Dietary xylo‑oligosaccharides and arabinoxylans improved growth efficiency by reducing gut epithelial cell turnover in broiler chickens

Background One of the main roles of the intestinal mucosa is to protect against environmental hazards.Supple-mentation of xylo-oligosaccharides(XOS)is known to selectively stimulate the growth of beneficial intestinal bacteria and improve gut health and function in chickens.XOS may have an impact on the integrity of the intestinal epithelia where cell turnover is critical to maintain the compatibility between the digestive and barrier functions.The aim of the study was to evaluate the effect of XOS and an arabinoxylan-rich fraction(AXRF)supplementation on gut func-tion and epithelial integrity in broiler chickens.Methods A total of 128 broiler chickens(Ross 308)were assigned into one of two different dietary treatments for a period of 42 d:1)control diet consisting of a corn/soybean meal-based diet;or 2)a control diet supplemented with 0.5%XOS and 1%AXRF.Each treatment was randomly distributed across 8 pens(n=8)with 8 chickens each.Feed intake and body weight were recorded weekly.On d 42,one male chicken per pen was selected based on aver-age weight and euthanized,jejunum samples were collected for proteomics analysis.Results Dietary XOS/AXRF supplementation improved feed efficiency(P<0.05)from d 1 to 42 compared to the con-trol group.Proteomic analysis was used to understand the mechanism of improved efficiency uncovering 346 dif-ferentially abundant proteins(DAP)(Padj<0.00001)in supplemented chickens compared to the non-supplemented group.In the jejunum,the DAP translated into decreased ATP production indicating lower energy expenditure by the tissue(e.g.,inhibition of glycolysis and tricarboxylic acid cycle pathways).In addition,DAP were associated with decreased epithelial cell differentiation,and migration by reducing the actin polymerization pathway.Put-ting the two main pathways together,XOS/AXRF supplementation may decrease around 19%the energy required for the maintenance of the gastrointestinal tract.Conclusions Dietary XOS/AXRF supplementation improved growth efficiency by reducing epithelial cell migration and differentiation(hence,turnover),actin polymerization,and consequently energy requirement for maintenance of the jejunum of broiler chickens.

Effect of Added Arabinoxylans Isolated from Good and Poor Chapati Making Wheat Varieties on Rheological Properties of Dough and Chapati Making Quality

Arabinoxylans are the major non-starch polysaccharides in wheat and are reported to influence quality of bakery products. Arabinoxylans were isolated from good and poor chapati making varieties, added them at different levels (0.25 and 0.5 g/100g) to the same flour, interchanged with other varieties and determined the effect of arabinoxylans on rheological properties of dough and chapati making quality. Rheological properties were improved upon adding isolated arabinoxylans of good chapati making varieties to flours. Interestingly, addition of isolated arabinoxylans of good chapati making varieties to poor chapati making varieties had significantly improved the chapati quality. Sensory studies showed that chapatis prepared from flour added with arabinoxylans of good chapati varieties had soft texture and high overall quality scores. These changes are attributed to differences in their arabinose/xylose ratio. Thus, results indicated that addition of isolated arabinoxylans of good chapati making flour improved the chapati quality of poor chapati making flour.

Effect of arabinoxylo-oligosaccharides and arabinoxylans on net energy and nutrient utilization in broilers

