Dietary supplementation with xylooligosaccharides and exogenous enzyme improves milk production,energy utilization efficiency and reduces enteric methane emissions of Jersey cows

Background Sustainable strategies for enteric methane(CH_(4))mitigation of dairy cows have been extensively explored to improve production performance and alleviate environmental pressure.The present study aimed to investigate the effects of dietary xylooligosaccharides(XOS)and exogenous enzyme(EXE)supplementation on milk production,nutrient digestibility,enteric CH_(4) emissions,energy utilization efficiency of lactating Jersey dairy cows.Forty-eight lactating cows were randomly assigned to one of 4 treatments:(1)control diet(CON),(2)CON with 25 g/d XOS(XOS),(3)CON with 15 g/d EXE(EXE),and(4)CON with 25 g/d XOS and 15 g/d EXE(XOS+EXE).The 60-d experimental period consisted of a 14-d adaptation period and a 46-d sampling period.The enteric CO_(2)and CH_(4) emissions and O2 consumption were measured using two GreenFeed units,which were further used to determine the energy utilization efficiency of cows.Results Compared with CON,cows fed XOS,EXE or XOS+EXE significantly(P<0.05)increased milk yield,true protein and fat concentration,and energy-corrected milk yield(ECM)/DM intake,which could be reflected by the significant improvement(P<0.05)of dietary NDF and ADF digestibility.The results showed that dietary supplementation of XOS,EXE or XOS+EXE significantly(P<0.05)reduced CH_(4) emission,CH_(4)/milk yield,and CH_(4)/ECM.Furthermore,cows fed XOS demonstrated highest(P<0.05)metabolizable energy intake,milk energy output but lowest(P<0.05)of CH_(4) energy output and CH_(4) energy output as a proportion of gross energy intake compared with the remaining treatments.Conclusions Dietary supplementary of XOS,EXE or combination of XOS and EXE contributed to the improvement of lactation performance,nutrient digestibility,and energy utilization efficiency,as well as reduction of enteric CH_(4) emissions of lactating Jersey cows.This promising mitigation method may need further research to validate its long-term effect and mode of action for dairy cows.

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.

Fast saccharide mapping method for quality consistency evaluation of commercial xylooligosaccharides collected in China

Due to the extensive use of xylooligosaccharides(XOS)as functional food ingredients,many inferior goods and even adulterants are generally found in the market,which may pose a health hazard to certain populations.Chromatography method such as high-performance liquid chromatography(HPLC)and high-performance thin-layer chromatography(HPTLC)is traditionally applied for the quality analysis of XOS.However,it is time consuming due to the prolonged separation and pre-or post-derivatization procedure.In this study,a fast saccharide mapping method based on matrix-assisted laser desorption/time-of-flight mass spectrometry(MALDI-TOF-MS)was developed for the quality consistency analysis of 22 batches of XOS collected from different manufacturers in China.The time needed for saccharides analysis using MALDI-MS was less than 30 min for one plate,at least 6 times faster than that by the traditional HPTLC chromatography method.In addition,MALDI-MS possessed higher resolution for XOS with DP4-DP7 based on the difference of m/z,which is hardly separated using HPTLC.The results showed that XOS were present only in samples XY01-XY11,samples XY12-XY14 only consisted of hex oligosaccharides,and samples XY15-XY22 were free of oligosaccharides.These indicate that the quality consistency of XOS products in the China market was poor,which should be carefully investigated.

Xylooligosaccharides (XOS) as Emerging Prebiotics: Its Production from Lignocellulosic Material

Prebiotics are non-digestible food supplements (oligosaccharides) which play an important role in stimulating the growth of beneficial bacteria especially Lactobacilli and Bifidobacteria in the colon of the host. Xylooligosaccharides (XOS) are more effective than other oligosaccharides such as fructo-oligosaccharides as dietary supplements. Chemical methods are preferred to produce XOS mixtures with a wide DP range, while enzymatic methods are preferred in the food or pharmaceutical industries to reduce formation of degradation products. With the growing importance of making fuels fromlignocellulosic biomass (LCM) and the increasing demand for XOS, more opportunities are emerging to utilize xylan-rich component generated in biorefinery into high-value products such as XOS that could further lower the cost of LCM derived biofuels.

