Phytogenic feed additives alleviate pathogenic Escherichia coli-induced intestinal damage through improving barrier integrity and inhibiting inflammation in weaned pigs

Background:This study was conducted to investigate the effects of each phytogenic feed additive(PFA;PFA1,bitter citrus extract;PFA2,a microencapsulated blend of thymol and carvacrol;PFA3,a mixture of bitter citrus extract,thymol,and carvacrol;PFA4,a premixture of grape seed,grape marc extract,green tea,and hops;PFA5,fenugreek seed powder)on the growth performance,nutrient digestibility,intestinal morphology,and immune response in weaned pigs infected with Escherichia coli(E.coli).Results:A total of 634-week-old weaned pigs were placed in individual metabolic cages and assigned to seven treatment groups.The seven treatments were as follows:1)NC;basal diet without E.coli challenge,2)PC;basal diet with E.coli challenge,3)T1;PC+0.04%PFA1,4)T2;PC+0.01%PFA2,5)T3;PC+0.10%PFA3,6)T4;PC+0.04%PFA4,7)T5;PC+0.10%PFA5.The experiments lasted in 21 d,including 7 d before and 14 d after the first E.coli challenge.In the E.coli challenge treatments,all pigs were orally inoculated by dividing a total of 10 mL of E.coli F18 for 3 consecutive days.The PFA-added groups significantly increased(P<0.05)average daily gain and feed efficiency and decreased(P<0.05)the fecal score at d 0 to 14 post-inoculation(PI).Tumor necrosis factorαwas significantly lower(P<0.05)in the PFA-added groups except for T1 in d 14 PI compared to the PC treatment.The T3 had a higher(P<0.05)immunoglobulin G and immunoglobulin A concentration compared to the PC treatment at d 7 PI.Also,T3 showed significantly higher(P<0.05)villus height:crypt depth and claudin 1 expression in ileal mucosa,and significantly downregulated(P<0.05)the expression of calprotectin compared to the PC treatment.Conclusions:Supplementation of PFA in weaned pigs challenged with E.coli alleviated the negative effects of E.coli and improved growth performance.Among them,the mixed additive of bitter citrus extract,thymol,and carvacrol showed the most effective results,improving immune response,intestinal morphology,and expression of tight junctions.

Embelin alleviates weaned piglets intestinal inflammation and barrier dysfunction via PCAF/NF-κB signaling pathway in intestinal epithelial cells

Background:Intestinal barrier plays key roles in maintaining intestinal homeostasis.Inflammation damage can severely destroy the intestinal integrity of mammals.This study was conducted to investigate the protective effects of embelin and its molecular mechanisms on intestinal inflammation in a porcine model.One hundred sixty 21-day-old castrated weaned pigs(Duroc×Landrace×Yorkshire,average initial body weight was 7.05 d to four groups and fed with a basal diet o±0.28 kg,equal numbers of castrated males and females)were allotter a basal diet containing 200,400,or 600 mg embelin/kg for 28 d.The growth performance,intestinal inflammatory cytokines,morphology of jejunum and ileum,tight junctions in the intestinal mucosa of piglets were tested.IPEC-1 cells with overexpression of P300/CBP associating factor(PCAF)were treated with embelin,the activity of PCAF and acetylation of nuclear factor-κB(NF-κB)were analyzed to determine the effect of embelin on PCAF/NF-κB pathway in vitro.Results:The results showed that embelin decreased(P<0.05)serum D-lactate and diamine oxidase(DAO)levels,and enhanced the expression of ZO-1,occludin and claudin-1 protein in jejunum and ileum.Moreover,the expression levels of critical inflammation molecules(interleukin-1β,interleukin-6,tumor necrosis factor-α,and NF-κB)were downregulated(P<0.05)by embelin in jejunal and ileal mucosa.Meanwhile,the activity of PCAF were down-regulated(P<0.05)by embelin.Importantly,transfection of PCAF siRNAs to IPEC-1 cell decreased NF-κB activities;embelin treatment downregulated(P<0.05)the acetylation and activities of NF-κB by 31.7%-74.6%in IPEC-1 cells with overexpression of PCAF.Conclusions:These results suggested that embelin ameliorates intestinal inflammation in weaned pigs,which might be mediated by suppressing the PCAF/NF-κB signaling pathway.

