHO source and the total pool of butyrate in the distal small intestine + large intestine by on average 60% across diets. Overall, extrusion cooking caused a shift in the composition of short-chain fatty acids (SCFA) produced towards more acetate and less propionate and butyrate. The CHO source and processing highly affected the fermentation characteristics and extrusion cooking generally reduced large intestinal fermentation and resulted in a less desirable composition of the fermentation products. The latter outcome is non-conducive to a healthy large intestinal environment and its resulting metabolic health.

Beneficial Effects of Fermentation of Whole Grains (WG) and Whole Grain Resistant Starch (RS) in Lean Zucker Diabetic Fatty (ZDF) Rats

Whole grain components have been shown to have a beneficial role concurrent with and independent of purified resistant starch (RS2) through intestinal fermentation when delivered as a fermentable dietary fiber. As Americans consume less than half of the recommended amounts of fiber, determining if a lower fiber dose can still provide benefits through use of WG and RS may still allow for health benefits in the context of lower intake. The current study was designed to delineate optimal health effects from a whole grain prebiotic using a dose response, where the beneficial effects of fermentation were expected to be observed beginning at 5% (wt diet). Estimates for comparing fiber in humans vs. rats are ~10% for equivalence. Previous studies with obese ZDF rats showed robust effects of fermentation on gut microbiota with no reduction of abdominal fat when fed RS. Additionally, Sprague Dawley (SD) rats demonstrated a significantly increased fermentation, though not as robust as ZDF rats, when fed WG, RS, and WG+RS diets, but also statistically significant differences in abdominal body fat as compared to obese ZDF rats. Isocaloric moderate fat (3.7 kcal/g, ~30% of energy) diets were developed with the following starch sources: control starch with no WG or RS [CON], natural WG waxy corn flour with low RS (35.1 %WG) [WGC], or increasing levels of a whole grain high amylose maize resistant starch (WGRS) [HMWG: 5 (9.3), 10 (18.6), 15 (27.9), 20% (37.2%) RS (%WG)]. The six diets were fed to lean ZDF rats for eight weeks (n=11; n=12 for 5%, 10% HMWG). Single degree of freedom contrasts (WGC vs. CON, 5%, 10%, 15%, 20%) were performed at p&lt;0.05. Beginning at 5% HWMG, pH had significant reduction as compared to WGC. Cecum weight significantly increased from 10% HMWG on. All short chain fatty acid (SCFA) measurements were significantly different for WG vs. CON. SCFA acetate and propionate showed a significant increase at 5% and increased consecutively through 20%, while butyrate increased at 15% and 20%. No significant differences were observed for food and energy intake and percentage abdominal fat/emboweled body wt (gut contents removed). At 5% HMWG, fermentation effects differed overall from the WG control. An indirect comparison of lean ZDF rats and obese ZDF rats has shown similarity in fermentation and no changes in body fat. As WGRS dosage increased, gut health benefits (fermentation parameters) increased, but did not affect food and energy consumed or abdominal fat. WG flour alone promoted fermentation with RS1, a component of the WG kernel, and WGRS (RS1+RS2) promoted greater fermentation. Replacing traditional starch for a whole grain starch is beneficial, while replacing it with a whole grain with resistant starch, as low as 5%, is better. These results suggest that a lower level of intake of fermentable fiber as RS is beneficial, but show that substantial WG (35.1%) with only low RS1 (2%) also had beneficial effects.Support or Funding InformationUSDA–NIFA #2014–67017–21760, LSU AgCenter and Ingredion Incorporated.

Phenolic profile and fermentation patterns of different commercial gluten-free pasta during in vitro large intestine fermentation

The fate of phenolic compounds, along with short-chain fatty acids (SCFAs) production kinetics, was evaluated on six different commercial gluten-free (GF) pasta samples varying in ingredient compositions, focussing on the in vitro faecal fermentation after the gastrointestinal digestion. A general reduction of both total phenolics and reducing power was observed in all samples, together with a substantial change in phenolic profile over 24h of faecal fermentation, with differences among GF pasta samples. Flavonoids, hydroxycinnamics and lignans degraded over time, with a concurrent increase in low-molecular-weight phenolic acids (hydroxybenzoic acids), alkylphenols, hydroxybenzoketones and tyrosols. Interestingly, discriminant analysis also identified several alkyl derivatives of resorcinol as markers of the changes in phenolic profile during in vitro fermentation. Furthermore, degradation pathways of phenolics by intestinal microbiota have been proposed. Considering the total SCFAs and butyrate production during the in vitro fermentation, different fermentation kinetics were observed among GF pasta post-hydrolysis residues.

Potato powders prepared by successive cooking-process depending on resistant starch content affect the intestinal fermentation in rats.

The effects of resistant starch (RS) in dry potato powders prepared by various processes on intestinal fermentation in rats were assessed. Rats were fed raw potato powder (RP), blanched potato powder (BP), steamed potato powder (SP), or drum-dried potato powder (DP) for 4 weeks. The cecal RS content was significantly higher in the RP group than in the control diet (CN) group and other dry potato powder groups. Cecum pH was significantly lower in the RP group compared to the CN group, and was also significantly lower than that in the SP, BP, and DP groups. Lactic acid bacteria levels in the RP group were significantly higher than those in the CN group, and levels in the SP group also increased relative to the control group. Lactobacillus levels in the RP group were higher than in the CN and other dry potato powder groups. Cecal short-chain fatty acid (SCFA) concentrations in the RP group followed by the SP group exhibited significantly higher levels relative to the control levels. Dry potato powders containing RS produced during the cooking process may represent a useful food material that increases intestinal concentrations of SCFA and enhances the growth of certain lactic acid bacteria.

Flaxseed meal and oat hulls supplementation modulates growth performance, blood lipids, intestinal fermentation, bile acids, and neutral sterols in growing pigs fed corn–soybean meal–based diets

Flaxseed meal and oat hulls supplementation modulates growth performance, blood lipids, intestinal fermentation, bile acids, and neutral sterols in growing pigs fed corn–soybean meal–based diets

Dietary supplementation with tributyrin prevented weaned pigs from growth retardation and lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation

Dietary supplementation with tributyrin prevented weaned pigs from growth retardation and lethal infection via modulation of inflammatory cytokines production, ileal expression, and intestinal acetate fermentation