Arabinoxylo-oligosaccharides(AXOS) are hydrolytic degradation products of arabinoxylans(AX) that can be fermented by the gut microbiota, thus potentially displaying prebiotic properties. This study examined the effects of AX and AXOS on net energy(NE) and nutrient utilization in broilers. Ross 308 broilers(n = 90, 30 birds per treatment) were fed wheat-soybean diets supplemented with pure AX, AXOS produced by exposing the AX to xylanase in vitro(AXOS), or AX with xylanase(AX + E) from d 10 to 21.Performance parameters were measured from d 10 to 21. On d 15, 10 birds per treatment were allocated to closed-circuit net energy chambers to assess the impact of AX and AXOS on dietary energy utilization,through assessment of both metabolisable energy(ME) and NE. Ileal and caecal digesta samples were collected on d 21 to determine the effect of AX and AXOS on ileal and total tract dry matter digestibility,ileal digestible energy, digesta pH, short chain fatty acids(SCFA) and microbiota concentration. Feed conversion ratio was numerically the lowest in birds fed the diet supplemented with AXOS, which is 1.26 compared to 1.37 and 1.30 for AX and AX + E, respectively. Ileal dry matter digestibility was higher in birds fed AXOS than those fed AX(P = 0.047). Ileal digestible energy and total tract dry matter digestibility were higher in birds fed AXOS than those fed AX or AX + E(P = 0.004 and P = 0.001,respectively). Birds fed AXOS had higher ME intake(P = 0.049) and nitrogen retention(P = 0.001) and a strong trend of higher NE(P = 0.056), NE intake(P = 0.057) and retained energy(P = 0.054) compared to those fed AX. Ileal total SCFA, lactic and formic acid concentrations were higher in birds fed AXOS than those fed AX(P = 0.011, P = 0.012 and P = 0.023, respectively). Birds fed AXOS or AX + E had higher caecal total SCFA, acetic, butyric and isovaleric acid concentrations compared to those fed AX(P = 0.001,P = 0.004, P = 0.016 and P = 0.008, respectively), and caecal propionic acid concentration was higher in birds fed AX + E than those fed AX(P = 0.050). Ileal and caecal microbiota concentrations were numerically higher and pH was lower in birds fed AXOS and AX + E than those fed AX. Results from this study indicate that feeding AXOS directly is more efficient than AXOS generation in the gastrointestinal tract, and suggest that AXOS has a potential to be an efficacious prebiotic in broiler diets.

Ferulic acid mediates prebiotic responses of cereal-derived arabinoxylans on host health

Dietary fiber is named as “the 7th nutrient” for humans, which is beneficial to improve intestinal healthand prevent metabolic disease of the host. Mechanisms of dietary fiber administration on improved hosthealth are mediated by short chain fatty acids (SCFA), which are reported to activate G protein-coupledreceptors (GPR) and suppress activity of histone deacetylase (HDAC) to down-regulate expression ofnuclear factor-к-gene binding (NF-кB) signaling. Arabinoxylan is fermented by gut microbiota to produceSCFA and improved microbial community composition, intestinal barrier functions and host health.Interestingly, the latest publications have observed that ferulic acid combined with the arabinose inarabinoxylans from various cereal grains can be released through gut microbial fermentation. Ferulic acidcan improve antioxidase activity and decrease reactive oxygen species (ROS) concentration by activatingthe signaling pathway of Kelch-like ECH-associated protein-1 and nuclear factor E2-related factor-2(Keap1-Nrf2). However, the role of ferulic acid in cooperation with SCFA produced from microbialfermentation of cereal-derived arabinoxylan to regulate the intestinal health and host metabolisms, hasbeen widely unclear. This review summarizes the potential mechanisms of ferulic acid from microbialfermentation of cereal-derived arabinoxylans on immunological functions and physiological metabolismsof the host. The evidence presented in the review indicates that dietary supplementation withcereal-derived arabinoxylans improves antioxidant capacity of intestinal epithelial cells due to theproduction of ferulic acid and SCFA from microbial fermentation. Ferulic acid can cooperate with SCFA toregulate intestinal integrity and immunological functions of the host. Peroxisome proliferator activatedreceptorg (PPARg) may play an important role in integrating ferulic acid and SCFA to regulate host healthand metabolism.