Effects of Adding Different Levels of Xylooligosaccharides (XOS) in Diet on Reproduction Performance of Lactating Sows

[Objective] The paper was to investigate effects of adding xylooligosaccharides( XOS) in diet on reproduction performance of lactating sows.[Method]Fifty healthy multiparous sows( Landrace × Yorkshire,3-4 fetuses) with similar parity,body condition and expected date of childbirth were randomly divided into five treatments,10 repeats each treatment,and each treatment contained an individual sow. Treatment 1 was control group( basal diet); treatment 2,treatment 3,treatment 4 and treatment 5 were adding 0. 025%,0. 050%,0. 075% and 0. 100% XOS in the basal diet,respectively. The trial lasted 35 d from 90 d of gestation until weaning. [Result]Compared to control group( treatment 1),there was no significant difference in reproduction performance of sows among four experimental groups( P > 0. 05). With the increasing addition amount of XOS,the production process of sows was shortened; the weaning back fat thickness in treatment 2,treatment 3 and treatment 4 slightly increased,while the estrus intervals in treatment 2,treatment 3,treatment 4 and treatment 5 were shortened.[Conclusion]It was the most economic and effective by adding 0. 050% XOS in the sows diet.

Regulatory Effects of Xylooligosaccharides on Intestinal Microbial Flora Proliferation and Defecation of BALB/c Mice

[ Objective] This study aimed to investigate the regulatory effects of xylooligesaccharides on intestinal microbial flora proliferation and defecation of BALB/c mice. [Method] In the intestinal microbial flora proliferation regulation experiment, microflom quantities of Bifidobacterium, Lactobacillus, Enterobacter and Enterococci in excrements of BALB/c mice were determined after continuous administration of high-dose[ 1.0 g/（ kg ~ bw ） ] and low-dose[ 0.5 g/（ kg ~ bw ） ] xylooligosaccharides for 14 d. In the defecation regulation experiment, constipation model of BALB/c mice was established with compound diphenexylate after con- tinuous administration of high-dose and low-dose xylooligosaccharides for 21 d, to determine the first defecation time of black excrement, weight of black excrements within 6 h and rate of intestinal propulsion of constipation mice. [ Result] Compared with the control group, after continuous administration of xyloolignsaccharides for 14 d, microflora quantifies of Lactobac//lus and B/fidobacter/um in excrements of BALB/c mice in low-dose and high-dose groups both increased significantly （ P 〈 0.05 ）. After continuous administration of xylooligosaccharidos, microflora quantities of Enterococci and Lactobacillus in control group were significantly raised （P 〈 O. 05 and P 〈 0.01, respectively） compared with those before administration; mieroflora quantities of Enterococci in high-dose and low-dose groups were signif- icantly reduced （P 〈0.05）, while microflora quantities of/zwtobac//lus and B/fidobacter/um and the B/E value increased significantly （P 〈0. 05, P 〈0.01 and P 〈 0.01, respectively）. After continuous administration of xylooligosaccharides for 21 d, compared with the model group, the first defecation time of black excre- ment in high-dose and low-dose groups was significantly shortened （ P 〈 O. 05 ）, the total weight of black.excrements within 6 h increased significantly （ P 〈 0.05 ） and the rate of intestinal propulsion was significantly enhanced （ P 〈0.01 ）. [ Conclusion ] Low-dose （0.5 g/Kg. bw） and high-dose （ 1 g/Kg. bw） xylooligosac- charides can improve the proliferation of intestinal microbial flora and prevent mice from constipation.

Effects of supplemental xylanase and xylooligosaccharides on production performance and gut health variables of broiler chickens

