Increased Digesta Viscosity Research Articles

Increasing digesta viscosity altered nutrient transporter gene expression and decreased nutrient utilisation in Eimeria-challenged birds

ABSTRACT 1. Two experiments were conducted, the first was to investigate the effect of increasing digesta viscosity by dietary carboxymethyl cellulose (CMC) on the growth performance and intestinal morphology and characteristics of healthy birds. The second experiment evaluated the impact of increased digesta viscosity in birds during an Eimeria spp. challenge. 2. In experiment 1, a corn-soybean meal-based basal diet was supplemented with 0, 10 or 20 g/kg CMC at the expense of cornstarch and offered to seven birds in each of eight replicate cages per diet from d 8 to 22 post hatching. 3. Increasing digesta viscosity due to dietary CMC linearly reduced (p < 0.05) body weight (BW) gain and the apparent ileal digestibility of nutrients. The relative lengths of the duodenum, jejunum and ileum linearly increased (p < 0.01) with dietary CMC inclusion. 4. In experiment 2, on d 14, 256 broiler chickens were randomly assigned to eight replicate cages in a 2 × 2 factorial arrangement of treatments with two CMC concentrations (0 or 10 g CMC/kg of diet), with or without an Eimeria challenge. On d 15, birds in the challenge groups were orally gavaged with a 1 ml solution containing 25,000, 25,000 or 125,000 oocysts of E. maxima, E. tenella and E. acervulina; or 1% PBS, respectively. 5. Increasing digesta viscosity in Eimeria-challenged birds decreased the total tract digestibility of dry matter and gross energy (p < 0.05). The ileal gene expression of glucose transporters was upregulated (p < 0.05) in challenged birds that received the CMC-supplemented diet. 6. In summary, increased digesta viscosity induced changes in the expression of nutrient transporter genes and decreased nutrient utilisation in Eimeria-challenged birds.

Impact of long-term feeding a high level of Spirulina combined with enzymes on growth performance, carcass traits and meat quality in broiler chickens.

This study evaluates the effect of prolonged feeding with a high inclusion level of Spirulina, combined with peptidases, on broiler chicken's growth performance, digesta viscosity, carcass attributes and meat quality. The experiment involved 120 male broilers divided into 40 battery brooders, each housing 3 birds. Post 7-day acclimatisation with a corn and soybean-based diet, the birds were provided with one of four diets: a corn and soybean meal-based diet (CON), a mix incorporating 15% Spirulina (SP), a Spirulina-rich mix supplemented with 0.025% of commercial VemoZyme® P (SPV), or a Spirulina-rich mix supplemented with 0.10% of porcine pancreatin (SPP). The CON group had higher body weight and weight gain (p < 0.001) and a lower feed conversion ratio (p < 0.001) from day 7-21, compared to the Spirulina-fed groups. Spirulina-fed chickens significantly increased ileum viscosity (p < 0.05). Spirulina also elevated the weight (p < 0.05) of the duodenum and the length (p < 0.001) of the entire gastrointestinal tract compared to CON. Breast and thigh muscles from Spirulina-fed broilers displayed higher values of yellowness (b*) (p < 0.001), pigments (p < 0.05), and n-3 PUFA (p < 0.01), while n-6/n-3 ratio (p < 0.001) and α-tocopherol (p < 0.001) decreased relative to the CON. In conclusion, the introduction of a high level of Spirulina into broiler diets for an extended duration, has the potential to diminish birds' growth performance, possibly due to increased digesta viscosity. However, it does enhance the nutritional quality of the meat.

High- or low-fibre diet, meal size and frequency: Effect on ileal and total tract digestibility and mean retention time in growing pigs