Debranching enzymes decomposed corn arabinoxylan into xylooligosaccharides and achieved prebiotic regulation of gut microbiota in broiler chickens

Background Corn arabinoxylan(AX)is a complicated and multibranched antinutritional factor,thereby proving the use of endo-xylanase(EX)to be marginally valid.This study focused on specific types of AX-degrading enzymes(ADEs)to exert the synergy of debranching enzymes and track the prebiotic potential of enzymatic hydrolysates.This study investigated the effects of ADEs on the growth performance,intestinal histomorphology,absorption functions,changes in polysaccharide components,fermentation,and gut microbiota of broiler chickens.Five hundred seventysix five-day-old Arbor Acres male broiler chickens were randomly allocated into eight treatments with six replicates each.Corn basal diets supplemented with or without enzymes were fed for a 21-day period,specifically including EX,its compatible use with arabinofuranosidase(EXA)or ferulic acid esterase(EXF),and compound groups with the above three enzymes(XAF).Results Specific ADEs stimulated the jejunal villus height and goblet cell number and evidently decreased the crypt depth(P<0.05),while the ratio of ileal villus height to crypt depth was significantly increased in EXF(P<0.05).Maltase activities of ileal mucosa in XAF groups were extremely enhanced(P<0.01),and EX boosted the activity of Na+-K+ATPase in the small intestine(P<0.01).The insoluble AX concentrations comparatively lessened,thereby notably raising the sundry xylooligosaccharide(XOS)yield in the ileal chyme(P<0.05),which was dominant in xylobiose and xylotriose.Improvements in the abundance and diversity of ileal microbial communities within the EXA,EXF,and XAF treatments were observed(P<0.05).Positive correlations between microbiota and XOS were revealed,with xylobiose and xylotriose being critical for ten beneficial bacteria(P<0.05).EXF increased the BWG and FCR of broiler chickens in this phase(P<0.05),which was attributed to the thriving networks modified by Lactobacillus.The intracecal contents of acetic acid,butyric acid,and propionic acid were greatly enhanced in most ADE groups,such as EXF(P<0.05).Conclusions Debranching enzymes appreciably targeted corn AX to release prebiotic XOS in the posterior ileum and facilitated intracaecal fermentation.It was beneficial for improving gut development,digestion and absorption and modulating the microflora to promote the early performance of broiler chickens.

Combinatorial Enzyme Approach to Convert Wheat Insoluble Arabinoxylan to Bioactive Oligosaccharides

Combinatorial enzyme technology was applied for the conversion of wheat insoluble arabinoxylan to oligosaccharide structural variants. The digestive products were fractionated by Bio-Gel P4 column and screened for bioactivity. One fraction pool was observed to exhibit antimicrobial property resulting in the suppression of cell growth of the test organism ATCC 8739 E. coli. It has a MIC value of 1.5% (w/v, 35°C, 20 hr) and could be useful as a new source of prebiotics or preservatives. The present results further confirm the science and useful application of combinatorial enzyme approach.

Release of Arabinose from Wheat Insoluble Arabinoxylan by the Action of α-L-Arabinofuranosidase in Synergism with Endo-Xylanases

Wheat arabinoxylan (water-insoluble fraction) contains ~36% arabinose which may include both singly or doubly substitutions at C2/C3 of the Xylp units. α-L-Arabinofuranosidses (ABFs) of two GH families were analyzed for their respective activities on the hydrolysis of Xylp-Araf. BaABF (GH43) produced twice the yield of arabinose residues from the heteroxylan compared to AnABF (GH51) under the same reaction conditions. Two endo-xylanases (of GH10 and 11) also showed differential hydrolytic activities on the Xylp chain, with the GH10 XYN-ATM double the amount of reducing sugar yield (as xylose equivalent) than using the GH11 XYN-M3. When the ABF and XYN were combined in optimial ratios, a synergistic increase of 73.8% in arabinose yield was observed.

Chicory(Cichorium intybus L.) and cereals differently affect gut development in broiler chickens and young pigs

