Enterotoxigenic Escherichio coli （ETEC） causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of Sou...Enterotoxigenic Escherichio coli （ETEC） causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB （38.9%）, estB/STAP （25%）, and estB/LT （13.9%） were dominant. Risk factors for ETEC-diarrhea in pigs include： leaving sick piglets in a pen with healthy piglets [odds ratio （OR） = 33.52; P 〈 0.0001]; water spillage in pen （OR = 42.87; P 〈 0.0001）; hypothermic piglets （OR = 7.29; P 〈 0.0001）; runt piglets in pen with healthy littermates （OR = 3.65; P 〈 0.0001）; and prolonged use of antibiotics （OR = 3.05; P = 0.05）.展开更多
Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets chal...Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88(ETEC).A total of 961-day-old sow-reared piglets were randomly assigned to 2 groups,with 48 piglets in each group.The piglets were from 16 litters(6 piglets each litter),and 3 piglets each litter were allocated to the E.faecium-supplemented(PRO)group,while the other 3 piglets were allocated to the control(CON)group.After colostrum intake,piglets in the PRO group were orally administrated with 3×10~9 CFU E.faecium per day for a period of one week.On day 8,one piglet per litter from each group was challenged(CON+ETEC,PRO+ETEC)or not(CON-ETEC,PRO-ETEC)with ETEC in a 2×2 factorial arrangement of treatments.On day 10(2 days after challenge),blood and tissue samples were obtained from piglets.Results:Before ETEC challenge,there were no significant differences for the average daily gain(ADG)and fecal score between the two groups of piglets.After ETEC challenge,the challenged piglets had greater fecal score compared to the non-challenged piglets,whereas E.faecium administration was able to decrease the fecal score.Piglets challenged with ETEC had shorter villous height,deeper crypt depth,and reduced number of goblet cells in the jejunum and decreased m RNA abundance of claudin-1 in the ileum,whereas increased the percentage of lymphocytes,concentrations of IL-1βin the plasma and TNF-αin the ileal mucosa,as well as increased the m RNA abundances of innate immunity-related genes in the ileum tissue.These deleterious effects caused by ETEC were partly alleviated by feeding E.faecium.In addition,piglets in PRO-ETEC group had decreased the percentage of CD8^+T cells of the peripheral blood when compared to those in CON-ETEC group.Moreover,E.faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.Conclusions:These results suggest that oral administration of E.faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC,partly through improving the intestinal microbiota and immune response.This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.展开更多
The gene cluster cfaABCED’ of enterotoxigenic Escherichia coli, encoding the fimbriae which is called colonization factor antigen located on a plasmid. It is positively regulated by cfaR, a member of the AraC family,...The gene cluster cfaABCED’ of enterotoxigenic Escherichia coli, encoding the fimbriae which is called colonization factor antigen located on a plasmid. It is positively regulated by cfaR, a member of the AraC family, and the cfaD’ gene region, which is located downstream of cfaE and is homologous to cfaR, had been described as a truncated cryptic gene. In the present study we observed that the CFA/ fimbriae subunit, cfaB, was expressed in lower amount by the cfaABCED’ clone pNTP513 in host E. coli HB101. The expression of CFA/ diminished by deletion of cfaD’ gene region from pNTP513, and was restored by acquisition of cfaD’ in trans. Furthermore, CFA/ expression by cfaD’ deletion mutant, the cfaABCE clone, was remarkably increased by the presence of cfaD’ in trans in a topoisomerase A deficient strain of E. coli DM800. These data suggest that cfaD’ region is a functional region of gene, that regulates the CFA/ expression with cfaR by unknown mechanism.展开更多
Alternatives to antibiotics for preventing bacteria-induced inflammation in early-weaned farm animals are sorely needed. Our previous study showed that Lactiplantibacillus plantarum L47 and inulin could alleviate dext...Alternatives to antibiotics for preventing bacteria-induced inflammation in early-weaned farm animals are sorely needed. Our previous study showed that Lactiplantibacillus plantarum L47 and inulin could alleviate dextran sulfate sodium(DSS)-induced colitis in mice. To explore the protective effects of L. plantarum L47 and inulin on the ileal inflammatory response in weaned piglets challenged with enterotoxigenic Escherichia coli(ETEC), 28 weaned piglets were assigned into four groups, namely, CON group—orally given 10 mL/d phosphate buffer saline(PBS), LI47 group—orally given a mixture of 10 m L/d L. plantarum L47 and inulin, ECON group—orally given 10 mL/d PBS and challenged by ETEC, and ELI47group—orally given 10 mL/d L. plantarum L47 and inulin mixture and challenged by ETEC. The results demonstrated that the combination of L. plantarum L47 and inulin reduced inflammatory responses and relieved the inflammatory damage caused by ETEC, including ileal morphological damage, reduced protein expression of ileal tight junction, decreased antioxidant capacity, and decreased antiinflammatory factors. Transcriptome analysis revealed that L. plantarum L47 and inulin up-regulated the gene expression of phospholipase A2 group IIA(PLA2G2A)(P < 0.05) as well as affected alphalinolenic acid(ALA) metabolism and linoleic acid metabolism. Moreover, L. plantarum L47 and inulin increased the levels of ALA(P < 0.05), lipoteichoic acid(LTA)(P < 0.05), and 12,13-epoxyoctadecenoic acid(12,13-EpOME)(P < 0.05) and the protein expression of Toll-like receptor 2(TLR2)(P = 0.05) in the ileal mucosa. In conclusion, L. plantarum L47 and inulin together alleviated ETEC-induced ileal inflammation in piglets by up-regulating the levels of ALA and 12,13-EpOME via the LTA/TLR2/PLA2G2A pathway.展开更多
