Dietary fibers with low hydration properties exacerbate diarrhea and impair intestinal health and nutrient digestibility in weaned piglets

Background:This study aimed to investigate the hydration properties of different-source fibrous materials by com-paring their water-binding capacity(WBC),water swelling capacity(WSC),viscosity,and in vivo effects of selected samples on growth performance,nutrient digestibility,diarrhea,and intestinal health in weaned piglets.Methods:A total of 13 commercially available fibrous materials were first compared in chemical composition and in vitro hydration property.Subsequently,40 weaned piglets were randomized to five experimental dietary groups(8 piglets per group):control diet(a basal diet without dietary fiber,CON),basal diet supplemented with 5%microcrys-talline cellulose(MCC),5%wheat bran(WB),5%Moringa oleifera leaf powder(MOLP),or 5%sugar beet pulp(SBP),fol-lowed by analyzing their growth performance and diarrhea rate in a 28-d experiment.After the feeding experiment,anaesthetized piglets were killed,and their intestinal and colon content or plasma samples were analyzed in nutrient digestibility,intestinal morphology,intestinal barrier,short-chain fatty acids(SCFAs),and bacterial population.Results:In vitro studies showed low hydration properties for WB and MCC,while medium hydration properties for MOLP and SBP.In vivo studies indicated that compared with medium hydration property groups,low hydration prop-erty groups showed(1)exacerbated diarrhea,impaired intestinal health,and reduced apparent fecal digestibility of dry matter,gross energy,acid detergent fiber,and neutral detergent fiber;(2)decreased SCFAs concentration and rela-tive levels of Lactobacillus and Bifidobacterium,but increased levels of Escherichia coli and Brachyspira hyodysenteriae in colon contents.Additionally,SBP showed optimal performance in reducing diarrhea and increasing SCFAs produc-tion.Correlation analysis revealed a positive correlation of fiber hydration properties with in vitro SCFAs production,and diarrhea index and nutrient digestibility were negatively and positively correlated with SCFAs levels in the colon contents of weaned piglets,respectively.Conclusions:Different-source dietary fibers varied in their hydration properties and impacts on diarrhea,microbial composition and SCFAs production in weaned piglets.WB and MCC could exacerbate diarrhea and impair nutrient digestibility,probably because their low hydration properties were detrimental to gut microbial homeostasis and fermentation.Our findings provide new ideas for rational use of fiber resources in weaned piglets.

Effects of tannic acid on the immunity and intestinal health of broiler chickens with necrotic enteritis infection

Background In broiler chickens,necrotic enteritis(NE)infection can reduce production performance.Tannic acid has shown great potential as a treatment of NE in broilers.However,the appropriate dosage of tannic acid in NE of broilers and the improvement effect on intestinal health are not very clear.In this study,we aimed to investigate the effects of different doses of tannic acid on the production performance,immunity,and intestinal health of broilers by constructing an NE model with C.perfringens infection and determining the appropriate dosage of tannic acid with regard to NE.Results Challenged birds showed significant reduction in body weight,villus height,and the ratio of villus height to crypt depth(P<0.05)and increase in the feed consumption gain ratio,intestinal lesion score,and crypt depth(P<0.05).The infection significantly reduced the relative Bacteroidota and Ligilactobacillus abundance(P<0.05)and increased the ratio of Firmicutes/Bacteroidota and cecal content of C.perfringens(P<0.05).Challenged birds fed diets supplemented with tannic acid showed significantly increased mRNA expression of nutrient transport carriers and intestinal barrier genes and growth performance and reduced serum zonulin and endotoxin levels(P<0.05).Addi-tion of tannic acid to the diet inhibited the inflammatory response by reducing the number of coccidia oocysts in feces and the content of C.perfringens in the cecum.Specifically,tannic acid reduced the serum levels of C reactive protein,myeloperoxidase,and specific IgY and ileal mucosal secretory immunoglobulin A levels in the ileal mucosa compared with those in the NE-infected birds.NE-infected birds fed diets supplemented with tannic acid also showed significantly increased relative Anaerocolumna,Thermoanaerobacterium,and Thermosinus abundance(P<0.05);their microbial composition and functional predictions were similar to those of the NC group.Conclusions Tannic acid in the diet alleviated NE by enhancing the intestinal barrier and absorption function.The recommended dietary tannic acid additive level is 500–750 mg/kg.Our study findings would be useful in reducing related economic losses in the broiler industry.