Background:This study evaluated the effects of supplemental xylanase and xylooligosaccharides(XOS)in a cornsoybean meal(SBM)-based diet on growth performance and intestinal health of broilers.A total of 288 day-old chicks(Cobb 500)were allocated to 36 floor pens(8 birds/pen)equally in 9 dietary treatments in a 3×3 factorial arrangement.The treatments were combinations of 3 levels of xylanase(0,0.005% and 0.01% Econase XT)and 3 levels of prebiotics(0,0.005% and 0.01% XOS)added to basal mash diets formulated in three phases(starter,d 0-14;grower,d 15-28;finisher,d 29-42).The feed intake and body weights were recorded weekly.On d 42,ileal sections were collected for histomorphometric and gene expression analysis,and cecal content was collected for determining short-chain fatty acids(SCFA)and microbiota.Results:Xylanase linearly(P<0.01)increased the average daily gain(ADG)in both the finisher and total period and the final body weight gain(FBWG,2940&2932 vs.2760 g)of broilers.XOS did not significantly increase either ADG or FBWG(P>0.05).Supplemental xylanase and XOS did not affect average daily feed intake and feed conversion ratio(P>0.05).Xylanase and XOS did not change villus height(VH)or crypt depth(CD)ratio(P>0.05).However,xylanase exhibited a trend(P=0.097)on VH:CD ratio.The inclusion of 0.01%XOS without xylanase increased the level of IL-10(a marker of anti-inflammatory cytokine)and IL-4(a T-cell differentiation cytokine)genes compared with control(P<0.05).The acetate production was increased by xylanase(P<0.01)and XOS(P<0.05)without an additive effect.Xylanase increased total SCFA(P<0.01)while XOS had a tendency to increase(P=0.052).Alpha and beta diversity of microbiota among treatments were not different(P>0.05).However,the mean proportion of family Ruminococcaceae was increased by the supplemental 0.01% xylanase(P<0.01).Conclusion:It can be concluded that XOS can enhance cecal fermentation,while xylanase can increase the body weight gain along with the fermentation metabolites in the ceca of broilers fed the corn-SBM-based diet but the effects may not always translate into an improved mucosal absorptive capacity and a better feed efficiency.

Efficacy of Xylooligosaccharides and Probiotics Additive to the Diets of Sows and/or Piglets on Performance,Milk Composition and Appearance of Diarrhea in Sows and Their Offspring

The present study investigated the effects of dietary supplementation of xylooligosaecharides （XOS） and probiotics （PR） on performance, milk compo- sition and diarrhea incidence of sows or their offspring. From day 90 of gestation until weaning, a total of 60 muhiparous sows were randomly assigned to three groups and given three different diets that included either the control diet （ sCON, n = 20 ）, the control diet containing 175 mg/kg XOS （ sXOS, n = 20 ） or 175 mg/kg XOS and 300 mg/kg probiotics （sXOS ＋ PR, n =20）. On day 21 of age, offspring were assigned within sow treatments to the piglet basal diet （pCON） or the piglet basal, diet supplemented with 175 mg/kg XOS （pXOS） for 28 d. Sow feed intake was recorded daily. Body weight and feed consumption of the pigs in each replicate were determined biweekly （on day 0, 14 and 28） to calculate the average daily gain （ADG） of body weight, average daily feed intake （ADFI） and the gain-to-feed ratio （ G： F）. The colostrum and milk samples were obtained on day 0 and 14 of lactation, respectively. Sow XOS or XOS ＋ PR dietary had no effect on the number of total piglets born and born alive and the piglet weight at birth. Milk composition in sow colostrum and milk were not affected by sow diet XOS or （ XOS ＋ PR） supplementation （ P 〉 0.05 ）. No maternal dietary effect was observed on the weaning weight and pre-weaning weight gains of piglets. However, there were interaction effects between sow and piglet dietary treatments on diarrhea rate and diarrhea index during day 35 -49 （P = 0.03 ） and day 21 -49 （P =0.02）. Although sow diet XOS and （XOS ＋ PR ） supplementation did not influence growth performance of weanling piglets, such as ADG and ADFI （ P 〉0.05 ）, piglets XOS supplementation significantly decreased ADFI during the whole experiment period and increased G： F during day 35 -49 and day 21 -49 （ P 〈0.05 ）. These results might suggest that combination of XOS and PR in sow diets had negative impact on the diarrhea incidence of offspring. XOS supplementation in weaned piglet diets decreased ADFI and feed conversion efficiency of weaning piglets.

Effect of in ovo feeding of xylobiose and xylotriose on plasma immunoglobulin, cecal metabolites production, microbial ecology, and metabolic pathways in broiler chickens

