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.

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.

The biological stress of early weaned piglets

Pigs experience biological stress such as physiological, environmental, and social challenges when weaned from the sow. The process of weaning is one of the most stressful events in the pig＇s life that can contribute to intestinal and immune system dysfunctions that result in reduced pig health, growth, and feed intake, particularly during the first week after weaning. Technological improvements in housing, nutrition, health, and management have been used to minimize some of the adverse effects of weaning stress, but a greater understanding of the biological impact of stress is needed to improve strategies to overcome weaning stress. The focus of this review paper is to briefly describe how the biological stress associated with weaning impacts intestinal morphology, structure, physiology, and intestinal immune responses that can impact subsequent production efficiencies such as growth, intake, morbidity, and mortality.

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.

Efficacy of medium-chain fatty acid salts distilled from coconut oil against two enteric pathogen challenges in weanling piglets

Background:The search for alternatives to antibiotics in pig production has increased the interest in natural resources with antimicrobial properties,such as medium-chain fatty acids(MCFA)as in-feed additives.This study evaluated the potential of a novel blend of MCFA salts(DIC)from distilled coconut oil with a lauric acid content to reduce enteropathogens and control intestinal diseases around weaning.Two experimental disease models were implemented in early-weaned piglets,consisting of two oral challenges:Salmonella Typhimurium(1.2×10~8 CFU)or enterotoxigenic Escherichia coli(ETEC)F4(1.5×10~9 CFU).The parameters assessed were:animal performance,clinical signs,pathogen excretion,intestinal fermentation,immune-inflammatory response,and intestinal morphology.Results:The Salmonella challenge promoted an acute course of diarrhea,with most of the parameters responding to the challenge,whereas the ETEC F4 challenge promoted a mild clinical course.A consistent antipathogenic effect of DIC was observed in both trials in the hindgut,with reductions in Salmonella spp.plate counts in the cecum(P=0.03)on d 8 post-inoculation(PI)(Salmonella trial),and of enterobacteria and total coliform counts in the ileum and colon(P<0.10)on d 8 PI(ETEC F4 trial).When analyzing the entire colonic microbiota(16 S rRNA gene sequencing),this additive tended(P=0.13)to reduce the Firmicutes/Bacteroidetes ratio and enriched Fibrobacteres after the Salmonella challenge.In the ETEC F4 challenge,DIC prompted structural changes in the ecosystem with increases in Dialister,and a trend(P=0.14)to increase the Veillonellaceae family.Other parameters such as the intestinal fermentation products or serum pro-inflammatory mediators were not modified by DIC supplementation,nor were the histological parameters.Only the intraepithelial lymphocyte(IEL)counts were lowered by DIC in animals challenged with Salmonella(P=0.07).With ETEC F4,the IEL counts were higher with DIC on d 8 PI(P=0.08).Conclusions:This study confirms the potential activity of this MCFA salts mixture to reduce intestinal colonization by opportunistic pathogens such as Salmonella or E.coli and its ability to modulate colonic microbiota.These changes could explain to some extent the local immune cell response at the ileal level.

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.

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 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 supplementation of Bacillus subtilis influenced intestinal health of weaned pigs experimentally infected with a pathogenic E. coli