Comparative effects of soy protein concentrate,enzyme‑treated soybean meal,and fermented soybean meal replacing animal protein supplements in feeds on growth performance and intestinal health of nursery pigs

Background Soy protein supplements,with high crude protein and less antinutritional factors,are produced from soybean meal by different processes.This study evaluated the comparative effects of various soy protein supplements replacing animal protein supplements in feeds on the intestinal immune status,intestinal oxidative stress,mucosaassociated microbiota,and growth performance of nursery pigs.Methods Sixty nursery pigs(6.6±0.5 kg BW)were allotted to five treatments in a randomized complete block design with initial BW and sex as blocks.Pigs were fed for 39 d in 3 phases(P1,P2,and P3).Treatments were:Control(CON),basal diet with fish meal 4%,2%,and 1%,poultry meal 10%,8%,and 4%,and blood plasma 4%,2%,and 1%for P1,P2,and P3,respectively;basal diet with soy protein concentrate(SPC),enzyme-treated soybean meal(ESB),fermented soybean meal with Lactobacillus(FSBL),and fermented soybean meal with Bacillus(FSBB),replacing 1/3,2/3,and 3/3 of animal protein supplements for P1,P2,and P3,respectively.Data were analyzed using the MIXED procedure in SAS 9.4.Results The SPC did not affect the BW,ADG,and G:F,whereas it tended to reduce(P=0.094)the ADFI and tended to increase(P=0.091)crypt cell proliferation.The ESM did not affect BW,ADG,ADFI,and G:F,whereas tended to decrease(P=0.098)protein carbonyl in jejunal mucosa.The FSBL decreased(P<0.05)BW and ADG,increased(P<0.05)TNF-α,and Klebsiella and tended to increase MDA(P=0.065)and IgG(P=0.089)in jejunal mucosa.The FSBB tended to increase(P=0.073)TNF-α,increased(P<0.05)Clostridium and decreased(P<0.05)Achromobacter and alpha diversity of microbiota in jejunal mucosa.Conclusions Soy protein concentrate,enzyme-treated soybean meal,and fermented soybean meal with Bacillus could reduce the use of animal protein supplements up to 33%until 7 kg body weight,up to 67%from 7 to 11 kg body weight,and entirely from 11 kg body weight without affecting the intestinal health and the growth performance of nursery pigs.Fermented soybean meal with Lactobacillus,however,increased the immune reaction and oxidative stress in the intestine consequently reducing the growth performance.

Dietary oregano aqueous extract improves growth performance and intestinal health of broilers through modulating gut microbial compositions

Background Intestinal health plays a pivotal role in broiler chicken growth.Oregano aqueous extract(OAE)effec-tively exerts anti-inflammatory and antibacterial effects.However,the protective effects of OAE on intestinal health in broilers and the underlying mechanism remain unclear.This study aimed to investigate the potential effects of OAE on growth performance,the gut microbiota and intestinal health.A total of 8401-d-old male and female broilers(Arbor Acres)were randomly allocated into 6 groups as follows:basal diet(Con),Con+antibiotics(Anti,colistin sulfate 7 g/kg,roxarsone 35 g/kg),Con+400,500,600 and 700 mg/kg OAE(OAE400,OAE500,OAE600 and OAE700).Subse-quently,fermentation in vitro together with oral administration trials were carried out to further assess the function of OAE on intestinal health of broilers.Results Dietary 700 mg/kg OAE supplementation resulted in an increase(P<0.05)in body weight and a decrease(P<0.05)in feed conversion ratio when compared with the control during d 22 to 42 of the trial.OAE addition resulted in lower(P<0.05)jejunal crypt depth and mRNA expression of IL-4 and IL-10 at d 42.In addition,dietary OAE addition increased the abundance of Firmicutes(P=0.087)and Lactobacillus(P<0.05)in the cecum,and increased(P<0.05)the content of acetic acid and butyric acid.In the in vitro fermentation test,OAE significantly increased(P<0.05)the abundance of Lactobacillus,decreased(P<0.05)the abundance of unspecified_Enterobacteriaceae,and increased the content of acetic acid(P<0.05).In the oral administration trial,higher(P<0.05)IL-4 expression was found in broilers when oral inoculation with oregano fermentation microorganisms at d 42.And SIgA content in the ileum was significantly increased(P=0.073)when giving OAE fermentation supernatant.Conclusions Dietary OAE addition could maintain intestinal health and improve growth performance through enhancing intestinal mucosal immunity and barrier function mediated by gut microbiota changes.

Rosemary extract improves egg quality by altering gut barrier function,intestinal microbiota and oviductal gene expressions in late-phase laying hens