This study aimed to determine the effect of the size and frequency of meals and diet type (high- or low-fibre) on fibre degradation and retention time of digesta in growing pigs. Pigs (n = 6) were fitted with a T-cannula, and each received all treatments following a 2 × 3 factorial arrangement in a 6 × 6 Latin square experimental design. The diets were either corn-soybean meal-based diet with low fibre (LowFibre) or wheat-barley based diet with high fibre (HighFibre) and distributed differently: 2 meals per day that met 3 times the maintenance energy requirement (2M), the same amount of feed in 8 meals (8M), and 8 meals per day that met 5 times the requirements (8M+). A diet type × meal interaction was observed for mean retention time (MRT) of the solid and liquid phase of digesta where MRT in LowFibre diet was higher in 2M compared to 8M and 8M+ while in HighFibre only 8M had lower MRT than 2M and 8M+ (Solid phase, P = 0.023, Liquid phase, P = 0.097). Ileum digesta from the LowFibre diet was less viscous than ileum digesta from HighFibre diet (P = 0.028) regardless of the meal distribution. Concentrations of the indigestible markers in the ileal digesta (TiO2 and YbCl3) increased faster in the LowFibre compared to the HighFiber diet, and marker concentrations were more constant in the 2M than the 8M and 8M+ treatments (P < 0.05). Coefficient of apparent ileal digestibility (CAID) of dry matter, energy, crude protein, total non-starch polysaccharides (NSP) and insoluble NSP was higher in the HighFibre diet than the LowFibre diet, while opposed results were observed for apparent total tract digestibility (P < 0.05). No effect of meal type was observed on CAID. Blood glucose levels were stable throughout the day for 8M and 8M+ while blood glucose for 2M was decreased between two meals (meal × time effect, P = 0.035). Larger meals in 2M-LowFibre, 2M-HighFibre and 8M+HighFibre can therefore explain longer MRT potentially due to decreased motility and slower gastric emptying. In conclusion, feeding pigs with an increased number of meals per day allows a continuous flow of digesta, stabilized blood glucose and increased digestibility. Ingestion of a high-fibre diet causes increased digesta viscosity. The type of diet had more impact on digestibility and transit time than the meal size and frequency.

PSVI-17 Digestawell XG Improves Piglet Performance When Dietary Net Energy Content is Decreased

Abstract Plant based dietary ingredients contain non-starch polysaccharides (NSP). Both soluble and insoluble NSP may limit intestinal absorption and digestion of dietary nutrients along the intestinal tract of monogastric animals. Increased digesta viscosity also occurs, which results in satiety and potential health issues. DIGESTAWell XG (Probiotech International Inc.), a commercially available enzyme-based feed additive that contains increased endo-1,4-β-xylanase and endo-1,3(4)-β-glucanase activity, hydrolyzes NSP resulting in increased nutrient availability and digestibility. Therefore, it was hypothesized that nursery pigs consuming low net energy (NE) diets with DIGESTAWell XG will demonstrate similar growth performance as nursery pigs consuming greater NE diets. A 47-day trial was conducted with 21-day old nursery pigs (6.0 kg) allocated to three groups: control (CON), low energy (-56 kcal/kg feed; LE), and low energy + enzyme (LE+E). All groups had 13 pens of 28 pigs (n = 364), and received wheat and corn mix based diets that had a similar NSP content (11.4%). CON diets had greater NE (2,456 kcal/kg feed) relative to the LE and LE+E groups (2400 kcal/kg feed). The diet of the LE+E group was supplemented with DIGESTAWell XG at 0.22kg/Ton of feed. For each pen the daily feed intake, weekly weight, diarrhea index and mortality were recorded. Data were analyzed by an ANOVA model (Statistix 8.0; Analytical Software, FL) including treatment and pen as fixed and random effects, respectively, and a Chi-square test for pairwise differences. Compared with both CON and LE, LE+E increased (P &amp;lt; 0.05) average daily gain (ADG) and average daily feed intake (ADFI) during weeks 4 to 7 and weeks 1 to 7, and significantly increased final weight (Table 1). During weeks 1 to 3, ADG and ADFI did not differ between CON and LE+E groups, and the LE+E group was significantly greater than LE. Over the entire period, LE impacted (P &amp;lt; 0.05) negatively the feed conversion ratio (FCR) compared with CON, however, during weeks 4-7 the LE+E had similar FCR compared with CON (P &amp;gt; 0.05). No significant effects were observed on mortality or diarrhea index. In conclusion, DIGESTAWell XG improves piglet performance when dietary NE content is decreased which may offer some formulation flexibility.