Background: There is growing evidence to support the beneficial effects of supplementing direct-fed microbials(DFM) on performance, health status, and immune responses of weaned pigs. Therefore, the objective of this study was to investigate dietary supplementation of Bacillus subtilis(DSM 25841) on growth performance, diarrhea, gut permeability and immunity of weaned pigs experimentally infected with a pathogenic F-18 Escherichia coli(E. coli).Results: The F18 E. coli infection reduced(P < 0.05) growth performance and intestinal villi height, whereas increased(P < 0.05) diarrhea and transcellular and paracellular permeability in the jejunum compared with non-challenged control. Supplementation of Bacillus subtilis linearly enhanced average daily gain of E. coli infected pigs from d 0 to 5 post-inoculation(PI)(P < 0.05) and d 0 to 11 PI(P = 0.058). Supplementation of high dose of Bacillus subtilis reduced(P < 0.05) both transcellular and paracellular permeability on d 5 and d11 PI compared with the E. coli infected pigs fed with control diet. E. coli infection up-regulated(P < 0.05)the m RNA expression of SLC5 A10(soluble carrier family 5 member 10) and MUC2(mucin 2) on d 5 PI, but down-regulated(P < 0.05) expression of SLC5 A10, MUC2, and CLDN1 on d 11 PI in jejunal mucosa when pigs were fed with the control diet. Supplementation of Bacillus subtilis linearly up-regulated(P < 0.05) the m RNA expression of CFTR and ZO1 on d 5 PI and SLC5 A10 and MUC2 on d 11 PI in jejunal mucosa of E. coli infected pigs. In addition, E. coli infection increased(P < 0.05) the m RNA expression of several immune genes(IL1 A, IL1 B, and IL7 on d 5 PI, and IL1 B, IL6, IL7, and TNF on d 11 PI) in the ileal mucosa of weaned pigs. Inclusion of Bacillus subtilis to control diet linearly down-regulated gene expression of IL1 A on d 5 PI(P = 0.07) and IL6 on d 11 PI(P < 0.05) in ileal mucosa of E. coli infected pigs.Conclusions: Supplementation of Bacillus subtilis(DSM 25841) enhanced growth rate and improved gut barrier function of weaned pigs experimentally infected with a pathogenic E. coli.

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.

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.

Feed- and feed additives-related aspects of gut health and development in weanling pigs

The development of new/different management and feeding strategies to stimulate gut development and health in newly-weaned pigs, in order to improve growth performance while minimizing the use of antimicrobial compounds such as antibiotic growth promotants （AGP） and heavy mineral compounds, is essential for the long-term sustainability of the pig industry. Factors including the sub-optimal intake of nutrients and energy, inappropriate microbiota biomass and （or） balance, immature and compromised immune function, and psychosomatic factors caused by weaning can compromise both the efficiency of digestion and absorption and intestinal barrier function through mucosal damage and alteration of tight junction integrity. As a consequence, pigs at weaning are highly susceptible to pathogenic enteric conditions such as post-weaning diarrhea that may be caused by serotypes of enterotoxigenic Escherichia coil Many dietary components, e.g., protein, fiber, feed additives and minerals, are known to influence microbial growth in the gastrointestinal tract that in turn can impact upon pig growth and health, although the relationships between these are sometimes not necessarily apparent or obvious. In a world climate of increased scrutiny over the use of antibiotics per se in pig production, certain feed additives are seen as alternatives/replacements to antibiotics, and have evolved in some cases to have important roles in everyday commercial pig nutrition. Nevertheless and in general, there remains inconsistency and variability in the efficacy of some feed additives and in cases of severe disease outbreaks, for example, therapeutic antibiotics and/or heavy minerals such as zinc oxide （ZnO） are generally relied upon. If feed ingredients and （or） feed additives are to be used with greater regularity and reliability, then it is necessary to better understand the mechanisms whereby antibiotics and minerals such as ZnO influence animal physiology, in conjunction with the use of appropriate challenge models and in vitro and in vivo techniques.

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.

Short- and Long-Term Effects of Weaning Age on Pig Innate Immune Status

The study was conducted to evaluate short- and long-term effects of pig wean age on innate immunity and cortisol. Seventy-two white crossbred pigs from 12 litters were randomly assigned to a weaning age of 14 or 28 d-of-age. Pigs were weaned at assigned treatment age and kept as littermates until 20 wk-of-age. Blood samples were taken prior to weaning (d 0) and days 1, 7, and 14 post-weaning (short-term), and at 8, 12, 16, and 20 wk-of-age (long-term). Prior to weaning (d 0), total WBC and lymphocyte numbers were greater for 28-d weaned pigs than 14-d and 28-d pigs had greater lymphocyte numbers at d 1, 7, and 14 post-weaning. At d 0, cytotoxicity and phagocytosis were greater for 14-d than 28-d weaned pigs. Regardless of age, at d 1 and 7 post-weaning all pigs had greater WBC counts, neutrophils, and phagocytosis, but reduced lymphocytes and NK cytotoxicity compared with d 0. Cortisol was decreased at d 7 and increased at d 14 post-weaning in 28-d weaned pigs. These pigs also had greater cortisol at d 0, 1 and 14 post-weaning than 14-d weaned pigs. Effects of weaning on leukocyte profile and N:L ratio were longer-lasting in 14-d weaned pigs than 28-d with effects still apparent at d 14 post-weaning for lymphocytes, neutrophils, N:L ratio, NK, phagocytosis, and IgG. These data imply that weaning age differentially affected pig leukocyte populations and innate immunity in response to weaning stress in both short- and long-term. More specifically, pigs weaned at 14 d-of-age had a more profound and longer-lasting stress response to weaning and 14-d weaned pigs had a more profound innate response, especially NK cytotoxicity while 28-d weaned pigs had more profound antibody response (IgG) in the long-term and these responses were still evident at 20 wk-of-age.