Background Rosemary extract(RE)has been reported to exert antioxidant property.However,the application of RE in late-phase laying hens on egg quality,intestinal barrier and microbiota,and oviductal function has not been systematically studied.This study was investigated to detect the potential effects of RE on performance,egg quality,serum parameters,intestinal heath,cecal microbiota and metabolism,and oviductal gene expressions in late-phase laying hens.A total of 21065-week-old“Jing Tint 6”laying hens were randomly allocated into five treatments with six replicates and seven birds per replicate and fed basal diet(CON)or basal diet supplemented with chlortetracycline at 50 mg/kg(CTC)or RE at 50 mg/kg(RE50),100 mg/kg(RE100),and 200 mg/kg(RE200).Results Our results showed that RE200 improved(P<0.05)Haugh unit and n-6/n-3 of egg yolk,serum superoxide dismutase(SOD)compared with CON.No significant differences were observed for Haugh unit and n-6/n-3 of egg yolk among CTC,RE50,RE100 and RE200 groups.Compared with CTC and RE50 groups,RE200 increased serum SOD activity on d 28 and 56.Compared with CON,RE supplementation decreased(P<0.05)total cholesterol(TC)level.CTC,RE100 and RE200 decreased(P<0.05)serum interleukin-6(IL-6)content compared with CON.CTC and RE200 increased jejunal m RNA expression of ZO-1 and Occludin compared with CON.The biomarkers of cecal microbiota and metabolite induced by RE 200,including Firmicutes,Eisenbergiella,Paraprevotella,Papillibacter,and butyrate,were closely associated with Haugh unit,n-6/n-3,SOD,IL-6,and TC.PICRUSt2 analysis indicated that RE altered carbohydrate and amino acid metabolism of cecal microbiota and increased butyrate synthesizing enzymes,including 3-oxoacid Co A-transferase and butyrate-acetoacetate Co A-transferase.Moreover,transcriptomic analysis revealed that RE200 improved gene expressions and functional pathways related to immunity and albumen formation in the oviductal magnum.Conclusions Dietary supplementation with 200 mg/kg RE could increase egg quality of late-phase laying hens via modulating intestinal barrier,cecal microbiota and metabolism,and oviductal function.Overall,RE could be used as a promising feed additive to improve egg quality of laying hens at late stage of production.

Effects of creep feeding and supplemental glutamine or glutamine plus glutamate (Aminogut) on pre- and post-weaning growth performance and intestinal health of piglets

Background： Creep feeding is used to stimulate piglet post-weaning feed consumption.L-Glutamine（GLN） is an important source of fuel for intestinal epithelial cells.The objective of this study was to determine the impact of creep feeding and adding GLN or AminoGut（AG;containing glutamine ＋ glutamate） to pre-and post-weaning diets on pig performance and intestinal health.Litters（N = 120） were allotted to four treatments during 14–21 d of lactation： 1） No creep feed（NC,n = 45）;2） creep fed control diet（CFCD,n = 45）;3） creep fed 1% GLN（CFGLN,n = 15）;4） creep fed.88% AG（CFAG,n = 15）.After weaning,the NC and CFCD groups were sub-divided into three groups（n = 15 each）,receiving either a control nursery diet（NC-CD,CFCD-CD） or a diet supplemented with either GLN（NC-GLN,CFCD-GLN） or with AG（NC-AG,CFCD-AG）.Litters that were creep fed with diets containing GLN or AG also were supplemented with those amino acids in the nursery diets（CFGLN-GLN,CFAG-AG）.Glutamine was added at 1% in all three post-weaning diet phases and AG was added at.88% in phase 1 and 2 and at.66% in phase 3.Results： Feed conversion（feed/gain） showed means among treatment means close to significance（P = 0.056） and Tukey＇s test for pairwise mean comparisons showed that Pigs in the CFGLN-GLN group had the best feed conversion（feed/gain） in the first three-week period post-weaning,exceeding（P = 0.044） controls（CFCD-CD） by 34%.The NC-AG group had（P = 0.02） the greatest feed intake in the last three week of the study,exceeding controls（CFCD-CD） by 12%.CFGLN-GLN,CFCD-GLN and sow reared（SR） pigs had the greatest（P = 0.049） villi height exceeding the CFCD-AG group by 18%,20% and 19% respectively.The CFAG-AG group had the deepest（P = 0.001） crypts among all treatments.CFGLN-GLN,CFCD-GLN and SR groups had the greatest（P = 0.001） number of cells proliferating（PCNA） exceeding those in the NC-CD group by 43%,54% and 63% respectively.Sow reared pigs showed the greatest（P = 0.001） intestinal absorption capacity for xylose and mannitol.Conclusion： Supplementation of creep feed and nursery diets with GLN and/or AminoGut in the first three week improved feed conversion possibly due to improved intestinal health.

Effects of different amino acid levels and a carvacrol-thymol blend on growth performance and intestinal health of weaned pigs

Background:Over the past years,antibiotic growth promoter had been restricted in animal husbandry production in many countries because of antimicrobial resistance and foodborne antibiotic residues.However,the problems of poor intestinal health and low growth efficiency of piglets have not been solved completely in an antibiotic-free diet,and it is urgent to explore alternatives to antimicrobial growth promoters.Methods:Here,a total of 532 weaned pigs were assigned to one of 4 treatments,the low amino acid(AA)level diet(d 1 to d 14 is 1.35%,d 15 to d 42 is 1.25%)(Low AA),the low AA level diet supplementation with a carvacrol-thymol blend(50 mg carvacrol and 50 mg thymol/kg of diet)(CB)(Low AA+CB),the high AA level diet(d 1 to d 14 is 1.50%,d 15 to d 42 is 1.40%)(High AA),and the high AA level diet supplementation with a CB(High AA+CB),respectively.Then we measured growth performance and intestinal health indicators of weaned pigs.Results:Results showed that high AA level significantly reduced plasma urea nitrogen,plasma Interleukin-6(IL-6)and fecal lipocalin-2 contents(P<0.05),significantly increased the relative abundance of fecal Lactobacillus and Enterococcus,and had a trend to increase the fecal secretory immunoglobulin A(sIgA)and mucin 2(MUC 2)contents(P<0.05)in piglets,thereby alleviating the diarrhea of piglets and reducing the feed conversion ratio(FCR)of piglets during d 1~14 after weaning.Dietary supplementation with CB significantly increased the activity of plasma antioxidant enzymes T-SOD and GSH-px(P<0.05),while significantly reduced plasma malondialdehyde(MDA),plasma interleukin-1β(IL-1β),plasma endotoxin and D-lactic acid contents(P<0.05).Meanwhile,CB significantly decreased fecal lipocalin-2 contents and the abundance of fecal Escherichia coli(P<0.05).Thus,we hypothesis that dietary supplementation with CB significantly increased the average daily gain(ADG)of piglets(P<0.05)during d 1~14 after weaning through promoting intestinal health.Conclusion:These results suggest that high AA level and dietary supplementation with CB improved the growth performance of weaned pigs in an antibiotic-free diet by improving AA metabolism and intestinal antioxidant capacity.