SUPPLEMENTATION OF NSPASE IN FULL-FAT SOYBEAN-BASED DIETS IN BROILER CHICKEN

The present study aimed to assess the impact of incorporating commercially available non-starch polysaccharide enzyme (NSPase) in soybean meal (SBM) and full-fat soybean-based diets on broiler bird development, nutritional digestibility, and gut health. Feed costs account for a significant portion, up to 70%, of overall production expenses in poultry businesses. Broiler diets predominantly consist of cereal grains, which contain varying levels of non-starch polysaccharides (NSPs), a fibrous component. The presence of NSPs in broiler diets hampers overall performance by reducing nutrient absorption due to increased digesta viscosity, thereby decreasing feed efficiency. It is estimated that 400-450 kcal/kg of feed remains unmetabolized in broilers fed a standard corn-soy diet. Exogenous enzymes function by making previously indigestible substances accessible for digestion by endogenous enzymes. NSPase enzyme has the potential to enhance digestion by reducing viscosity and releasing energy through the breakdown of undigested feed components.

PSXIII-11 Avemix XG 10 Improves Piglet Performance When Dietary net Energy Content is Decreased

Abstract Plant-based dietary ingredients contain non-starch polysaccharides (NSP) fibers. Both soluble and insoluble NSP fibers are anti-nutritional factors for monogastrics that limit intestinal absorption and digestion of dietary nutrients. Increased digesta viscosity also occurs, which results in satiety and potential health issues. AveMix XG 10, containing high endo-1,4-β-xylanase and endo-1,3(4)-β-glucanase activity, hydrolyzes NSP fibers resulting in increased nutrient availability and digestibility. Therefore, it was hypothesized that AveMix XG 10 enables gain of some extra net energy (NE) content from piglet diets, optimizing the cost of live-weight growth. A 47-day trial was conducted with 3-week old weaned piglets (6.0 kg) allocated to three groups: control (CON), low energy (-56 kcal/kg feed; LE), and low energy + enzyme (LE+E). All groups had 13 pens of 28 pigs (n=364) and received wheat and corn mix based diets that had a similar NSP fiber content (11.4 %). Overall, CON diets had greater NE (2,456 kcal/kg feed) relative to the LE and LE+E groups (2,400 kcal/kg feed). The diet of the LE+E group was supplemented with AveMix XG 10 (Palital Feed Additives B.V.) at 100 g/T. For each pen the daily feed intake, weekly weight, diarrhea index and mortality were recorded. Compared with both CON and LE, LE+E significantly increased average daily gain (ADG) and average daily feed intake (ADFI) during weeks 4-7 and overall, and also significantly increased final weight (Table 1). During weeks 1-3, ADG and ADFI did not differ between CON and LE+E groups, and the LE+E group was significantly greater than LE. Overall, LE detrimentally increased the feed conversion ratio (FCR) compared with CON; however, during weeks 4-7 the LE+E had similar FCR compared with CON. No significant effects were observed on mortality or diarrhea index. In conclusion, AveMix XG 10 improved piglet performance when dietary NE content is decreased.

Effect of dietary Spirulina (Arthrospira platensis) on the intestinal function of post-weaned piglet: An approach combining proteomics, metabolomics and histological studies

The effect of dietary Spirulina (Arthrospira platensis) and CAZyme supplementation was assessed on the gut of weaned piglets, using an integrated NMR-metabolomics approach combined with Tandem Mass Tag labelled proteomics. Thirty weaned male piglets were assigned to one of the three following diets (n = 10): cereal and soybean meal basal diet (Control), basal diet with 10% Spirulina inclusion (SP) and SP diet supplemented with 0.01% lysozyme (SP + L). The experiment lasted 4 weeks and, upon slaughter, small intestine samples were collected for histological, metabolomic and proteomic analysis. No significant differences were found for the histology and metabolomics analysis between the three experimental groups. Lactate, glutamate, glycine and myo-inositol were the most abundant metabolites. Proteomics results showed 1502 proteins identified in the intestine tissue. A total of 23, 78, 27 differentially abundant proteins were detected respectively for the SP vs. Control, SP + L vs. Control and SP + L vs. SP comparisons. The incorporation of Spirulina and supplementation of lysozyme in the piglet's diets is associated to intestinal proteomic changes. These include increased protein synthesis and abundance of contractile apparatus proteins, related with increased nutrient availability, which has beneficial (increased glucose uptake) and detrimental (increased digesta viscosity) metabolic effects. SignificanceThe use of conventional feedstuffs becomes increasingly prohibitive due to its environmental toll. To increase the sustainability of the livestock sector, novel feedstuffs such as microalgae need to be considered. However, its recalcitrant cell wall has antinutritional effects that can inhibit high dietary inclusion levels. The supplementation with CAZymes is a possible solution to this issue. The small intestine is a central piece in monogastric digestion and of particular importance for the weaned piglet. Studying the effect of dietary Spirulina and CAZyme supplementation on its histomorphology, metabolome and proteome allows studying relevant physiological adaptations to these diets.