Alginate oligosaccharide-induced intestinal morphology, barrier function and epithelium apoptosis modifications have beneficial effects on the growth performance of weaned pigs

Background: Alginate oligosaccharide(AOS), produced from alginate by alginate lyase-mediated depolymerisation, is a potential substitute for antibiotics and possesses growth-enhancing effects. Nevertheless, the mechanisms by which AOS regulates porcine growth remain to be elucidated. Therefore, we investigated the AOS-mediated changes in the growth performance of weaned pigs by determining the intestinal morphology, barrier function,as well as epithelium apoptosis.Methods: Twenty-four weaned pigs were distributed into two groups(n = 12) and received either a basal diet(control group) or the same diet supplemented with 100 mg/kg AOS. On d 15, D-xylose(0.1 g/kg body weight)was orally administrated to eight randomly selected pigs per treatment, and their serum and intestinal mucosa samples were collected 1 h later.Results: Our results showed that inclusion of AOS in the diet for 2 wk increased(P < 0.05) the average daily body weight gain in weaned pigs. Notably, AOS supplementation ameliorated the intestinal morphology and barrier function, as suggested by the enhanced(P < 0.05) intestinal villus height, secretory immunoglobulin A content and goblet cell counts. Compared to the control group, AOS ingestion both decreased(P < 0.05) the total apoptotic percentage and increased(P < 0.05) the proportion of S phase in the intestinal epithelial cells. Furthermore, AOS not only up-regulated(P < 0.05) the B-cell lymphoma-2(BCL2) transcriptional level but also down-regulated(P < 0.05) the B-cell lymphoma-2-associated X protein(BAX), cysteinyl aspartate-specific proteinase-3(caspase-3) and caspase-9 transcriptional levels in the small intestine.Conclusions: In summary, this study provides evidence that supplemental AOS beneficially affects the growth performance of weaned pigs, which may result from the improved intestinal morphology and barrier function,as well as the inhibited enterocyte death, through reducing apoptosis via mitochondria-dependent apoptosis.

Lentinan administration alleviates diarrhea of rotavirus-infected weaned pigs via regulating intestinal immunity

Background:Lentinan(LNT)may regulate many important physiological functions of human and animals.This study aimed to verify whether LNT administration could relieve diarrhea via improving gut immunity in rotavirus(RV)-challenged weaned pigs.Methods:Twenty-eight weaned pigs were randomly fed 2 diets containing 0 or 84 mg/kg LNT product for 19 d(n=14).RV infection was executed on d 15.After extracting polysaccharides from LNT product,its major monosaccharides were analyzed.Then,LNT polysaccharide was used to administrate RV-infected IPEC-J2 cells.Results:Dietary LNT supplementation supported normal function of piglets even when infected with RV,as reflected by reduced growth performance loss and diarrhea prevalence,and maintained gut immunity(P<0.05).The polysaccharide was isolated from LNT product,which molecular weight was 5303 Da,and major monosaccharides included glucose,arabinose and galactose.In RV-infected IPEC-J2 cells,this polysaccharide significantly increased cell viability(P<0.05),and significantly increased anti-virus immunity via regulating pattern recognition receptors and host defense peptides(P<0.05).Conclusion:Those results suggest that LNT administration increases the piglets’resistance to RV-induced stress,likely by supporting intestinal immunity.

Effect of sialyllactose on growth performance and intestinal epithelium functions in weaned pigs challenged by enterotoxigenic Escherichia Coli

Background:Sialyllactose(SL)is one of the most abundant oligosaccharides present in porcine breast milk.However,little is known about its effect on growth performance and intestinal health in weaned pigs.This study was conducted to explore the protective effect of SL on intestinal epithelium in weaned pigs upon enterotoxigenic Escherichia coli(ETEC)challenge.Methods:Thirty-two pigs were randomly divided into four treatments.Pigs fed with a basal diet or basal diet containing SL(5.0 g/kg)were orally infused with ETEC or culture medium.Results:SL supplementation elevated the average daily gain(ADG)and feed efficiency in the ETEC-challenged pigs(P<0.05).SL also improved the digestibilities of dry matter(DM),gross energy(GE),and ash in non-challenged pigs(P<0.05).Moreover,SL not only elevated serum concentrations of immunoglobulins(IgA,IgG,and IgM),but also significantly decreased the serum concentrations of inflammatory cytokines(TNF-α,IL-1β,and IL-6)upon ETEC challenge(P<0.05).Interestingly,SL increased the villus height,the ratio of villus height to crypt depth(V:C),and the activities of mucosal sucrase and maltase in the jejunum and ileum(P<0.05).SL also elevated the concentrations of microbial metabolites(e.g.acetic acid,propanoic acid,and butyric acid)and the abundance of Lactobacillus,Bifidobacterium,and Bacillus in the cecum(P<0.05).Importantly,SL significantly elevated the expression levels of jejunal zonula occludins-1(ZO-1),occluding,and fatty acid transport protein-4(FATP4)in the ETEC-challenged pigs(P<0.05).Conclusions:SL can alleviate inflammation and intestinal injury in weaned pigs upon ETEC challenge,which was associated with suppressed secretion of inflammatory cytokines and elevated serum immunoglobulins,as well as improved intestinal epithelium functions and microbiota.