Digestibility and metabolism of copper in diets for pigs and influence of dietary copper on growth performance,intestinal health,and overall immune status:a review

The current contribution reviews absorption and metabolism of copper(Cu),Cu deficiency,Cu toxicity,Cu bioavailability,and effects of pharmacological levels of Cu on growth performance and intestinal health of pigs.Copper is a micro mineral involved in metabolic reactions including cellular respiration,tissue pigmentation,hemoglobin formation,and connective tissue development.Copper is mostly absorbed in the upper gastrointestinal tract,particularly in the duodenum,but some Cu is absorbed in the stomach.One way to evaluate the efficacy of sources of Cu is to measure relative bioavailability where responses include tissue concentrations of Cu,concentrations of metalloproteins,and enzymatic activity of animals fed test diets containing graded levels of Cu.The requirement for Cu by pigs is 5 to 10 mg/kg diet,however,Cu can be included at growth-promoting levels(i.e.,75 to 250 mg/kg diet)in diets for weanling and growing pigs to reduce post-weaning diarrhea and improve growth performance.The consistently observed improvement in growth performance upon Cu supplementation is likely a result of increases in lipase activity,growth hormone secretion,and expression of genes involved in postabsorptive metabolism of lipids.The growth-promoting effects of dietary Cu have also been attributed to its bacteriostatic and bactericidal properties because Cu may change bacterial populations in the intestine,and thereby reduce inflammation caused by pathogens.However,further research is needed to determine potential interactions between Cu and non-nutritive feed additives(e.g.,enzymes,probiotics,phytobiotics),and the optimum quantity of Cu as well as the optimum duration of feeding supplemental Cu in diets for pigs should be further investigated.These gaps needs to be addressed to maximize inclusion of Cu in diets to improve growth performance while minimizing diseases and mortality.

Review: Effects of Dietary Fiber Levels and Composition on the Intestinal Health of Finishing Pigs

Despite the fact that dietary fiber is predominant in common feedstuff, its level in the diets of monogastrics has seen a proportional increment with the inclusion of co-products. The source and composition of DF could be liable for enormous varieties in their use. A study carried out by scientists proposed that three major components constitute gut health: the diet, the mucosa, and the commensal microbiota. 70% of total body immune cells constitute the gastrointestinal tract of pigs, therefore it is important that it is included when defining intestinal health. Gut health is of substantial importance in the maintenance of growth performance and overall health of monogastrics. The fermentation of DF results in SCFA which enhances mucosal epithelial proliferation and villus height. Nonetheless, supplementing dietary fiber to the diet in moderation may result in an increase in gut size, volume, length and morphological structure of pigs and other non-ruminants. Gut health maintenance exhibits a certain level of complexity and a subtle balance between mucosa, diet, the commensal microflora, including the digestive epithelium and along with mucous overlaying it. The microbial changes of dietary fiber to monosaccharides in the gut include various principal occasions (reactions) intervened by the enzymatic collection of particularized groups from the gut microbiota. Because fermentation is dependent upon source, structure and physio-chemical properties of dietary fiber, it is therefore of great importance to have as much data as possible on various types of dietary fiber and how intestinal health can be enhanced by them. Thus, there is growing evidence that dietary fiber may have prebiotic effects in pigs. In addition, dietary fiber in diets improves pigs well-being by increasing satiety, influencing behaviour and improving overall health. This review aims to shed more light on the dietary fiber levels and composition on the intestinal health of finishing pigs.