Evolutions of rheology, microstructure and starch hydrolysis of pumpkin‐enriched bread during simulated gastrointestinal digestion

AbstractIn this study, the influences of pumpkin flour additions to breadmaking on evolutions of microstructure, rheology and starch hydrolysis during simulated gastrointestinal digestion were investigated. Compared to white bread (PB0), the bread supplemented with 20% pumpkin flour (PB20) showed more continuous and fibrous gel network structure with most starch granules encapsulated in the network throughout the in vitro digestion. Due to the dilution of digestive fluids and enzymatic hydrolysis, the digesta moduli and viscosity remarkably decreased as time progressed, but PB20 presented significantly higher rheology compared to PB0 in each digestion phase. At the end of intestinal phase, the in vitro starch digestibility was 69.9% for PB0, significantly higher than that for PB20 (55.4%). This is presumably attributed to the abundant dietary fibre in pumpkin flour, contributing to the increased digesta viscosity and the formation of more compact and stable gel networks that would hinder the contact of starch granules with α‐amylase. In addition, the pumpkin‐added breads gave satisfactory results in terms of sensory acceptability. This study has suggested promising potential of incorporating pumpkin flour in the production of functional bakery products with reduced starch digestibility while maintaining good sensory characteristics.

Evidence of intermolecular associations of β-glucan and high-molar mass xylan in a hot water extract of raw oat groat

High molar mass (HM) β-glucan present in oat products can reduce the risk of diet-related diseases, mainly owing to significantly increased digesta viscosity in human small intestine. To verify a research hypothesis that arabinoxylan (AX) present in oat water extract is associated with HM-β-glucan and thus may influence its functionality, multi-detection HPSEC coupled with enzymatic hydrolysis, sugar and 1H NMR analyses were performed. Isolated cell wall polysaccharide fraction comprised branched AX (arabinose-to-xylose ratio, Ara/Xyl ~ 0.8) and arabinogalactan-protein (AG-P). Nevertheless, it contained (10%) unbranched HM-xylan subfraction (weight-average molar mass, Mw ~ 3153 kg/mol), which was aggregated with β-glucan (Mw ~ 1029–1589 kg/mol) through its HM cellulose-like region. Of the two low molar mass-AXs (LM-AXs) isolated, the first having C(O)-3-monosubstituted and C(O)-2,3-disubstituted β-d-xylopyranosyl residues was covalently interlinked to HM-xylan. The second highly feruloylated, containing C(O)-3- and C(O)-2-monosubstituted units, was tightly bound to AG-P with terminal and 5-linked α-L-arabinofuranosyl residues, and non-covalently associated with LM-β-glucan subfraction.

Performance indicators and gastrointestinal response of rabbits to dietary soybean meal replacement with silkworm pupae and mealworm larvae meals

ABSTRACT The objective of this study was to determine the effects of silkworm pupae meal (SPM) and mealworm larvae meal (MLM) on the production results and function of the digestive system in rabbits. Thirty male New Zealand White growing rabbits were divided into three feeding groups: control (C) (10% soybean meal [SBM] in the diet), group SPM (5% SBM and 4% SPM) and group MLM (5% SBM and 4% MLM). Compared with group C, rabbits of groups SPM and MLM, were characterised by higher final body weight and daily body weight gains. They were also found to have better apparent total tract digestibility (ATTD) of ether extract, and acid detergent fibre (ADF) and acid detergent lignin (ADL). Increased digesta viscosity was observed in these rabbits, as well as reduced extracellular activity of bacterial α-glucosidase, β-glucosidase, α-arabinofuranosidase and β-xylosidase in the caecal digesta. Similar differences between groups were also noted for the intracellular activity of β-glucuronidase, total activity of β-xylosidase and α-glucosidase. The SPM and MLM treatments contributed to an increase in the extracellular and total activity of N-acetyl-β-D-glucosaminidase (NAGase) in the caecal digesta. The SPM and MLM treatments were characterised by increased extracellular/total activity of colonic bacterial NAGase as well as increased release rates of NAGase and β-cellobiosidase, compared with group C. The rabbits fed the MLM diet had the lowest caecal concentrations of acetic acid, propionic acid, and total short chain fatty acids (SCFA). The proportion of butyric acid in the caecal SCFA profile was significantly lower in group MLM than in group C. The SPM treatment reduced the colonic concentration of iso-valeric acid. Group C had the highest colonic SCFA pool. It can be concluded that an inclusion of 4% SPM and 4% MLM in rabbit diets improved their production results, as well as beneficially increased the ATTD of fat, ADF and ADL without compromising the ATTD of other nutrients and energy. Although both dietary insect-derived products caused a mobilisation of microbiota to utilise of chitin (see NAGase activity), they stifled the metabolism of large intestinal microbiota, as manifested by decreased enzyme activity and lower SCFA concentrations.