Dietary fiber, resistant to host-mediated digestion in the small intestine due to lack of endogenous enzymes, impacts many facets of animal health and is associated with gut development especially in young monogastrics. Furthermore, it can be used as in-feed antibiotic alternative. Chicory （Cichorium intybus L.） forage with high content of pectin （uronic acids as building blocks） is a novel class of dietary fiber that is chemically different from cereal grains （with high content of arabinoxylans）. In the present study, we investigated effects of dietary inclusion of chicory forage on digestibility, gut morphology and microbiota in broilers and young pigs. In the chicken experiment, 160 1-d old broiler chicks were fed 3 nutritionally balanced diets for 30 d including a cereal-based diet and 2 diets with part of the cereals substituted with 60 and 120 g/k9 chicory forage （CF60 and CF120], whereas in the pig experiment, 18 seven-wk old Yorkshire pigs were fed 3 diets for 18 d including a cereal-based diet and 2 diets with 80 and 160 g/kg chicory forage inclusion （CF80 and CF160）. Our results showed that young pigs were capable to utilize chicory forage well with higher total tract apparent digestibility （TTAD） of all fiber fractions, particularly uronic acid, compared with the control （P 〈 0.01）. In contrast, a decreased TTAD of all fiber fractions was observed in chickens fed on diet CF120 （P 〈 0.05）. Moreover, diet induced changes in gut morphology were observed in the large intestine of chickens. The alteration of cecal mucosal thickness was further positively correlated with TTAD of non-starch polysaccharides （NSP） and its constituent sugars （P 〈 0.05）. In addition, in pigs, terminal restriction fragment length polymorphism （T-RFLP） analysis of intestinal microbiota revealed substantial dietary effects （cereal control diet vs. chicory forage inclusion） on the relative abundance of 2 dominant bacterial phylotypes （Prevotella sp. vs. Roseburia sp.） respectively （P 〈 0.05）. In conclusion, our data showed that chicory forage （Cichorium intybus L.）, a novel dietary fiber source in animal nutrition, have potential beneficial properties as fiber ingredient in diets for both pigs and chickens.

Genotypic and Environmental Variations of Arabinoxylan Content and Endoxylanase Activity in Barley Grains

Arabinoxylan （AX） content in barley grains is an important quality determinant when barley is used as raw material of malt or beer production. The cultivar and environmental variations of total arabinoxylan （TAX）, water extractable arabinoxylan （WEAX） and endoxylanase activity （EA） were investigated using eight barley cultivars growing at seven locations with diverse environmental conditions. The results showed that both barley cultivar and location significantly affected the TAX, WEAX and EA levels, but the variations of TAX content and EA were mainly attributed to cultivar, while the impact of location on WEAX content was greater than that of cultivar. Correlation analysis indicated that TAX was significantly correlated to WUAX.

Combinatorial Enzyme Approach for Production and Screening of Libraries of Feruloyl Oligosaccharides

Combinatorial chemistry involves the chemical or biological synthesis of diverse variation of the structures of a target molecule and the library is then screened for variants of desirable target properties. The approach has been a focus of research activity in drug discovery and biotechnology. This report is to demonstrate the application of enzyme technology using the concept of combinatorial chemistry as a novel approach for the bioconversion of plant fibers. Wheat insoluble fiber was subjected to combinatorial enzyme digestion to create structural variants of feruloyl oligosaccharides (FOS). Fractionation and screening resulted in the isolation of a fraction of bioactive FOS species showing antimicrobial activity. These results demonstrate the feasibility and usefulness of the combinatorial enzyme technique in the transformation of plant biomass to value-added products.

Identification of genes involved in the formation of soluble dietary fiber in winter rye grain and their expression in cultivars with different viscosities of wholemeal water extract

The grain of rye(Secale cereale L.) used for baking contains a large amount of non-starch polysaccharides,making it an excellent component of functional foods. But rye grain intended for alcohol production and forage use should have a reduced content of these polysaccharides. A comprehensive parameter that can predict the best field of application for winter rye grain is the viscosity of its wholemeal water extract.However, our understanding of the genetic background underlying this key trait and associated features of rye grain is poor. By analyzing six Russian winter rye cultivars, we identified the most contrasting forms and characterized the peculiarities of their water-soluble carbohydrates capable of influencing the viscosity of water extracts. Then, using phylogenetic and transcriptomic analyses, we identified in the rye genome many genes encoding putative glycosyltransferases and glycosylhydrolases responsible for the synthesis and degradation of arabinoxylans, mixed-linkage glucans, cellulose, and some other polysaccharides. We determined the dynamics of m RNA abundance for these genes at three stages of kernel development. Comparisons of gene expression levels in two contrasting cultivars revealed specific members of multigene families that may serve as promising targets for manipulating non-starch polysaccharide content in rye grain. High-viscosity cultivars were characterized by up-regulation of many glycosyltransferases involved in the biosynthesis of arabinoxylans and other cell-wall polysaccharides,whereas low-viscosity cultivars showed up-regulation of several genes encoding polysaccharidedegrading enzymes.