Pyrroloquinoline quinone regulates the redox status in vitro and in vivo of weaned pigs via the Nrf2/HO-1 pathway

Background:Oxidative stress is a main cause of piglet gut damage and diarrhea.Pyrroloquinoline quinone(PQQ),is a novel redox cofactor with antioxidant properties.However,the effect and mechanism that PQQ supplementation decreases oxidative injury in weaned pigs is not understood.Therefore,the aim of this study is to confirm the effect of PQQ on regulating redox status in weaned pigs and the mechanism for antioxidant function by porcine intestinal epithelial cell line(IPEC-J2)challenged with H_(2)O_(2).Results:Experiment 1,144 Duroc×Landrace×Yorkshire pigs(weaned at 28 d)were allocated to four groups:received a basal diet(control)and diets supplemented with 0.15%,0.30%and 0.45%PQQ,respectively.On d 28,growth performance,diarrhea incidence and redox factors were measured.Experiment 2,IPEC-J2 were treated with or without PQQ in the presence or absence of H_(2)O_(2)for indicated time points.Experiment 3,IPEC-J2 were transfected with or without Nrf2 siRNA,then treated according to Experiment 2.The cell viability,redox factors,protein of tight junctions and Nrf2 pathway were determined.In vivo,PQQ supplementation demonstrated dose-related improvements in average daily gain,and gain to feed ratio(Linear P<0.05).During d 0–28,compared to controls,0.45%PQQ supplementation for pigs decreased diarrhea incidence and MDA content in liver and jejunum,and increased concentration of SOD in liver;0.3%PQQ supplementation decreased ileal and liver MDA concentration;and 0.15%PQQ supplementation decreased ileal MDA concentration(P<0.05).In vitro,compared to cells cultured with H_(2)O_(2),pre-treatment with PQQ increased cell viability,tight junction proteins expression including ZO-1,ZO-2,Occludin and Claudin-1;and decreased ROS concentration and level of Caspase-3(P<0.05);as well as upregulated the ratio of Bcl-2 to Bax and protein expression of nuclear Nrf2,HO-1.Notably,Nrf2 knockdown by transfection with Nrf2 siRNA largely abrogated the positive effects of PQQ pretreatment on H_(2)O_(2)-induced intracellular changes.Conclusions:PQQ administration attenuated oxidative stress in weaned pigs which is associated with activation of Nrf2/HO-1 pathway.

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.

Dietary Bacillus spp.enhanced growth and disease resistance of weaned pigs by modulating intestinal microbiota and systemic immunity