Role of milk carbohydrates in intestinal health of nursery pigs: a review

Intestinal health is essential for the resistance to enteric diseases and for nutrient digestion and absorption to support growth.The intestine of nursery pigs are immature and vulnerable to external challenges,which cause negative impacts on the structure and function of the intestine.Among nutritional interventions,the benefits of milk are significant for the intestinal health of pigs.Milk coproducts have traditionally been used in starter feeds to improve the growth of nursery pigs,but their use is somewhat limited due to the high costs and potential risks of excessive lactose on the intestine.Thus,understanding a proper feeding level of milk carbohydrates is an important start of the feeding strategy.For nursery pigs,lactose is considered a highly digestible energy source compared with plant-based starch,whereas milk oligosaccharides are considered bioactive compounds modulating intestinal immunity and microbiota.Therefore,milk carbohydrates,mainly composed of lactose and oligosaccharides,have essential roles in the intestinal development and functions of nursery pigs.The proper feeding levels of lactose in starter feeds could be variable by weaning age,body weight,or genetic lines.Effects of lactose and milk oligosaccharides have been broadly studied in human health and animal production.Therefore,this review focuses on the mechanisms of lactose and milk oligosaccharides affecting intestinal maturation and functions through modulation of enterocyte proliferation,intestinal immunity,and intestinal microbiota of nursery pigs.

The prevention role of Spirulina platensis(Arthrospira platensis)on intestinal health

Spirulina is a popular herbal food that has a preventive effect on health.In the study,it aimed to evaluate the effects of different doses of Spirulina platensis(Arthrospira platensis)on the morphological properties of the duodenum of rats,and to assign the effect of Spirulina on the expression of proliferating cell nuclear antigen(PCNA)in the rat duodenum,and thereby to observe the effects on intestinal health.30 male Wistar albino rats were divided into 3 groups for 45 days.The first group was received the basal diet;the second group was given 500 mg/kg Spirulina daily by oral gavage;the third group was given 1000 mg/kg Spirulina daily.The duodenum segments were taken at the end of the trial and processed for histological assay.Although the total mucosa,villus height and villus/cript ratio were found higher in high dose Spirulina,the lower cript depth was detected in same group compared to control and low dose group.A significant increase was observed at high dose compared to the control and low dose group in terms of PCNA expression intensity and proliferation index.Findings suggest that high dose of Spirulina may support the duodenal growth,and thereby intestinal health.

Resveratrol alleviates oxidative stress induced by oxidized soybean oil and improves gut function via changing gut microbiota in weaned piglets

Background Oxidized soybean oil(OSO)has been shown to impair growth and exacerbate inflammation,leading to intestinal barrier injury in animals.Recent evidence suggests important roles for resveratrol(RES)in the promoting growth performance,antioxidant capacity,anti-inflammatory,and regulate intestinal barriers in animals.Therefore,The objectives of this study are to investigate the effects of dietary RES(purity 98%)supplementation on the growth performance,antioxidant capacity,inflammatory state,and intestinal function of weaned piglets challenged with OSO.Methods A total of 28 castrated weaned male piglets with a similar body weight of 10.197 replications per treatment and±0.10 kg were randomly assigned to 4 dietary treatments for 28-d feeding trial with 1 piglet per replicate.Treatments were arranged as a 2×2 factorial with oil type[3%fresh soybean oil(FSO)vs.3%OSO]and dietary RES(0vs.300 mg/kg).Results The results showed that relative to the FSO group,OSO stress tended to decrease the average daily feed intake(ADFI),and decreased the activity levels of lipase,villus/crypt ratio(VCR),the mRNA expression of FABP1,SOD2,IL-10 and ZO-1 in the jejunum,and SOD2,GPX1,occludin and ZO-1 in the colon,the levels of acetic acid in the colonic digesta,whereas up-regulated the mRNA expression of IL-1βand TNF-αin the jejunum(P<0.05).Moreover,dietary supplementation with RES increased ether extract(EE),the activity levels of sucrase,lipase,α-amylase,villus height(VH)and VCR,the mRNA expression of FABP1,SOD2,IL-10 and occludin in the jejunum,and FABP1,PPAR-γ,GPX1,occludin and ZO-1 in the colon,and the abundance of Firmicutes,acetic and propionic acid,but decreased the levels of D-lactic acid in the plasma,the abundance of Bacteroidetes in the colonic digesta of weaned piglets compared to the non-RES group(P<0.05).Meanwhile,in the interaction effect analysis,relative to the OSO group,dietary RES supplementation in the diets supplemented with OSO increased the activity levels of trypsin,VH in the jejunum,the abundance of Actinobacteria,the levels of butyric acid of weaned piglets,but failed to influence the activity levels of trypsin and VH,Actinobacteria abundance,the levels of butyric acid when diets were supplemented with FSO(interaction,P<0.05).Relative to the OSO group,dietary RES supplementation in the diets supplemented with OSO decreased the activity levels of DAO in the plasma of weaned piglets but failed to influence the activity levels of DAO when diets were supplemented with FSO(interaction,P<0.05).Relative to the FSO group,dietary RES supplementation in the diets supplemented with FSO decreased the level of propionic acid,whereas RES supplementation failed to influence the level of propionic acid when the diet was supplemented with OSO(interaction,P<0.01).Conclusions Inclusion of OSO intensified inflammatory states and impaired the intestinal health characteristics of weaned piglets.Dietary RES supplementation improved the antioxidant capacity,anti-inflammatory activity,and intestinal morphology.Further studies showed that the protective effects of RES on gut health could be linked to the decreased abundance of Prevotella_1,Clostridium_sensu_stricto_6,and Prevotellaceae_UCG003 and increased levels of acetic and propionic acid.

