Short-term effect of supplemental yeast extract without or with feed enzymes on growth performance, immune status and gut structure of weaned pigs challenged with Escherichia coli lipopolysaccharide

Background： This study investigated the response of piglets receiving a yeast extract without or with a multi-enzyme mixture compared with an antimicrobial growth promoter（AGP） on performance, immune status and gut structure after an E. coli lipopolysaccharide（LPS） challenge. Thirty-six pigs were allotted to six treatments including： a non-challenged control（NCC）; LPS-challenged control（CC）; CC ＋ AGP; CC ＋ yeast extract; CC ＋ enzymes; and CC ＋ enzymes ＋ yeast extract. On d 7, pigs were bled and thereafter injected with LPS or sterile saline. Blood samples were collected at 6, 48, and 96 h post-challenge. After 96 h post-challenge, pigs were euthanized to obtain duodenal, jejunal and ileal samples.Results： Overall（d 1 to 11）, compared with CC pigs, AGP attenuated the LPS-induced reduction in ADG（P = 0.004）,ADFI（P = 0.03） and gain/feed ratio（P = 0.01）. At 6 h post-challenge, AGP pigs had lower plasma urea N（PUN; P = 0.02）and serum TNF-α concentration（P = 0.07）, and higher platelet count（P = 0.04） and serum IL-10 concentration（P = 0.02） than CC pigs. At 48 h post-challenge, AGP pigs had lower PUN（P = 0.02） than CC pigs, whereas enzymes ＋ yeast extract interacted non-additively（P = 0.001） to reduce PUN. At 96 h post-challenge, AGP pigs had lower PUN（P = 0.02）and higher duodenal（P = 0.03）, jejunal（P = 0.01） and ileal（P = 0.07） villus height than CC pigs. In addition, enzymes ＋yeast extract interacted additively and non-additively to reduce ileal IFN-γ（P 0.10） were observed between AGP and enzymes ＋ yeast extract pigs on other measured parameters except for the downregulation of ileal IFN-γ（P ＆lt; 0.0001） and TNF-α（P = 0.003） in enzymes ＋ yeast extract pigs at 96 h post-challenge.Conclusions： The LPS challenged piglets receiving enzymes ＋ yeast extract showed beneficial responses in gut structure and immunity commensurate with those receiving antibiotics, though the latter had better overall growth performance.

Cereal type and combined xylanase/glucanase supplementation influence the cecal microbiota composition in broilers

Dietary fiber-degrading enzyme supplementation in broilers aims at off-setting the anti-nutritive effect of non-starch polysaccharides and at promoting broiler health.Recently,we demonstrated that xylanase/glucanase addition in wheat-based diet improved nutrient digestibility,arabinoxylan fermentability and broiler growth.Conversely,maize arabinoxylan was found to be recalcitrant to xylanase action.These findings suggested that enzyme-mediated improvement of nutrient digestion and carbohydrate fermentation depended on the cereal type present in the diet,and may have contributed to broiler growth.Hence,we aimed at further investigating the link between dietary enzymes and carbohydrate fermentation in broilers,by studying the impact of enzyme supplementation in cereal-based diets,to the microbial communities in the ileum and ceca of broilers.For that purpose,96 one-day-old male broilers were randomly reared in two pens and received either wheat-based or maize-based starter and grower diets.At d 20,the broilers were randomly assigned to one out of four dietary treatments.The broilers received for 8 d the wheat-based or maize-based finisher diet as such(Control treatments;WC,MC)or supplemented with a xylanase/glucanase combination(Enzyme treatments;WE,ME).At d 28,samples from the digestive tract were collected,and the ileal and cecal microbiota composition was determined by 16S ribosomal RNA gene amplicon sequencing.A similar phylogenetic(alpha)diversity was observed among the four treatments,both in the ileal and the cecal samples.Furthermore,a similar microbial composition in the ileum(beta diversity)was observed,with lactobacilli being the predominant community for all treatments.In contrast,both cereal type and enzyme supplementation were found to influence cecal communities.The type of cereal(i.e.,wheat or maize)explained 47% of the total variation in microbial composition in the ceca.Further stratifying the analysis per cereal type revealed differences in microbiota composition between WC and WE,but not between MC and ME.Furthermore,the prevalence of beneficial genera,such as Faecalibacterium and Blautia,in the ceca of broilers fed wheat-based diets coincided with arabinoxylan accumulation.These findings indicated that fermentable arabinoxylan and arabinoxylo-oligosaccharides released by dietary xylanase may play an important role in bacterial metabolism.

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.

Hulless barley and β-glucanase affect ileal digesta soluble β-glucan molecular weight and digestive tract characteristics of coccidiosis-vaccinated broilers

Exogenousβ-glucanase(BGase)in barley-based feed has been shown to reduce digesta viscosity in chickens,and thereby improve performance.Less well studied is the potential for BGase to convert barleyβ-glucan into low molecular weight carbohydrates,which might influence digestive tract function and enteric disease.Coccidiosis-vaccinated broiler chickens were fed graded levels of hulless barley(HB)and BGase to determine their effects onβ-glucan depolymerization and digestive tract characteristics.Broilers were fed highβ-glucan HB(0%,30%and 60%replacing wheat)and BGase(0%,0.01%and 0.1%)in a 3×3 factorial arrangement.A total of 5,346 broilers were raised in litter floor pens and vaccinated for coccidiosis on d 5.Each treatment was assigned to 1 pen in each of 9 rooms.The significance level was set at P≤0.05.At both 11 and 33 d of broiler ages,peak molecular weight ofβ-glucan in ileal digesta decreased with increasing BGase for 30%and 60%HB.The maximum molecular weight for the smallest 10%β-glucan molecules(MW-10%)decreased with BGase at both ages for 30%and 60%HB;for birds fed 0%HB,only 0.1%BGase decreased MW-10%.The 0.1%BGase increased caecal short chain fatty acids(SCFA)compared to the 0.01%BGase at d 11 only for the 60%HB.Ileal pH increased with increasing HB and BGase at d 11 and 33.Caecal pH was lower for 0.1%BGase than 0%BGase for 60%HB at d 11.Relative mRNA expression of interleukin 6(IL-6)and IL-8 in the ileum increased with 0.1%BGase at d 11 and 33,respectively,whereas expression of ileal mucin 2(MUC2)decreased with 0.1%BGase at d 33.In the caeca,interactions between HB and BGase were significant for monocarboxylate transporter 1(MCT1)and mucin 5AC(MUC5AC)on d 11,but no treatment effects were found at d 33.In conclusion,BGase depolymerized high molecular weightβ-glucan in HB in a dose-dependent manner.Hulless barley and BGase did not increase SCFA concentrations(except for 60%HB with 0.1%BGase at d 11)and caused minor effects on digestive tract histomorphological measurements and relative mRNA gene expression.