What Are the Characteristics of Arabinoxylan Gels?

Arabinoxylan gels are commonly characterized to determine the feasibility of utilizing them in numerous applications such as drug delivery systems. The general characteristics of numerous types of arabinoxylan gels as well as their susceptibility to degradation are discussed in this manuscript. There are two main types of arabinoxylan: water-extractable and alkali-extractable. The physicochemical characteristics of the arabinoxylan determine its extractability and gelling characteristics. Gels can be created from numerous types of arabinoxylan including wheat (Triticum aestivum L.) and maize (Zea mays L.). These gels can also be developed with the addition of protein and/or β-glucan, which results in modified mechanical properties of the gels. To create a sound gel, arabinoxylan must be cross-linked, which is often done through ferulic acid. When this takes place, the gel developed is thermo-irreversible, unsusceptible to pH and electrolyte interactions, and does not undergo syneresis during storage. Despite these strengths, arabinoxylan gels can be broken down by the enzymes produced by Bifidobacterium, which is present in the human large intestine. After further development and research on these gels, they could be utilized for many purposes.

Reduced-particle size wheat bran and endoxylanase supplementation in broiler feed affect arabinoxylan hydrolysis and fermentation with broiler age differently

Since the caecal microbiota of young broilers are not yet able to ferment the dietary fibre(DF)fraction of the feed to a large extent,increasing the accessibility of DF substrates along the gastrointestinal tract is crucial to benefit from the health stimulating metabolic end-products(e.g.butyric acid)generated upon microbial DF fermentation.Therefore,the present study aimed to evaluate the potential of reduced-particle size wheat bran(RPS-WB)and endoxylanases as feed additives to stimulate arabinoxylan(AX)hydrolysis and fermentation along the hindgut of young broilers.To this end,RPS-WB and endoxylanase supplementation were evaluated in a 2×2 factorial design using a total of 256 male 1-d-old chicks(Ross 308).Broilers were assigned to 4 dietary treatments:a basal wheat-based diet with(1)no feed additives(control,CTRL),(2)an endoxylanase(XYL;Econase XT 25 at 0.10 g/kg diet),(3)1%wheat bran with an average reduced particle size of 297μm(RPS-WB)and(4)an endoxylanase and 1%RPS-WB(RPS-WB+XYL).Each dietary treatment was replicated 8 times and on d 10 and 28,respectively,24 and 16 broilers per treatment group were euthanised to analyse AX degradation,short-chain fatty acid production and digesta viscosity in the ileum and caecum.Broilers receiving XYL in their diet showed increased AX solubilisation and fermentation at both d 10 and 28 compared to the CTRL group(P<0.05).Adding RPS-WB to the diet stimulated wheat AX utilisation by the primary AX degraders in the caecum at 10 d of age compared to the CTRL group,as observed by the high AX digestibility coefficient for the RPS-WB supplemented group at this young age(P<0.05).At 28 d,RPS-WB supplementation lowered body-weight gains but increased butyric acid concentrations compared to the XYL and CTRL group(P<0.05).Although no synergistic effect for RPS-WB+XYL broilers was observed for AX hydrolysis and fermentation,these findings suggest that both additives can raise a dual benefit to the broiler as a butyrogenic effect and improved AX fermentation along the ileum and caecum were observed throughout the broiler's life.

Major cereal carbohydrates in relation to intestinal health of monogastric animals:A review

Type,quality,and origin of cereals in diets of poultry and pigs could influence gut microbes and affect their diversity and function,thereby impacting the intestinal function of the monogastric animal.In this review,we focus on the major carbohydrates in cereals that interact directly with gut microbes and lead to the production of key metabolites such as short-chain fatty acids(SCFA),and discuss how cereal fiber impact intestinal health of poultry and pigs.An overview of how the cereals and cereals-derived carbohydrates such as beta-glucans,resistant starch,cellulose,and arabinoxylans could promote intestinal health and reduce the use of in-feed antibiotics in animal production are presented.The metabolic pathway utilized by microbes and the mechanism of action underlying the produced SCFA on intestinal health of monogastric animals is also discussed.