Effects of African Bentonite on Feed Mycotoxigenic Fungi and Growth of African Catfish Clarias gariepinus

Feed and feed ingredients in the tropics are prone to attacks of mycotoxigenic fungi (myco-fungi) infestation during storage or from the field. The heat applied in feed production destroys only the myco-fungi leaving mycotoxins that eventually end up in the fish. Mycotoxins have negative effects on the growth of fish. It is plausible to reduce or totally eliminate the mycotoxins and myco-fungi by the inclusion of special African bentonite supplement called “Uro’. Five iso nitrogenous and iso energetic feed were made with soybean meal of 12% moisture stored at relative humidity of 78% and temperature 29.45±0.87oC for 30 days. The feed was labelled as F1 to F5 and varied in inclusion levels of bentonite supplement as follows, F1, 34%, F2, 25%, F3, 15%, F4, 5% and F5, 0%. The protein supplement and basal ingredients in the diets were same. Feed ingredients were weighed, mixed, conditioned and pelleted. The feed was dried at 40oC for 24 hours and subjected to mycological analysis. African catfish fingerlings of average weight 6.5±0.36 g were stocked at 15 fish per three replicate aquaria per feed type. Fish were fed to satiation twice daily for 140 days. The catfish fed with F1(35% bentonite) had the best food conversion ratio, 1.63±0.15, highest SGR 5.7±0.05% day1 , weight gain 45.7±3.65g, protein efficiency ratio 1.19±0.10 and highest gut weight 3.46±0.45g. All growth and nutritional parameters were increasing with increasing inclusion of bentonite. Mycological analyses showed that three myco-fungi, namely Aspergilus flavus, Mucor mucedo and Cladosporium cladosporioides were prevalent in the feed. However, feed 1 to feed 3, were completely free from myco-fungi, while feed 4 had traces of M. mucedo and C. Cladosporioides but all myco-fungi were prevalent in F5. African bentonite is calcinated and sequestered feed ANF, myco-fungi and mycotoxins. Bentonite increased digesta viscosity which enabled better digestion of feed, lower FCR, enhanced alkaline intestine for protein and fatty acid absorption. Bentonite increased catfish total glycerides and cholesterol but reduced AST and ALT of the catfish.

Effect of particle size of insoluble fibre on growth performance, apparent ileal digestibility and caecal microbial population in broiler chickens fed barley-containing diets

ABSTRACT 1. This study was conducted to investigate the effect of particle size of insoluble fibre on growth performance, apparent ileal digestibility (AID) and caecal microbial population in broiler chickens fed barley-containing diets. 2. The dietary treatments included: a barley-based diet (control, CTL) or test diets which contained high-fibre ingredients, either sunflower hulls (SFH), sugarcane bagasse (SB) or wheat bran (WB) ground through a 1.0 (fine) or 3.0 mm (coarse) screen that were added to the control diet at 30 g/kg. 3. For the entire experimental period, insoluble fibre inclusion improved ADG (P < 0.05) and FCR (P < 0.05) compared to the CTL group. Broilers fed SFH had higher (P < 0.05) ADG and better (P < 0.05) FCR than broilers fed SB. 4. Fibre inclusion increased the relative weight of breast and thigh and decreased relative weight of liver compared to the CTL group, but coarse grinding of the SB decreased relative weight of abdominal fat (P < 0.05). 5. The digestibility of nutrients increased with dietary inclusion of insoluble fibre compared to the CTL group. Coarse grinding of SFH increased AID of crude protein compared to the coarse grinding of WB or SB. Fine grinding of various types of fibre improved the AID of fat (as ether extract) and organic matter (P < 0.05). 6. Fine grinding of the WB decreased caecal populations of E. coli. The inclusion of SFH increased caecal populations of Lactobacillus spp. (P < 0.05). Coarse grinding of various types of fibre decreased the caecal population of coliforms (P < 0.05). 7. The inclusion of WB increased digesta viscosity in the ileum compared to samples from the SB and SFH groups (P < 0.05). Coarse grinding of various types of fibre decreased the digesta viscosity in the ileum (P < 0.05). 8. Overall, the data showed that dietary inclusion of insoluble fibre improved growth performance, increased AID of nutrients and decreased ileal viscosity in the birds fed diets containing barley.