Background:Previous research has shown that dietary supplementation of Bacillus spp.probiotics exerts beneficial effects on animals’growth.However,limited studies have evaluated the efficacy of Bacillus spp.on weaned pigs and their effects on host gut health and microbiome,and systemic immunity using a disease challenge model.The objective of this experiment was to investigate the effects of two Bacillus spp.strains(Bacillus subtilis DSM 32540 and Bacillus pumilus DSM 32539)on growth performance,diarrhea,intestinal health,microbiome,and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli(ETEC).Results:Pigs in PRO1(Bacillus subtilis DSM 32540)had greater(P<0.05)body weight on d 7 and 14 PI,greater(P<0.05)ADG from d 0 to 7 and d 7 to 14 PI,compared with pigs in CON(Control).Pigs in PRO1 had milder(P<0.05)diarrhea on d 2 and 3 PI compared with pigs in CON.However,no differences were observed in growth performance and diarrhea score between PRO2(Bacillus pumilus DSM 32539)and CON groups.Supplementation of PRO1 decreased(P<0.05)lymphocyte counts on d 7 and 14 PI,compared with CON.Supplementation of PRO1 and PRO2 both reduced(P<0.05)total coliforms in mesenteric lymph nodes on d 21 PI.Pigs in PRO2 had greater(P<0.05)goblet cell number and sulfomucin percentage in duodenal villi and greater(P<0.05)sialomucin percentage in jejunal villi than pigs in CON.Supplementation of PRO1 up-regulated(P<0.05)MUC2 gene expression in jejunal mucosa and reduced(P<0.05)PTGS-2 and IL1B gene expression in ileal mucosa on d 21 PI,compared with CON.Pigs in PRO1 had reduced(P<0.05)relative abundance of families Lachnospiraceae,Peptostreptococcaceae and Pasteurellaceae in the ileum.Conclusions:Supplementation of Bacillus subtilis DSM 32540 improved growth performance,alleviated diarrhea severity,enhanced gut health,and reduced systemic inflammation of weaned pigs infected with ETEC F18.Although Bacillus pumilus DSM 32539 was able to alleviate systemic inflammation,it had limited impacts on growth performance and severity of diarrhea of ETEC F18 challenged weaned pigs.

Effects of dietary tributyrin on intestinal mucosa development,mitochondrial function and AMPK-mTOR pathway in weaned pigs

Background:The objective of this experiment was to investigate the influence of dietary tributyrin on intestinal mucosa development,oxidative stress,mitochondrial function and AMPK-mTOR signaling pathway.Methods:Seventy-two pigs were divided into two treatments and received either a basal diet or the same diet supplemented with 750 mg/kg tributyrin.Each treatment has six replicates of six pigs.After 14 days,6 pigs from each treatment were selected and the jejunal samples were collected.Results:Results showed that supplemental tributyrin increased(P<0.05)villus height and villus height:crypt depth of weaned pigs.Pigs fed tributyrin had greater(P<0.05)RNA/DNA and protein/DNA ratios than pigs on the control group.The mRNA levels of sodium glucose transport protein-1 and glucose transporter-2 in the jejunum were upregulated(P<0.05)in pigs fed the tributyrin diet.Dietary tributyrin supplementation lowered(P<0.05)the malondialdehyde and hydrogen peroxide(H2O2)content in jejunum,enhanced(P<0.05)the mitochondrial function,as demonstrated by decreased(P<0.05)reactive oxygen species level and increased(P<0.05)mitochondrial membrane potential.Furthermore,tributyrin increased(P<0.05)mitochondrial DNA content and the mRNA abundance of genes related to mitochondrial functions,including peroxisomal proliferator-activated receptor-γcoactivator-1α,mitochondrial transcription factor A,nuclear respiratory factor-1 in the jejunum.Supplementation with tributyrin elevated(P<0.05)the phosphorylation level of AMPK and inhibited(P<0.05)the phosphorylation level of mTOR in jejunum compared with the control group.Conclusions:These findings suggest that dietary supplementation with tributyrin promotes intestinal mucosa growth,extenuates oxidative stress,improves mitochondrial function and modulates the AMPK-mTOR signal pathway of weaned pigs.

Trace amounts of antibiotic altered metabolomic and microbial profiles of weaned pigs infected with a pathogenic E.coli

Background:Our previous study has shown that supplementation of trace amounts of antibiotic exacerbated the detrimental effects of enterotoxigenic E.coli(ETEC)infection and delayed the recovery of pigs that may be associated with modified metabolites and metabolic pathways.Therefore,the objective of this study was to explore the impacts of trace levels of antibiotic(carbadox)on host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results:The multivariate analysis highlighted a distinct metabolomic profile of serum and colon digesta between trace amounts of antibiotic(TRA;0.5 mg/kg carbadox)and label-recommended dose antibiotic(REC;50 mg/kg carbadox)on d 5 post-inoculation(PI).The relative abundance of metabolomic markers of amino acids,carbohydrates,and purine metabolism were significantly differentiated between the TRA and REC groups(q<0.2).In addition,pigs in REC group had the highest(P<0.05)relative abundance of Lactobacillaceae and tended to have increased(P<0.10)relative abundance of Lachnospiraceae in the colon digesta on d 5 PI.On d 11 PI,pigs in REC had greater(P<0.05)relative abundance of Clostridiaceae compared with other groups,whereas had reduced(P<0.05)relative abundance of Prevotellaceae than pigs in control group.Conclusions:Trace amounts of antibiotic resulted in differential metabolites and metabolic pathways that may be associated with its slow responses against ETEC F18 infection.The altered gut microbiota profiles by labelrecommended dose antibiotic may contribute to the promotion of disease resistance in weaned pigs.