Background Dietary supplementation of xylooligosac charides(XOS) has been found to influence gut health by manipulating cecal microbiota and producing microbe-origin metabolites.But no study investigated and compared the effect of in ovo feeding of xylobiose(XOS2) and xy lotriose(XOS3) in chickens.This study investigated the effect of in ovo feeding of these XOS compounds on post-hatch gut health parameters in chickens.A total of 144 fertilized chicken eggs were divided into three groups:a) non-injected control(CON),b) XOS2,and c) XOS3.On the 17^(th) embryonic day,the eggs of the XOS2 and XOS3 groups were injected with 3 mg of XOS2 and XOS3 diluted in 0.5 mL of 0.85% normal saline through the amniotic sac.After hatching,the chicks were raised for 21 d.Blood was collected on d 14 to measure plasma immunoglobulin.Cecal digests were collected for measuring short-chain fatty acids(SCFA) on d 14 and 21,and for microbial ecology and microbial metabolic pathway analyses on d 7 and 21.Results The results were considered significantly different at P<0.05.ELISA quantified plasma IgA and IgG on d 14chickens,revealing no differences among the treatments.Gas chromatography results showed no significant differences in the concentrations of cecal SCFAs on d 14 but significant differences on d 21.However;the SCFA concentrations were lower in the XOS3 than in the CON group on d 21.The cecal metagenomics data showed that the abundance of the family Clostridiaceae significantly decreased on d 7,and the abundance of the family Oscillospiraceae increased on d 21 in the XOS2 compared to the CON.There was a reduction in the relative abundance of genus Clostridium sense stricto 1 in the XOS2 compared to the CON on d 7 and the genus Ruminococcus,torques in both XOS2 and XOS3 groups compared to the CON on d 21.The XOS2 and XOS3 groups reduced the genes for chondroitin sulfate degradation Ⅰ and L-histidine degradation Ⅰpathways,which contribute to improved gut health,respectivelyc in the microbiome on d 7.In contrast,on d 21,the XOS2 and XOS3 groups enriched the thiamin salvage Ⅱ,L-isoleucine biosynthesis Ⅳ,and O-antigen building blocks biosynthesis(E. coli) pathways,which are indicative of improved gut health.Unlike the XOS3 and CON,the microbiome enriched the pathways associated with energy enhancement,including flavin biosynthesis Ⅰ,sucrose degradation Ⅲ,and Calvin-Benson-Bassham cycle pathways,in the XOS2 group on d 21.Conclusion In ovo XOS2 and XOS3 feeding promoted beneficial bacterial growth and reduced harmful bacteria at the family and genus levels.The metagenomic-based microbial metabolic pathway profiling predicted a favorable change in the availability of cecal metabolites in the XOS2 and XOS3 groups.The modulation of microbiota and metabolic pathways suggests that in ovo XOS2 and XOS3 feeding improved gut health during the post-hatch period of broilers.

Stimbiotic supplementation modulated intestinal inflammatory response and improved broilers performance in an experimentally-induced necrotic enteritis infection model

Background:Two experiments were conducted to establish an optimal NE challenge model and evaluate the efficacy of stimbiotic(STB)supplementation in necrotic enteritis(NE)challenged broilers.In Exp.1,a total of 120 Arbor Acres(AA)broilers(45.0±0.21 g)were randomly assigned to 6 treatments in a 3×2 factorial arrangement.Vaccine treatments included non-challenge(0),×10 the recommended dose(×10)or×20 the recommended dose(×20)by the manufacturer.Clostridium perfringens(CP)treatments were non-challenge(No)or 3 mL of 2.2×10^(7)CFU CP challenge(Yes).In Exp.2,a total of 72 AA broilers(40.17±0.27 g)were randomly assigned to 6 treatments in a 3×2 factorial arrangement.Dietary treatments included non-additive(CON),100 mg/kg STB(STB)and 100 mg/kg STB on top of a typical commercial blend including an essential oil,probiotics,and enzyme(CB).Challenge treatments included non-NE challenge(No)and NE challenge(Yes)as established in Exp.1.Results:In Exp.1,CP and vaccine challenge decreased(P<0.05)body weight(BW),body weight gain(BWG)and feed intake(FI),and increased(P<0.05)the number of broilers with diarrhea and intestinal lesions.The oral administration of×20 recommended dose of vaccines coupled with 3 mL of 2.2×10^(7)CFU CP resulted in(P<0.01)a significantly increased incidence of wet litter and intestinal lesions.Thus,this treatment was chosen as the challenge model for the successful inducement of NE in Exp.2.In Exp.2,the NE challenge negatively affected(P<0.01)growth performance,ileal morphology,immunoglobulin contents in blood,caecal microbiota in the caecum,footpad dermatitis,intestinal lesion scores,tumour necrosis factor(TNF-α)and endotoxin in the serum compared with the non-NE challenged birds.The supplementation of STB and CB in diets enhanced(P<0.05)growth performance,intestinal microbiota,and blood profiles by stimulating ileal morphology(VH and VH:CD)and propionate production in the cecum,and there were no differences in measured variables between STB and CB supplemented birds.Conclusion:Overall,these results indicate that STB supplementation was able to reduce the inflammatory response and improve the performance of NE challenged birds,and the supplementation of STB alone was as effective as a typical commercial blend containing a number of other additives.