Impact of xylanases on gut microbiota of growing pigs fed corn-or wheat-based diets

This study investigated the effects of xylanase supplementations with cereal-based diets on nutrient digestibility and gut microbiota of growing pigs. A total of 96 individually penned pigs(initial BW = 22.7 ± 0.65 kg) were allotted to 12 treatments and subjected to a completely randomized block design experiment. Pigs in each treatment were fed an isocaloric wheat-based or corn-based diet with or without 1 of 5 types of xylanase supplements(XA, XB, XC, XD, XE). On d 42, all piglets were euthanized to obtain ileal and cecal digesta for microbial analysis, which involved high-throughput sequencing of the V1 - V3 regions of 16 S rRNA gene. Corn-and wheat-based diets differed(P < 0.05) in digestion characteristics. Dietary treatments affected the alpha-and beta-diversities of microbiota in the cecum but not in the ileum. The wheat-based diet increased(P < 0.05) alphadiversity and clustered separately(P < 0.05) compared with the corn-based diet. Wheat-based diet also promoted the relative abundance of genus(g.) Succinivibrio while corn-based diet promoted the proportion of family(f.) Veillonellaceae in the community. Among xylanases, only XC within the wheat-based diet altered(P < 0.05) the beta-diversity of the cecal microbiota compared with control. For each cereal-based diet and compared with the controls, xylanase treatments affected(P < 0.05) the proportions of 5 bacterial taxa in the ileum(f. Peptostreptococcaceae, order [o.]Streptophyta, f. Clostridiaceae, g. Clostridium and g. Streptococcus) and 8 in the cecum(g. Lactobacillus,g. Streptococcus, class [c.] Clostridia, f. Clostridiaceae, g. Megasphaera, g. Prevotella, g. Roseburia and f.Ruminococcaceae). Network analysis showed that across diets under control treatments, Bacteroidetes was the most influential phylum promoting cooperative relationships among members of the ileum and cecum microbiota. Xylanase treatment, however, reduced the influence of Bacteroidetes and promoted a large number of hub taxa majority of which belonged to the Firmicutes phylum. To maximize the efficiency of xylanase supplementation, our data suggest that xylanase C originated from Bacillus subtilis was more effective when applied to wheat-based diets, while xylanase A originated from Fusarium verticillioides was more beneficial when applied to corn-based diets.

The biosynthesis and wall-binding of hemicelluloses in cellulose-deficient maize cells:An example of metabolic plasticity

Cell-suspension cultures（Zea mays L.,Black Mexican sweet corn） habituated to 2,6-dichlorobenzonitrile（DCB） survive with reduced cellulose owing to hemicellulose network modification. We aimed to de fine the hemicellulose metabolism modifications in DCB-habituated maize cells showing a mild reduction in cellulose at different stages in the culture cycle. Using pulse-chase radiolabeling, we fed habituated and non-habituated cultures with [3H]arabinose,and traced the distribution of 3H-pentose residues between xylans, xyloglucans and other polymers in several cellular compartments for 5 h. Habituated cells were slower taking up exogenous [3H]arabinose. Tritium was incorporated into polysaccharide-bound arabinose and xylose residues, but habituated cells diverted a higher proportion of their new [3H]xylose residues into（hetero） xylans at the expense of xyloglucan synthesis. During logarithmic growth, habituated cells showed slower vesicular traf ficking of polymers,especially xylans. Moreover, habituated cells showed a decrease in the strong wall-binding of all pentose-containing polysaccharides studied; correspondingly, especially in log phase cultures, habituation increased the proportion of 3H-hemicelluloses（[3H]xylans and [3H]xyloglucan） sloughed into the medium. These findings could be related to the cel walls’ cellulose-deficiency, and consequent reduction in binding sites for hemicelluloses; the data could also re fl ect the habituated cells’ reduced capacity to integrate arabinox ylans by extra-protoplasmic phenolic cross-linking, as well as xyloglucans, during wall assembly.