Supplementation of oligosaccharide-based polymer enhanced growth and disease resistance of weaned pigs by modulating intestinal integrity and systemic immunity

Background:There is a great demand for antibiotic alternatives to maintain animal health and productivity.The objective of this experiment was to determine the efficacy of dietary supplementation of a blood group A6 type 1antigen oligosaccharides-based polymer(Coligo)on growth performance,diarrhea severity,intestinal health,and systemic immunity of weaned pigs experimentally infected with an enterotoxigenic Escherichia coli(ETEC),when compared with antibiotics.Results:Pigs in antibiotic carbadox or Coligo treatment groups had greater(P<0.05)body weight on d 5 or d 11post-inoculation(PI)than pigs in the control group,respectively.Supplementation of antibiotics or Coligo enhanced(P<0.05)feed efficiency from d 0 to 5 PI and reduced(P<0.05)frequency of diarrhea throughout the experiment,compared with pigs in the control group.Supplementation of antibiotics reduced(P<0.05)fecalβ-hemolytic coliforms on d 2,5,and 8 PI.Pigs in antibiotics or Coligo groups had reduced(P<0.05)neutrophil counts and serum haptoglobin concentration compared to pigs in the control group on d 2 and 5 PI.Pigs in Coligo had reduced(P<0.05)total coliforms in mesenteric lymph nodes on d 5 and 11 PI,whereas pigs in antibiotics or Coligo groups had reduced(P<0.05)total coliforms in spleen on d 11 PI compared with pigs in the control group.On d 5 PI,pigs in the Coligo group had greater(P<0.05)gene expression of ZO1 in jejunal mucosa,but less(P<0.05)m RNA expression of IL1B,IL6,and TNF in ileal mucosa,in comparison with pigs in the control group.Supplementation of antibiotics enhanced(P<0.05)the gene expression of OCLN in jejunal mucosa but decreased(P<0.05)IL1B and IL6 gene expression in ileal mucosa,compared with the control.On d 11 PI,supplementation of antibiotics or Coligo up-regulated(P<0.05)gene expression of CLDN1 in jejunal mucosa,but Coligo reduced(P<0.05)IL6 gene expression in ileal mucosa compared to pigs in the control group.Conclusions:Supplementation of Coligo improved growth performance,alleviated diarrhea severity,and enhanced gut health in weaned pigs infected with ETEC F18 in a manner similar to in-feed antibiotics.

Effects of Xylanase and Protease Supplementation on Nutrient Digestibility in Diets Based on Peas and Wheat Fed to Weaned Pigs

This experiment was conducted to determine the effects of a commercial enzyme mixture providing xylanase and protease activities on the digestibility of dietary nutrients when added to diets based on peas and wheat and fed to 9. 5 to 15 kg pigs. Pigs were weaned at 18 to 21 days of age and fitted with a simple T-cannula at the distal ileum,6 to 7 days after weaning. After 5 to 7 days for adaptation to their diets, ileal digesta, and feces were collected. Enzyme supplementation had no effect on the apparent ileal or fecal digestibility of any dietary nutrient. There was a numerical improvement （ P 〉 0.05 ） in the ileal digestibility of fiber. In conclusion, xylanase and protease appeared to be ineffective in improving nutrient digestibility when supplemented in diets based on peas and wheat fed to weaned pigs.

Impact of an oligosaccharide-based polymer on the metabolic profiles and microbial ecology of weanling pigs experimentally infected with a pathogenic E.coli