Effects of in ovo delivered xylo-and mannan-oligosaccharides on growth performance,intestinal immunity,cecal short-chain fatty acids,and cecal microbiota of broilers

Background:This study investigated a novel in ovo feeding strategy to determine the prebiotic effects of xylo-and mannan-oligosaccharides(XOS and MOS)differing in the degree of polymerization.A total of 192 fertilized eggs were divided into 6 treatment groups:i)normal saline control(NSC),ii)xylotriose(XOS3),iii)xylotetraose(XOS4),iv)mannotriose(MOS3),v)mannotetraose(MOS4),and vi)no injection control(NIC),each containing 4 replicate trays with 8 eggs per replicate.On d 17 of incubation,3 mg of oligosaccharides(except for controls)dissolved in 0.5 mL of 0.85%normal saline were injected into the amnion of Cobb 500 broilers eggs.After hatch,the chicks were raised for 28 d under standard husbandry practices and were fed a commercial broilers diet ad libitum,and samples were collected periodically.Results:The hatchability,growth performance,and relative weights of breast,drumstick,liver,and proventriculus were not different among the treatments(P>0.05).The XOS3 injection increased the total short-chain fatty acid production at d 28 compared with both control groups(P<0.05).The villus height to crypt depth ratio was significantly higher in the XOS4 group than both controls on the hatch day(P<0.01)but were not different among any treatments on d 7 and 28(P>0.05).On the hatch day,the expression level of the CD3 gene(a T cell marker)was increased by XOS3,while the IL-10 gene(a marker of anti-inflammatory cytokine)was reduced by MOS4(P<0.05)compared with both controls.Compared with both controls,XOS3 exhibited a trend of reduction for IL-10(P=0.074).No cytokines or lymphocyte markers were affected by the treatments on d 7(P>0.05),except XOS4 increased IL-4 compared with NSC(P<0.05).The broilers in the MOS4 group had higher operational taxonomic units(OTUs)and had more differentially abundant taxa,including order Lactobacillales and family Leuconostocaceae(P<0.05)than both controls on d 28.The predictive functional profiling indicated that the linoleic acid metabolism pathway was enriched in the cecal microbiota of the XOS3 group compared with both controls(P<0.05).Conclusion:The effects of these XOS and MOS on ileal mucosa and immunity are transient,but the effects on fermentation and cecal microbiota are prolonged,and further research is warranted to determine their use as a gut health promoter in poultry.

Cloning of an α-L-Arabinofuranosidase and Characterization of Its Action on Mono- and Di-Substituted Xylopyranosyl Units

An α-L-arabinofuranosidase (ARF) gene of 1503 bp was synthesized, subcloned into pET26b vector, and expressed in Escherichia coli. The enzyme was purified in active form, and consisted of 500 amino acid residues, corresponding to 55 kD based on SDS-PAGE. The affinity-purified protein was characterized using arabinofuranosyl xylooligosaccharides (AXOS) as substrates. The pH effect was investigated showing an optimum at pH 5.5. XaARF catalyzed the cleavage of arabinose at C3 of the xylopyranosyl unit efficiently if the arabinofuranosyl substitution was at the terminal compared to internal xylose units. The enzyme was able to act on di-substituted xylopyranosyl units with the first cleavage at C3 followed by C2 linkages.

Effects of Xylooligosaccharide(XOS)and Probiotics(PRO)on Production Performance,Egg Quality and Intestinal Short-chain Fatty Acids of Laying Hens in Late Laying Period

[Objective]The paper was to study the effects of xylooligosaccharide(XOS)and probiotics(PRO)and their interaction on the production performance,egg quality and intestinal short-chain fatty acids of laying hens in late laying period.[Method]A total of 36074-week-old Romain brown laying hens were randomly divided into four groups,six replicates each group and 15 chickens each replicate.The trial lasted 63 d.The laying hens in control group(CON)were fed with basal diet,and those in experimental groups were fed with the basal diets adding with 150 mg/kg XOS(XOS group),100 mg/kg probiotics(PRO group),150 mg/kg XOS+100 mg/kg probiotics(XOS-PRO group).[Result]Compared with the control group,the laying rate,daily egg production,yolk ratio,colonic acetic acid and caecal propionic acid in XOS group increased significantly(P<0.05),and the feed gain ratio decreased remarkably(P<0.05).PRO had no significant effect on the production performance and egg quality of laying hens in late laying period(P>0.05),but significantly increased colonic acetic acid(P<0.05).XOS and PRO had no interaction effect on the production performance,egg quality and intestinal short-chain fatty acids of laying hens in late laying period(P<0.05).[Conclusion]Adding XOS to the diet of laying hens in late laying period could increase the content of short-chain fatty acids in the hindgut of laying hens,and effectively improve the production performance and egg quality of laying hens in late laying period.Adding PRO to the diet did not significantly improve the production performance and egg quality of laying hens,and there was no interaction effect between XOS and PRO.