Retention of primary bile salts by dry beans (Phaseolus vulgaris L.) during in vitro digestion: Role of bean components and effect of food processing

The positive effect of common beans on reducing blood cholesterol levels has been linked to their ability to sequester bile salts (BS) and prevent their recycling. We have examined the preferences of major bean components (soluble/insoluble fiber, starch and proteins) to retain BS, and the role played by the bean matrix. Additionally, the kinetics of BS-release were evaluated in bean flours generated by a combination of hydrothermal or high-hydrostatic pressure (HHP), and mechanical treatments. An in vitro digestion model combined with dialysis was used to evaluate separately the retention of primary individual BS. Soluble fiber retained a significant proportion of BS mainly due to an increased digesta viscosity; however, the protein fraction exhibited the greatest BS retention without affecting viscosity. The thermal properties of proteins and starch were more significantly affected in presence of tauro-chenodeoxycholate, which correlated to the affinity of both fractions to retain more hydrophobic BS during digestion. Glyco-chenodeoxycholate and tauro-cholate were the most and least effectively retained BS by bean flours, respectively. Neither of the processing treatments had an impact on the binding preferences of bean flours to the primary BS; however, the largest BS retention was caused by HHP at 600 MPa. Bean materials preferentially delayed the release of chenodeoxycholate BS, which is probably related to BS micelle formation. These findings demonstrate that a combination of viscosity, molecular and compositional factors is triggering the BS-retention capacity of beans, and indicate the importance of evaluating contribution of individual bean components and as whole system.

The effect of viscous soluble dietary fiber on nutrient digestion and metabolic responses Ⅰ: In vitro digestion process

The consumption of viscous soluble dietary fibers (VSDF) as thickening agents for beverages and fluid foods has increased with their ability to modulate postprandial glycaemic response due to increasing digesta viscosity. The present study was designed to establish appropriate VSDF viscosity that can beneficially modulate nutrient digestion and attenuate glucose release and absorption. The effects of xanthan (XG), guar gum (GG) and locust bean gum (LBG) on the digestibility of starch and protein in beverages with initial low viscosity (300 mPa s, 30 s−1) and high viscosity (1500 mPa s, 30 s−1) were investigated using the proposed Infogest simulated digestion model. Moreover, the effects of dilution, physiological pH and enzymatic activities on viscosity decrease of three gums during digestion were evaluated. The results showed that at the end of intestinal digestion, XG showed the highest viscosity at low and high viscosity followed by GG and LBG, respectively. During the intestinal digestion process, three gums have little effects on protein and starch digestion at low viscosity. However, all the gums significantly reduced nutrient digestion at higher viscosity, and XG exhibited the best performance in reducing the amount of glucose and free amino acid released. The digestion rates of protein and starch showed a linear relationship with the viscosity of the system. Similarly, the amount of glucose diffused as a function of time was most significantly (p < 0.05) decreased by XG followed by GG. At low and high initial viscosities, dilution of the gastrointestinal contents was the most important source of viscosity reduction for all gums, and XG was the most resistant to dilution and recorded the least viscosity drop. These observations suggested that XG with high viscosity may serve as a useful food ingredient to attenuate postprandial glucose spikes in human.