Background Our previous study has reported that supplementation of oligosaccharide-based polymer enhances gut health and disease resistance of pigs infected with enterotoxigenic E.coli(ETEC)F18 in a manner similar to carbadox.The objective of this study was to investigate the impacts of oligosaccharide-based polymer or antibiotic on the host metabolic profiles and colon microbiota of weaned pigs experimentally infected with ETEC F18.Results Multivariate analysis highlighted the differences in the metabolic profiles of serum and colon digesta which were predominantly found between pigs supplemented with oligosaccharide-based polymer and antibiotic.The relative abundance of metabolic markers of immune responses and nutrient metabolisms,such as amino acids and carbohydrates,were significantly differentiated between the oligosaccharide-based polymer and antibiotic groups(q<0.2 and fold change>2.0).In addition,pigs in antibiotic had a reduced(P<0.05)relative abundance of Lachnospiraceae and Lactobacillaceae,whereas had greater(P<0.05)Clostridiaceae and Streptococcaceae in the colon digesta on d 11 post-inoculation(PI)compared with d 5 PI.Conclusions The impact of oligosaccharide-based polymer on the metabolic and microbial profiles of pigs is not fully understood,and further exploration is needed.However,current research suggest that various mechanisms are involved in the enhanced disease resistance and performance in ETEC-challenged pigs by supplementing this polymer.

Natural capsicum extract replacing chlortetracycline enhances performance via improving digestive enzyme activities,antioxidant capacity,anti-inflammatory function,and gut health in weaned pigs

The objective of this study was to investigate the effects of natural capsicum extract(NCE,containing 2%natural capsaicin,the rest is carrier)replacing chlortetracycline(CTC)on performance,digestive enzyme activities,antioxidant capacity,inflammatory cytokines,and gut health in weaned pigs.A total of 108 weaned pigs(Duroc×[Landrace×Yorkshire],initial body weight-8.68±1.34 kg;weaned on d 28)were randomly allotted into 3 treatments with 6 replicate pens per treatment(3 barrows and 3 gilts per pen).The treatments include a corn-soybean meal basal diet as a control group(CON),a CTC group(basal diet+CTC at 75 mg/kg),and a NCE group(basal diet--NEC at 80 mg/kg).Compared with CON and CTC,NCE had increased(P<0.05)average daily gain in phase 2(d 15 to 28)and overall(d 1 to 28),and higher(P<0.05)apparent total tract digestibility of gross energy,dry matter,crude protein,and organic matter in phase 1(d 1 to 14).These pigs also had increased(P<0.05)pancrelipase activity in pancreas,α-amylase,lipase and protease activities in the jejunal mucosa,and lipase activity in the ileal mucosa on d 28.Moreover,NCE had increased(P<0.05)the contents of growth hormone,β-endorphin,5-hydroxytryptamine,total antioxidant capacity,total superoxide dismutase,catalase,and IL-10,as well as decreased(P<0.05)contents of malondialdehyde,tumor nuclear factor-a,interferon-y,and interleukin-6 in serum on d 28 compared with CON and CTC.NCE showed higher(P<0.05)propionic acid,butyric acid and total volatile fatty acids(VFA)contents,and increased(P<0.05)relative abundance of Faecalibacterium in colon,as well as higher(P<0.05)propionic acid and total volatile fatty acids in cecum on d 28 compared with CON.In conclusion,NCE replacing CTC could enhance performance via improving digestive enzyme activities,antioxidant capacity,anti-inflammatory function,gut VFA composition and microbiota community in weaned pigs,and it could be used as a potential target for the development of feed additives.

Effects of dietary supplementation with essential oils and protease on growth performance,antioxidation,inflammation and intestinal function of weaned pigs

This experiment evaluated the impacts of essential oils(EO)and protease(PRO),independently or in combination,on growth performance,antioxidation,inflammation and intestinal function of weaned pigs.One hundred and sixty weaned pigs(21 d of age,BW of 6.74±0.20 kg)were randomly divided into 4 treatments with 8 replicate pens of 5 pigs per pen.Dietary treatments included the following:1)control diet(CON),2)CON with 300 mg/kg essential oils(EO),3)CON with 500 mg/kg protease(PRO),4)CON with 300 mg/kg essential oil and 500 mg/kg protease(EO + PRO).On d 8,one pig from each penwas selected for sampling.The remaining pigs were fed for an additional week and growth performance was monitored during this period.Dietary treatments had no marked effects(P>0.05)on the growth performance of pigs.However,pigs receiving EO diet had higher(P<0.05)serumglutathione peroxidase(GSH-Px)activity,and tended to decrease(P=0.063)serum concentration of tumor necrosis factor-a(TNF-a).In addition,pigs receiving EO diet had higher(P<0.05)abundances of phylum Actinobacteria,and genera Bifidobacterium,and lower(P<0.05)phylum Bacteroidetes and genera Alloprevotella in colonic digesta.Pigs receiving PRO diet decreased(P<0.05)the serum concentration of malondialdehyde(MDA)and diamine oxidase activity,increased(P<0.05)the villus height and the ratio of villus height to crypt depth in duodenum,increased sucrase activity in jejunal mucosa,and also increased the abundance of phylum Actinobacteria in colonic digesta.Furthermore,the synergistic effects of EO and PROwas observed(P<0.05)for pigs with decreasing serum TNF-a concentration and increasing serum GSH-Px activity.Collectively,the results indicated that dietary supplementation of EO and PRO had no significant effects on growth performance of weaned pigs.EO diet appeared to improve antioxidant activity and intestinal microbiota,while PRO diet improved intestinal morphology and digestive enzyme activity,and there was a synergistic effect of EO and PRO on reducing inflammatory parameters in weaned pigs.