Bacteroides-derived isovaleric acid enhances mucosal immunity by facilitating intestinal IgA response in broilers

Background:The interaction between nutrition and immunity plays a vital role in nutrient digestion,absorption,and metabolism during poultry production.Recent studies showed that the gut microbiota contributes to the development of intestinal mucosal immunity.However,the mechanisms by which gut microbes regulate this process remain unclear.Methods:We compared the intestinal mucosal immunity and gut microbiota of Arbor Acre broilers AA(lower mucosal immunity)and Chinese native Wuliang Mountain Black-bone chickens(WLMB)(higher mucosal immunity)using 16S rDNA sequencing,transcriptomic analysis,and immunoglobulin A(IgA)antibody repertoire sequencing.We then combined 16S rDNA sequencing with transcriptomics to identify the key microbes and found that they were positively correlated with IgA production.Next,we transplanted candidate microbes into 1-day-old broiler to explore their role in intestinal mucosal immunity.Finally,we verified the function of candidate microbial metabolites in regulating the immune function of macrophages and the intestinal-epithelial cells(IECs)using in vitro experiments.Results:WLMB performs stronger mucosal immunity than AA,including higher IgA levels,more diverse IgA antibody repertoire,and higher bacterial affinity.Bacteroides was identified as the key microbes related to the intestinal IgA response.Bacteroides transplantation could increase IgA concentration in the duodenal contents by enhancing the expression of IgA,polymeric immunoglobin receptor(PIgR),B cell-activating factor of the TNF family(BAFF),and activation-induced cytidine deaminase(AID)in the duodenum.Additionally,Bacteroides-derived isovaleric acid promoted M2 macrophage polarization of macrophage via mTOR/PPAR-γ/STAT3 signaling pathways and regulated the immunologic function of IECs to produce cytokines,including interleukin(IL)-10,IL-4,BAFF,and transforming growth factor-beta(TGF-β),thus promoting IgA production in B cells by facilitating AID expression.Conclusion:Our study revealed that Bacteroides modulate the intestinal IgA response and maintain gut health in broilers.Bacteroides may be a promising alternative as an immunomodulatory microbial agent for developing nextgeneration probiotics for broiler production.

Effects of arginine replacement with L-citrulline on the arginine/nitric oxide metabolism in chickens:An animal model without urea cycle

Background This study examined the efficacy of L-citrulline supplementation on the arginine/nitric oxide metabolism,and intestinal functions of broilers during arginine deficiency.A total of 288 day-old Arbor Acre broilers were randomly assigned to either an arginine deficient basal diet(NC diet),NC diet+0.50%L-arginine(PC diet),or NC diet+0.50%L-citrulline(NCL diet).Production performance was recorded,and at 21 days old,chickens were euthanized for tissue collection.Results The dietary treatments did not affect the growth performance of broilers(P>0.05),although NC diet increased the plasma alanine aminotransferase,urate,and several amino acids,except arginine(P<0.05).In contrast,NCL diet elevated the arginine and ornithine concentration higher than NC diet,and it increased the plasma citrulline greater than the PC diet(P<0.05).The nitric oxide concentration in the kidney and liver tissues,along with the plasma and liver e NOS activities were promoted by NCL diet higher than PC diet(P<0.05).In the liver,the activities of arginase 1,ASS,and ASL,as well as,the gene expression of i NOS and OTC were induced by PC diet greater than NC diet(P<0.05).In the kidney,the arginase 1,ASS and ASL enzymes were also increased by PC diet significantly higher than the NC and NCL diets.Comparatively,the kidney had higher abundance of n NOS,ASS,ARG2,and OTC genes than the liver tissue(P<0.05).In addition,NCL diet upregulated(P<0.05)the m RNA expression of intestinal nutrient transporters(EAAT3 and PEPT1),tight junction proteins(Claudin 1 and Occludin),and intestinal mucosal defense(MUC2 and p Ig R).The intestinal morphology revealed that both PC and NCL diets improved(P<0.05)the ileal VH/CD ratio and the jejunal VH and VH/CD ratio compared to the NC fed broilers.Conclusion This study revealed that NCL diet supported arginine metabolism,nitric oxide synthesis,and promoted the intestinal function of broilers.Thus,L-citrulline may serve as a partial arginine replacement in broiler’s diet without detrimental impacts on the performance,arginine metabolism and gut health of chickens.