Characterization of lipid emulsions during in vitro digestion in the presence of three types of nanocellulose

HypothesisNanocellulose (NC) has been a topic of significant interest due to its multiple applications, including that as a potential food ingredient. Due to the viscous property of NC and its potential use as emulsion stabilizers, presence of NC in food may affect properties and digestion of lipid emulsions systems. In this study, the behavior of three types of nanocellulose and its influence on lipid emulsions during digestion were investigated. ExperimentsThe changes in physicochemical characteristics (including particle size, microstructure, viscosity, and zeta potential) of the emulsions as well as the amount of free fatty acid released were studied and compared among the addition of different types/concentrations of fiber as well as digestion phases. FindingsThe colloidal stability of three types of NC differed during each digestion phase. Specifically, cellulose nanocrystals (CNC) formed hydrogel networks during the gastric phase, resulting in increased digesta viscosity. Cellulose nano-fibrils (CNF) were stable and had no morphological changes during digestion. TEMPO-oxidized cellulose nano-fibrils (TEMPO-CNF) de-swelled and showed aggregation at the gastric phase. Results showed that all three types of nanocellulose at high concentrations (1% CNF, 0.25–0.36% TEMPO-CNF or 2–3% CNC) delayed initial in vitro digestion of emulsions, though the final lipolysis extent was nearly the same amongst all (47–55%).

Larger particle size of oat bran inhibits degradation and lowers extractability of β-glucan in sourdough bread – Potential implications for cholesterol-lowering properties in vivo

Increased digesta viscosity is considered the mechanism underlying the cholesterol-lowering effect of oat β-glucan. Viscosity is mainly related to the molecular weight and concentration of solubilized β-glucan in the digesta and these should therefore be maintained at sufficiently high levels. Bread that includes oat bran is a potential source of β-glucan, but the baking process leads to degradation by β-glucanases present in the flours.In the current study, we investigated the effect of fermentation time as well as of particle size and content of oat bran in breads on the molecular weight, solubility and extract viscosity of β-glucan. Furthermore, we estimated the potential of the breads to have a cholesterol-lowering effect by comparison of molecular weight, solubility and extract viscosity of β-glucan with those of products known to have an effect in vivo.Longer fermentation time and smaller particles were found to lead to lower molecular weight of β-glucan. However, smaller particles also increased its extractability, leading to an overall increase in extract viscosities compared with coarse particles. Bread with the inclusion of 30% finely-milled, but not coarse oat bran was found to induce extract viscosity with the potential of producing a cholesterol-lowering effect despite more degraded β-glucan.

The effect of poultry litter biochar on pellet quality, one to 21 d broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility

Feeding poultry litter biochar (PLB), a product resulting from litter gasification, could decrease diet cost, maintain broiler growth performance, and decrease land application of manure. Past research observed improved pellet quality and mineral availability with dietary inclusions of 6 to 7% PLB; however, broiler performance was decreased, likely due from toxic-heavy-metal content (e.g., 99 ppm arsenic) and increased digesta viscosity of the particular PLB. The objective of the current study was to assess lower dietary inclusions of PLB, with decreased toxic-heavy-metal content, on descriptive feed manufacture, broiler performance, digesta viscosity, bone mineralization, and apparent ileal amino acid digestibility (AIAAD). Treatments were arranged as a Diet Formulation x Phytase Addition factorial in a randomized complete block design with 8 replications per treatment. Four dietary formulations were produced: positive control (PC) with 0.45% non phytate phosphorus (nPP), negative control with 0.23% nPP, and 2 or 4% PLB with 0.45% nPP. Phytase was either included at 9,500 ftu/kg or withheld. There were 8 treatments total. Contrasts comparing PC and 2 or 4% PLB also were conducted. Diets were pelleted and crumbled prior to feeding. Positive and negative control formulations and phytase addition affected bird performance as expected. Birds fed 2% PLB had increased FCR and birds fed 4% PLB had decreased LWG when compared to PC (P < 0.05). However, these performance deficiencies were corrected with phytase inclusion. Birds fed diets with PLB had similar tibia measures compared to the PC. No significant main effects, interactions, or contrast comparisons were observed for viscosity data. The incorporation of PLB into formulations without phytase increased diet AIAAD of some amino acids relative to the corresponding PC (P < 0.05). A lower toxic-heavy-metal PLB product (e.g., 22 ppm arsenic) provided available minerals and amino acids to diets, but performance similar to PC necessitated the addition of phytase.