Effects of dietary threonine:lysine ratioes and sanitary conditions on performance, plasma urea nitrogen, plasma-free threonine and lysine of weaned pigs

Two 21 d-experiments were conducted to determine the optimum standardized ileal digestible(SID)threonine:lysine ratio(Thr:Lys) for weaned piglets reared under clean(Exp. 1) or unclean(Exp. 2) sanitary conditions and fed antibiotic-free diets. In each experiment, 90 mixed-sex pigs(Duroc × [Yorkshire × Landrace]; initial BW 7.2 ± 0.3 kg) were randomly assigned to 5 dietary treatments each with 6 replicates(3 pigs per pen). The dietary treatments were 5 graded levels of SID Thr:Lys(55,59, 63, 67 and 71%). Diets were corn-wheat-soybean meal-based with a constant SID Lys of 1.18% that was set to be second limiting amino acid. In Exp. 1 and Exp. 2, plasma-free Thr increased(P = 0.05) with increasing dietary SID Thr:Lys. In Exp. 1, the SID Thr:Lys for gain-to-feed ratio(G:F) was optimized at 65%.In Exp. 2, the estimated optimal SID Thr:Lys for overall G:F was 66.5%. In conclusion, an average optimal SID Thr:Lys of 65 and 66.5% could be used to optimize feed efficiency for weaned pigs under clean and unclean sanitary conditions, respectively.

A water-soluble β-glucan improves growth performance by altering gut microbiome and health in weaned pigs

Beta-glucan has been shown to have a beneficial effect on gastrointestinal health.This experiment was conducted to investigate the effects ofβ-glucan isolated from Agrobacterium sp.ZX09 on growth performance and intestinal health of weaning pigs.A total of 108 weaned pigs(21 d of age;6.05±0.36 kg)were randomly divided into 3 groups(6 pens/group;6 pigs/pen),and the groups were each treated with the following diets:1)basal diet,2)basal diet supplemented with 20 mg/kg olaquindox,3)basal diet supplemented with 200 mg/kgβ-glucan,for 21 d.Compared with the control group,pigs fed with200 mg/kgβ-glucan had greaterBW,average daily gain and duodenal villus height to crypt depth ratio(P<0.05).Olaquindox increased the duodenal or jejunal villus height of pigs compared withβ-glucan.Compared with the control group,β-glucan tended to increase the occludin mRNA expression in the jejunum(0.05<P<0.10).Beta-glucan enriched the beneficial microbiota in the ileum of pigs(P<0.05).In conclusion,β-glucan may promote growth performance by improving intestinal health and increasing beneficial microbiota of weaned pigs.The study results will provide valuable theoretical guidance for the utilization ofβ-glucan in weaned pigs.