Feed endoxylanase type and dose affect arabinoxylan hydrolysis and fermentation in ageing broilers☆

Despite the general use of endoxylanases in poultry feed to improve broiler performance,the abundance of different endoxylanase products and the variable response to their application in the field prevent a clear understanding of endoxylanase functionality in vivo.To gain insight into this functionality,we investigated the impact of endoxylanase type(Belfeed from Bacillus subtilis versus Econase XT from Nonomuraea flexuosa)and dose(10,100,1,000 mg/kg)in combination with broiler age on arabinoxylan(AX)hydrolysis and fermentation in broilers(Ross 308)fed a wheat-soy based diet.In a digestibility trial and a performance trial,a total of 1,057 one-day-old chicks received the control diet or 1 of the 6 endoxylanase supplemented wheat-soy based diets with,respectively,5 replicate cages and 8 replicate pens per dietary treatment per trial.The AX content and structure,the AX digestibility values and the short-chain fatty acids produced were analysed at the level of the ileum,caeca and excreta at d 11 and 36.Endoxylanase supplementation resulted in a more extensive solubilisation of wheat AX and a reduction in the intestinal viscosity compared to the control(P<0.05).A high endoxylanase dose was,however,required to obtain increased hydrolysis of the dietary AX along the gastrointestinal tract against the control(P<0.001).Depending on the type of endoxylanase,a pool of AX with distinct physicochemical properties was created.The B.subtilis endoxylanase created a large pool of soluble AX in the ileum,thereby increasing ileal viscosity compared to broilers fed an endoxylanase from N.flexuosa(P<0.001).The N.flexuosa endoxylanase mainly triggered caecal AX fermentation in young broilers,by delivering easily fermentable AX substrates with a low degree of polymerisation(P=0.03).The effects were particularly present in young broilers(d 11).From this study,it is clear that the type and dose of endoxylanase added to wheat-soy based diets determine the nature of AX substrates formed.These,in turn,affect the intestinal viscosity and the interplay between the dietary AX compounds and microbiota,hence dictating AX digestion at young broiler ages and performance outcomes towards slaughter age.

Interaction between xylanase and a proton pump inhibitor on broiler chicken performance and gut function

Three hundred thirty-six Ross 308 male broiler chicks were used in a 21-d study to explore performance and gut function when treated with a proton pump inhibitor(PPI;0 or 89 mg/kg)in a 2×2 factorial arrangement with a xylanase(Xyl;0 or 0.1 g/kg)to determine if the beneficial activity of arabinoxylan(AX)depolymerisation,through arabinoxylo-oligosaccharides(AXOS)production,starts in the upper gastrointestinal tract.Treatment with the PPI started from d 14,and by d 21 animal performance had deteriorated(P<0.001).An interaction was observed between PPI and Xyl for feed conversion ratio(FCR)(P<0.05),whereby the combination reduced the negative effect of PPI on FCR.Application of PPI raised digesta pH in the gizzard and caecum(P<0.05),increased protein concentrations in the lower gut(P<0.05)and reduced intake of digestible nutrients(P<0.05).Caecal concentrations of indole,p-cresol,ammonia and the ratio of total volatile fatty acid(VFA)to butyric acid were increased with PPI(P<0.05),indicating enhanced protein fermentation.Xylanase activity in the digesta were greatest in the caeca,especially when Xyl was supplemented(P<0.001).The concentration of total soluble AX was greater in the gizzard and ileal digesta with Xyl supplementation(P<0.05),supporting the depolymerisation action of xylanase even under acidic conditions.These data suggest xylanase may function in the gizzard even though pH is not optimal for activity and emphasises the importance of chlorohydric acid secretions in ensuring overall optimum gut function.AX depolymerisation benefits animal performance although it is still unknown how the AXOS produced with xylanase supplementation in the upper gastrointestinal tract influence the microbial populations and overall gut functionality.