Haematological Traits of Nigerian Indigenous Pig and Its Hybrid (50% Large White ×50 NIP) at Post Weaning Ages

Pigs play a major role in socioeconomic life of the people;it serves as a source of income for rural population and fulfill important role in culture and food security. Fifty-one weaners were randomly selected at 9, 17 and 25 weeks of age for analysis. Blood from the jugular vein of the weaners was taken to the laboratory for analysis. The leaukocyte parameters used for this study were White blood cell count (WBC), Lymphocyte (LYM) count, Neutrophil (NEU) count, Eosinophil (EOS) and Monocyte (MON) count) and Platelet (PLT) count. Data collected on these leaukocyte parameters were subjected to Analysis of Variance (ANOVA) while the means were separated using Duncan’s Multiple Range Test. The results showed that at 9 weeks of age, compared with the female hybrid, the male hybrid had higher PCV, NEU and EOS (33.12% ± 2.73%, 31.00% ± 3.37% and 0.38% ± 0.18% respectively) values, while the female NIP had higher WBC, LYM and MON (24.55 ± 1.09 × 103/μl, 56.00% ± 3.24% and 0.50% ± 0.50%) values respectively. At 17 weeks of age, the male hybrid had higher WBC and NEU (32.18 ± 1.92 × 103/μl and 32.38% ± 3.56%) values while the female had higher PCV, LYM, EOS and MON (42.50% ± 1.50%, 63.00% ± 5.0%, 2.50% ± 2.50% and 4.50% ± 1.50%) values. At 25 weeks of age, the female hybrid had higher values in all the parameters with the exception of NEU and MON where male had higher values. These ages can be used as criteria for selection for immunocompetence in pigs.

Partially defatted black soldier fly larva meal inclusion in piglet diets: effects on the growth performance, nutrient digestibility,blood profile, gut morphology and histological features

Background:The aim of this trial was to investigate the effects of different inclusion levels of a partially defatted black soldier fly (BSF,Hermetia illucens L.) larva meal on the growth performance,nutrient digestibility,blood profile,gut morphology and histological features of piglets.A total of 48 newly weaned piglets were individually weighed (initial body weight (IBW):6.1 ± 0.16 kg) and randomly allocated to 3 dietary treatments (4 boxes as replicates/treatment and 4 animals/box).BSF larva meal was included at increasing levels (0% [BSF0],5% [BSFS] and 10% [BSF10]) in isonitrogenous and isoenergetic diets formulated for two feeding phases:Ⅰ (from d 1 to d 23) and Ⅱ (from d 24 to d 61).The weight gain (WG),average daily gain (ADG),average daily feed intake (ADFI) and feed conversion ratio (FCR) were calculated for each feeding phase and for the whole trial.The haematochemical parameters and nutrient digestibility of the piglets were also evaluated.A total of 3 piglets per box were slaughtered on d 61 and the slaughtered piglets were submitted to morphometric investigations and histopathological examinations.Results:No overall significant differences were observed for growth performance (P > 0.05),except for the ADFI of phase Ⅱ,which showed a linear response to increasing BSF meal levels (P < 0.05,maximum for the BSF10 group).Dietary BSF meal inclusion did not significantly influence the blood profile,except as far as monocytes and neutrophils are concerned,and these showed a linear and quadratic response,respectively,to increasing BSF meal levels (P < 0.05,maximum for the BSF10 and BSF5 groups,respectively).On the other hand,the nutrient digestibility,gut morphology and histological features were not affected by dietary BSF meal inclusion (P > 0.05).Conclusions:The obtained results show that a partially defatted BSF larva meal can be used as a feed ingredient in diets for weaned piglets without negatively affecting their growth performance,nutrient digestibility,blood profile,gut morphology or histological features.