Dietary plant extracts modulate gene expression profiles in alveolar macrophages of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Background: Our previous study showed that 3 plant extracts enhanced the immune responses and growth efficiency of weaned pigs infected with porcine reproductive and respiratory syndrome virus(PRRSV), which is one of the most economically important disease in swine industry. However, each plant extract differently effected on growth efficiency and immune responses. Therefore, the objective of this study was conducted to characterize the effects and investigate the potential underlying mechanisms of 3 plant extracts on gene expression of alveolar macrophages in weaned pigs experimentally infected with PRRSV.Results: PRRSV infection altered(P < 0.05) the expression of 1,352 genes in pigs fed the control(CON;755 up, 597 down). Compared with the infected CON, feeding capsicum(CAP), garlic botanical(GAR), or turmeric oleoresin(TUR) altered the expression of 46 genes(24 up, 22 down), 134 genes(59 up, 75 down), or 98 genes(55 up, 43 down) in alveolar macrophages of PRRSV-infected pigs, respectively. PRRSV infection up-regulated(P < 0.05) the expression of genes related to cell apoptosis, immune system process, and response to stimulus, but downregulated(P < 0.05) the expression of genes involved in signaling transduction and innate immune response.Compared with the infected CON, feeding TUR or GAR reduced(P < 0.05) the expression of genes associated with antigen processing and presentation, feeding CAP up-regulated(P < 0.05) the expression of genes involved in antigen processing and presentation. Supplementation of CAP, GAR, or TUR also enhanced(P < 0.05) the expression of several genes related to amino acid metabolism, steroid hormone synthesis, or RNA degradation, respectively.Conclusions: The results suggest that 3 plant extracts differently regulated the expression of genes in alveolar macrophages of PRRSV-infected pigs, especially altering genes involved in immunity.

Effects of dietary Selenomethionine supplementation on growth performance,antioxidant status,plasma selenium concentration,and immune function in weaning pigs

Background： This study was designed to evaluate the efficacy of DL-selenomethionine （DL^SeMet） supplementation on growth performance, antioxidant status, plasma selenium （Se） concentration, and immune function of weaning pigs. 216 weaning pigs were randomly allocated to 6 treatments with 6 replicates each according to a complete randomized block design. Each replicate had six pigs. Diet of group one was corn-soybean basal diet without any additional Se supplement. Group 2 was supplemented with 0.3 mg/kg of Se from sodium selenite. Groups 3-6 were supplemented with 0.1, 0.3, 0.5, and 0.7 mg/kg of Se from DL-SeMet, respectively. The trial lasted for 42 days. Results： Pigs supplemented with 0.3 and 0.7 mg/kg DL-SeMet obtained better feed gain ratio （P 〈 0.05）. The best antioxidant ability （serum, liver, and muscle） was shown in 0.1-0.3 mg/kg DL-SeMet groups （P〈 0.05）. The plasma Se concentration increased as the dietary DL-SeMet level elevated. The immunity among groups was not affected. Conclusions： DL-SeMet supplementation in the diet significantly improved the growth performance, antioxidant ability and plasma Se content of weaning pigs. DL-SeMet can replace sodium selenite in the diet of weaning pigs.

Endogenous chitinase might lead to differences in growth performance and intestinal health of piglets fed different levels of black soldier fly larva meal

This study aimed to investigate the effects of different levels of black soldier fly(BSF)replacing soybean meal(SBM)in diets on the performance and health condition of piglets.A total of 180 weaned piglets were allocated into 5 treatments:BSF0(corn-soybean meal basal diet),BSF25(BSF replacing 25%SBM),BSF50(BSF replacing 50%SBM),BSF75(BSF replacing 75%SBM)and BSF100(BSF replacing 100%SBM).During the whole period,in comparison with BSF0,average daily gain(ADG)and average daily feed intake increased in the BSF25 and BSF50 groups,whereas ADG decreased in the BSF75 and BSF100groups(P<0.05).The result of quadratic fitting curve showed that piglets exhibited the highest ADG when BSF replaced around 20%SBM.Compared with BSF0,organic matter and dry matter digestibility improved in the BSF25 group,whereas ether extract digestibility decreased in the BSF100 group(P<0.05).In comparison with BSF0,piglets from the BSF25 group showed a higher duodenal ratio of villus height to crypt depth,increased jejunal sucrase activity,serum neuropeptide Y and ghrelin levels,elevated ileal immunoglobulin(Ig)A,Ig G and Ig M contents and a lower leptin level,and piglets from the BSF100 group exhibited an increased relative weight of kidney(P<0.05).However,no significant differences were observed in the expression level of tight junction proteins and chitin-degrading enzyme.Additionally,compared with BSF0,the abundance of short chain fatty acid producing bacteria such as Ruminococcaceae,Faecalibacterium and Butyricicoccus increased,and potential pathogenic bacteria decreased in piglets from the BSF25 group,whereas piglets from the BSF100 group had a greater abundance of harmful bacteria.In conclusion,BSF replacing 25%SBM in diets could improve digestive parameters,immune function and intestinal microbiota,and thus improved growth performance of piglets.However,BSF replacing 100%SBM showed an adverse effect on piglet performance,and the reason might be related to the limited amount of chitin-degrading enzyme.