Effects of Dietary Vitamin D_(3)on Growth Performance,Immune Status,and Calcium and Phosphorus Metabolism in Litopenaeus vannamei Under Different Salinity Conditions

Vitamin D_(3)(VD_(3)) plays a vital role in various physiological processes in addition to its role in regulating the homeostasis of calcium and phosphorus.The present study was conducted to investigate the effects of dietary VD_(3) on growth performance,immune status and the metabolism of calcium and phosphorus in Litopenaeus vannamei under the optimal salinity(25)and high salinity(35)conditions.Shrimp(2.1 g±0.1 g)were fed with experimental diets containing 0,1500,6000 and 12000IUkg^(−1)VD_(3) for 30 days under two salinity conditions respectively.The results showed that the growth performance and intestinal health were reduced,while oxidative stress was induced in the shrimp cultured at salinity 35 compared to those in the shrimp cultured at salinity 25.Interestingly,dietary supplementation of 1500 IU kg^(−1)VD_(3) at salinity 35 promoted the growth performance,improved the intestinal health,and enhanced the antioxidant capacity and non-specific immunity in shrimp.In addition,the content of inorganic phosphorus in shrimp serum was affected by dietary VD_(3) independent of salinity.In contrast,the expressions of calcium transport-related genes,including calmodulin and Ca2+-ATPase,were regulated by salinity,instead of dietary VD_(3).In conclusion,an appropriate supplementation of dietary VD_(3) under high-salt condition can promote the growth,alleviate intestinal inflammation,enhance antioxidant capacity and immunity,and contribute to phosphorus metabolism in L.vannamei.

Xylanase improves the intestinal barrier function of Nile tilapia(Oreochromis niloticus)fed with soybean(Glycine max)meal

Background Soybean(Glycine max)meal is one of the important protein sources for fish,but the non-starch polysaccharides(NSP)in soybean meal impair the intestinal barrier function.Here we aimed to investigate whether xylanase can alleviate the adverse effects on the gut barrier induced by soybean meal in Nile tilapia and to explore the possible mechanism.Results Nile tilapia(Oreochromis niloticus)(4.09±0.02 g)were fed with two diets including SM(soybean meal)and SMC(soybean meal+3,000 U/kg xylanase)for 8 weeks.We characterized the effects of xylanase on the gut barrier,and the transcriptome analysis was performed to investigate the underlying mechanism.Dietary xylanase improved intestinal morphology and decreased the concentration of lipopolysaccharide(LPS)in serum.The results of transcriptome and Western blotting showed that dietary xylanase up-regulated the expression level of mucin2(MUC2)which may be related to the inhibition of protein kinase RNA-like endoplasmic reticulum kinase(perk)/activating transcription factor 4(atf4)signaling pathways.Microbiome analysis showed that addition of xylanase in soybean meal altered the intestinal microbiota composition and increased the concentration of butyric acid in the gut.Notably,dietary sodium butyrate was supplemented into the soybean meal diet to feed Nile tilapia,and the data verified that sodium butyrate mirrored the beneficial effects of xylanase.Conclusions Collectively,supplementation of xylanase in soybean meal altered the intestinal microbiota composition and increased the content of butyric acid which can repress the perk/atf4 signaling pathway and increase the expression of muc2 to enhance the gut barrier function of Nile tilapia.The present study reveals the mechanism by which xylanase improves the intestinal barrier,and it also provides a theoretical basis for the application of xylanase in aquaculture.

Dietary seaweed-derived polysaccharides improve growth performance of weaned pigs through maintaining intestinal barrier function and modulating gut microbial populations

Background:Seaweed-derived polysaccharides(SDP)represent an attractive source of prebiotic nutraceuticals for the food and animal husbandry industry.However,the mechanism by which SDP from Enteromorpha mediates pig growth are not fully understood.This study aimed to investigate how SDP supplementation influences the growth performance and intestinal health in weaned pigs.Results:In Exp.1,240 weaned pigs were randomly assigned to four dietary treatments and fed with a basal diet or a basal diet containing 200,400 or 800 mg/kg SDP,respectively,in a 21-day trial.Pigs on the 400 or 800 mg/kg SDP-supplemented group had greater ADG and lower F/G ratio than those on the control group(P<0.05).In Exp.2,20 male weaned pigs were randomly assigned to two treatments and fed with a basal diet(CON group)or a basal diet supplemented with 400 mg/kg SDP(the optimum does from Exp.1),in a 21-day trial.Pigs fed the SDP diet had greater ADG,the concentrations of serum IL-6 and TNF-αand the activities of glutathione peroxidase,superoxide dismutase and catalase(P<0.05),and lower F/G,diarrhea rate,as well as serum D-lactate concentrations and diamine oxidase activity(P<0.05).Moreover,dietary SDP supplementation enhanced secretory immunoglobulin A content,villus height and villous height:crypt depth ratio in small intestine,as well as the lactase and maltase activities in jejunum mucosa(P<0.05).SDP supplementation elevated the mRNA levels of inflammatory responserelated genes(IL-6,TNF-α,TLR4,TLR6 and MyD88),and the mRNA and protein levels of ZO-1,claudin-1 and occludin in jejunum mucosa(P<0.05).Importantly,SDP not only increased the Lactobacillus population but also reduced the Escherichia coli population in cecum(P<0.05).Furthermore,SDP increased acetic acid and butyric acid concentrations in cecum(P<0.05).Conclusions:These results not only suggest a beneficial effect of SDP on growth performance and intestinal barrier functions,but also offer potential mechanisms behind SDP-facilitated intestinal health in weaned pigs.