Dietary supplemental xylooligosaccharide modulates nutrient digestibility,intestinal morphology,and gut microbiota in laying hens

This study was conducted to evaluate the prebiotic effects of dietary xylooligosaccharide(XOS)sup-plementation on performance,nutrient digestibility,intestinal morphology,and gut microbiota in laying hens.In a 12-wk experiment,a total of 288 Hy-Line Brown layers at 50 wk of age were randomly assigned into 3 dietary treatments supplemented with XOS at 0,200 or 400 mg/kg.Each treatment had 8 replicates with 12 birds each.Hens fed XOS diets showed a lower feed-to-egg ratio during wk 7 to 12 and a higher egg yolk color value in wk 12 compared with those fed the control diet(P<0.05).Dietary XOS supplementation improved the apparent total tract digestibility of gross energy and nitrogen at the end of the 12th wk(P<0.05).In addition,a higher villus height-to-crypt depth ratio of the ileum was observed in XOS-added groups(P<0.05).The high throughput sequencing analysis of bacterial 16S rRNA revealed that dietary XOS supplementation at 200 mg/kg altered cecal microbiota.Alpha diversity analysis illustrated a higher cecal bacterial richness in birds fed with XOS at 200 mg/kg.The composition of cecal microbiota modulated by the XOS addition was characterized by an increased abundance of Firmicutes along with a reduced abundance of Bacteroidetes.At the genus level,dietary XOS supple-mentation triggered decreases in Bacteroides and Campylobacter concurrent with increases in Lactoba-cillus and several short chain fatty acid producers including Desulfovibrio,Faecalitalea,Faecalicoccus,and 5 genera of family Lachnospiraceae.Collectively,dietary XOS addition improved the feed conversion ratio by modulating nutrient digestibility and ileal morphology in laying hens,which could be attributed to the enhancement of bacterial diversity and alteration of microbial composition.

Xylooligosaccharide attenuates lipopolysaccharide-induced intestinal injury in piglets via suppressing inflammation and modulating cecal microbial communities

Xylooligosaccharide(XOS)has been considered to be an effective prebiotic,but its exact mechanisms remain unknown.This research was conducted to evaluate the effects of XOS on pig intestinal bacterial community and mucosal barrier using a lipopolysaccharide(LPS)-caused gut damage model.Twenty-four weaned pigs were assigned to 4 treatments in a 2×2 factorial design involving diet(with or without XOS)and immunological challenge(saline or LPS).After 21 d of feeding 0%or 0.02%commercial XOS product,piglets were treated with saline or LPS.After that,blood,small intestinal mucosa and cecal digesta were obtained.Dietary XOS enhanced intestinal mucosal integrity demonstrated by higher villus height,villus height-to-crypt depth ratio,disaccharidase activities and claudin-1 protein expression and lower crypt depth.XOS also caused down-regulation of the gene expression of toll-like receptor 4 and nucleotide-binding oligomerization domain protein signaling,accompanied with decreased pro-inflammatory cytokines and cyclooxygenase 2 contents or mRNA expression and increased heat shock protein 70 mRNA and protein expression.Additionally,increased Bacteroidetes and decreased Firmicutes relative abundance were observed in the piglets fed with XOS.At the genus level,XOS enriched the relative abundance of beneficial bacteria,e.g.,Faecalibacterium,Lactobacillus,and Prevotella.Moreover,XOS enhanced short chain fatty acids contents and inhibited histone deacetylases.The correlation analysis of the combined datasets implied some potential connections between the intestinal microbiota and pro-inflammatory cytokines or cecal metabolites.These results suggest that XOS inhibits inflam-matory response and beneficially modifies microbes and metabolites of the hindgut to protect the in-testine from inflammation-related injury.