In vitro digestion of pectin- and mango-enriched diets using a dynamic rat stomach-duodenum model

In this study we investigated the in vitro digestive behaviors of starch-based diets enriched with soluble fiber (pectin) and fruit powder (mango) varying with dry matter contents using a dynamic rat stomach and duodenum model. The changes in pH with respect to digestion time, gastric emptying, starch and protein hydrolysis as well as rheological and microstructural properties of the gastric and duodenal digesta were investigated. The effects of porcine gastric mucin on digestion were studied as well. The results showed that gastric digestion and emptying rate were decreased with increasing dry matter content of the diets. Both the dynamic and steady shear viscosity of the duodenal digesta was lower than the gastric digesta due to hydrolysis of starch and protein as well as dilution by added digestive juice. With the same dry matter content (20.35%), the rates of gastric emptying as well as starch and protein hydrolysis were higher in the control and mango diets compared to the pectin diet, illustrating the complex relationships among rheology, soluble dietary fiber and digestion. The addition of gastric mucin could delay the rates of gastric digestion and emptying by increasing digesta viscosity. The study emulates the complexity of heterogeneous diets during simulated gastric and duodenal digestion and suggests that the viscosity generated by either addition of mucin on the diet or naturally exerted by e.g. pectin could be the rate limiting factor for both gastric emptying and hydrolysis of starch and proteins.

Re-evaluation of the mechanisms of dietary fibre and implications for macronutrient bioaccessibility, digestion and postprandial metabolism.

The positive effects of dietary fibre on health are now widely recognised; however, our understanding of the mechanisms involved in producing such benefits remains unclear. There are even uncertainties about how dietary fibre in plant foods should be defined and analysed. This review attempts to clarify the confusion regarding the mechanisms of action of dietary fibre and deals with current knowledge on the wide variety of dietary fibre materials, comprising mainly of NSP that are not digested by enzymes of the gastrointestinal (GI) tract. These non-digestible materials range from intact cell walls of plant tissues to individual polysaccharide solutions often used in mechanistic studies. We discuss how the structure and properties of fibre are affected during food processing and how this can impact on nutrient digestibility. Dietary fibre can have multiple effects on GI function, including GI transit time and increased digesta viscosity, thereby affecting flow and mixing behaviour. Moreover, cell wall encapsulation influences macronutrient digestibility through limited access to digestive enzymes and/or substrate and product release. Moreover, encapsulation of starch can limit the extent of gelatinisation during hydrothermal processing of plant foods. Emphasis is placed on the effects of diverse forms of fibre on rates and extents of starch and lipid digestion, and how it is important that a better understanding of such interactions with respect to the physiology and biochemistry of digestion is needed. In conclusion, we point to areas of further investigation that are expected to contribute to realisation of the full potential of dietary fibre on health and well-being of humans.

The effects of pelleting and glucanase supplementation in hulled barley based diets on feed manufacture, broiler performance, and digesta viscosity

Feeding broilers barley-based diets requires special consideration primarily due to effects on increased digesta viscosity and decreased nutrient digestion. Pelleting and glucanase supplementation are commonly performed prior to feeding broilers barley-based diets; however, the interaction of these practices is complex. The objective of this study was to establish a comprehensive evaluation of glucanase efficacy including: degree of processing, activity postpelleting, broiler performance, and digesta viscosity. Treatments were arranged in a 5 (diet formulation) × 2 (processing) factorial in a randomized complete block design with 8 replications/treatment. The 5 diet formulations consisted of positive control (PC), negative control (NC), glucanase A (GA) 125 or 1,000 β-Glu-U/kg feed, and glucanase B (GB) 1,000 β-Glu-U/kg feed. The PC and NC diets differed in metabolizable energy by 150 kcal/kg and enzymes were added to NC formulations. Diets were either fed as unprocessed mash or ground pellets. Diet formulation × processing did not interact for feed intake (FI), FCR, or total tract viscosity (P > 0.05); however, a trend was observed for ending bird weight, demonstrating that for ground pellets, GA 1,000 β-Glu-U/kg feed was improved relative to NC and similar to PC (P = 0.0903). Benefits associated with GB were not of similar magnitude, perhaps in part due to a 50% decrease in activity postpelleting. In addition, GA benefits were not suggested for unprocessed mash. The main effect processing was significant (P < 0.0001) demonstrating that broilers fed ground pellets resulted in greater pen ending bird weight, FI, and bird live weight gain (LWG) compared to birds fed unprocessed mash diets. Evaluations of glucanase should go beyond in vitro activity and include live bird performance using feed that has undergone pelleting.