Effect of yeast Saccharomyces cerevisiae supplementation on serum antioxidant capacity, mucosal sIgA secretions and gut microbial populations in weaned piglets

This study was conducted to determine the effect of different forms of yeasts Saccharomyces cerevisiae supplementation on serum antioxidant capacity, mucosal secretory immunoglobulin A（s Ig A） secretions and gut microbial populations in weaned piglets. A total of 96 piglets weaned at 14 d of age were randomly allotted to 4 dietary treatments：（1） basal diet without yeast（Control）;（2） basal diet supplemented with 3.00 g kg–1 live yeast（LY）;（3） basal diet supplemented with 2.66 g kg–1 heat-killed whole yeast（HKY）; and（4） basal diet supplemented with 3.00 g kg–1 superfine yeast powders（SFY）. Each treatment had 4 replicates（pens）, with 6 piglets per replicate. The experiment lasted for 3 wk. At d 7 and 21 of the experiment, the samples of serum, mucosa and mesenteric lymph node（MLN） from jejunum, and digesta from the ileum and cecum were collected for determinations. Compared with the Control, dietary SFY supplementation increased serum superoxide dismutase（SOD） activity and lysozyme levels at d 7, and jejunum mucosal s Ig A secretions at d 21 of the experiment（P〈0.05）. Dietary LY supplementation increased serum SOD activity and jejunum mucosal s Ig A secretions, but decreased serum malondialdehyde（MDA） concentration at d 7 and 21（P〈0.05）. Piglets fed diets supplemented with LY and SFY had lower p H values and decreased numbers of Escherichia coli in the ileum and cecum contents at d 21 compared with the Control（P〈0.05）. Moreover, the ratio of Lactobacilli to E. coli in the ileum and cecum contents was increased by dietary LY and SFY supplementations（P〈0.05）. Collectively, different forms of yeasts, especially LY and SFY, may modulate body antioxidant capacity and enhance the intestinal immunity by regulation of secretions of mucosal s Ig A and reduction of pathogenic bacteria colonization, thus improving intestinal health of weaned piglets.

Dietary Litsea cubeba essential oil supplementation improves growth performance and intestinal health of weaned piglets

This paper was to determine the effects of dietary Litsea cubeba essential oil(LEO)supplementation on growth performance,immune function,antioxidant level,intestinal morphology and microbial composition in weaned piglets.One hundred and ninety-two piglets(Duroc×[Large White×Landrace])with 6.85±0.22 kg mean body weight weaned at 21 d of age were randomly assigned to 4 treatment groups with 8 replicates and were fed with a basal diet(CON)or CON diet containing 100(LLEO),200(MLEO)and 400(HLEO)mg/kg LEO.The results revealed that HLEO supplementation(P<0.05)increased the average daily gain on d 28 compared with CON.MLEO and HLEO supplementation decreased(P<0.05)feed conversion ratio.LEO-containing diets had a lower(P<0.05)diarrhea rate.Supple-mentation with HLEO increased(P<0.05)total antioxidant capacity(T-AOC)both in the serum and liver.Meanwhile,the supplementation of MLEO and HLEO resulted in higher(P<0.05)glutathione peroxidase(GPx)activities both in serum and liver.Supplementation of HLEO increased(P<0.05)serum immu-noglobulin A,immunoglobulin G and interleukin-10,whereas supplementation with MLEO and HLEO decreased(P<0.05)tumor necrosis factor-α.Villus height in the duodenum or jejunum was increased(P<0.05)in the HLEO group,and the villus height to crypt depth ratio in the jejunum was also improved(P<0.05)in the MLEO group.The addition of LEO increased(P<0.05)the richness and diversity of the microbial community in the cecum,which mainly increased the relative abundance of Oscillospir-aceae_UCG-005,Faecalibacterium,Blautia and Coprococcus.Piglets supplemented with HLEO increased(P<0.05)the concentration of short chain fatty acids(SCFA),including acetic acid in the cecum and propionic acid in the colon.In conclusion,these findings indicated that LEO supplementation improved growth performance and intestinal health in weaned piglets.

Exopolysaccharides from lactic acid bacteria,as an alternative to antibiotics,on regulation of intestinal health and the immune system

Over-use or misuse of antibiotics in livestock and poultry production contributes to the rising threat of antibiotic resistance in animals and has negative ecological effects.Exopolysaccharides from lactic acid bacteria(LAB-EPS)are a class of biological macromolecules which are secreted by lactic acid bacteria to the outside of the cell wall during their growth and metabolism.Numerous studies demonstrated that LAB-EPS have anti-inflammatory and antimicrobial activities and are able to regulate intestinal health and the immune system in livestock.They are biodegradable,nontoxic and bio-compatible,which are considered as ideal alternatives to antibiotics.This review aims to discuss and summarize recent research findings of LAB-EPS on regulation of intestinal health and the immune system in animals,and thus provide scientific justification for commercial applications of LAB-EPS in livestock.