This study examines the effects of dietary Macleaya cordata extract(MCE) on bacterial burden and resistance to enterotoxigenic Escherichia coli(ETEC) in ICR mice. ICR mice were randomly distributed into one of the fol...This study examines the effects of dietary Macleaya cordata extract(MCE) on bacterial burden and resistance to enterotoxigenic Escherichia coli(ETEC) in ICR mice. ICR mice were randomly distributed into one of the following groups:(i) basal diet;(ii)basal diet with 200 mg kg–1 MCE;(iii) basal diet challenged with ETEC;and(iv) basal diet with 200 mg kg–1 MCE and challenged with ETEC. Following a 7-day period of pre-treatment, CTRL-ETEC and MCE-ETEC mice were subjected to oral infection using 5×108 E. coli SEC 470. The results showed dietary 200 mg kg–1 MCE markedly reduced intestinal ETEC burden(P<0.05) and the disease-associated mortality was significantly alleviated in the MCE treated group(P<0.05). In addition,dietary MCE markedly alleviated ETEC-induced oxidative stress, evidenced by the lowered methane dicarboxylic aldehyde(MDA) abundance and enhanced activities of catalase and glutathione peroxidase(P<0.05). Furthermore, MCE mice exhibited higher immune activity, which might have further mediated ETEC infection. These results indicate MCE plays a preventative role with respect to ETEC infection. Future research should aim to develop MCE as a therapeutic approach to the promotion of intestinal health and a safeguard against ETEC infection.展开更多
Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to ...Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to pig chromosome(SSC)13q41,and one of the most significantly linked markers is S0075.In this study,we selected three genes including SLC12A8,MYLK and KPNA1 from a chromosomal region flanking S0075 on SSC13 to develop pig specific sequence tagged sites(STS). Seven single nucleotide polymorphisms were identified in the three pig STS using DNA of four full-sib susceptible and resistant animals in a White Duroc×Erhualian intercross.All grandparents,parents and 755 offspring in the intercross were genotyped for three polymorphisms,including SLC12A8 g.159A>G,MYLK g.1673A>G and KPNA1 g.306A>G.Family-based transmission disequilibrium test(TDT) revealed that all polymorphisms and the corresponding haplotypes are significantly associated with ETEC F4ab/ac(especially F4ac)brush border adhesion phenotypes,indicating that these polymor- phism are in linkage disequlibrium with causal mutation(s)of the gene encoding ETEC F4ab/ac receptor. Our results strengthen the evidence for the involvement of SSC13q41 in high acquiring risk of ETEC F4ab/ac infection,and provide novel polymorphic markers for fine mapping of the ETEC F4ab/ac receptor locus.展开更多
This study evaluated the effects of micro-encapsulated(protected)organic acids(OA)and essential oils(EO)combination,P(OA+EO),and effects of a regular blend of free acids(FA)on the growth,immune responses,intestinal ba...This study evaluated the effects of micro-encapsulated(protected)organic acids(OA)and essential oils(EO)combination,P(OA+EO),and effects of a regular blend of free acids(FA)on the growth,immune responses,intestinal barrier and microbiota of weaned piglets challenged with enterotoxigenic Escherichia coli(ETEC)F4(K88^+).A total of 30 crossbred(Duroc×Landrace×Large White)weaned barrows(7.41±0.06 kg,28 d old)were assigned randomly to 5 treatments:1)non-challenged positive control(PC),2)ETEC F4(K88^+)-challenged negative control(NC),3)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+free acidifier(FA)at 5 g/kg,4)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+P(OA+EO)at 1 g/kg(P1),5)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+P(OA+EO)at 2 g/kg(P2).Each dietary treatment had 6 replicates of one piglet each and the study lasted for 3 wk.On d 7,pigs in NC,FA,P1 and P2 were orally dosed with 10 mL of ETEC F4(K88^+)culture(1×10^9 CFU/mL).From d 7 to 14 after the ETEC F4(K88^+)challenge,P1 increased gain-to-feed ratio(G:F)significantly(P<0.05)compared with NC and FA groups.From d 14 to 21,P2 increased the average daily gain of pigs(P<0.05)compared with NC and FA groups.Compared with NC,P2 reduced tumor necrosis factor-α(TNF-α),interleukin(IL)-6 and IL-10 concentrations(P<0.05)in sera collected at 4 h later after ETEC F4(K88^+)challenge.On d 21,P1 increased occludin and zonula occludens-1 protein expression in ileum compared with NC(P<0.05).After this 3-wk experiment,alpha diversity of gut microbiota was decreased by P2 compared with PC,and P1 increased the relative abundance of Lactobacillus in ileum,cecum and colon(P<0.05).In co nclusio n,dietary P(OA+EO)additive at 2 g/kg combined with antibiotics could improve piglet performance and attenuate inflammation,and P(OA+EO)additive at 1 g/kg combined with antibiotics improved intestinal barrier and increased beneficial microbiota composition after an F4(K88^+)challenge.展开更多
Gut health of nursery pigs immediately after weaning is tightly associated with their growth performance and economic values. Postweaning diarrhea(PWD) is one of the major concerns related to gut health of nursery pig...Gut health of nursery pigs immediately after weaning is tightly associated with their growth performance and economic values. Postweaning diarrhea(PWD) is one of the major concerns related to gut health of nursery pigs which often is caused by infections of enterotoxigenic Escherichia coli(ETEC),mainly including F4(K88)^+ and F18^+ E. coli. The main virulence factors of ETEC are adhesins(fimbriae or pili) and enterotoxins. The common types of fimbriae on ETEC from PWD pigs are F18^+ and F4^+. Typically, PWD in pigs is associated with both F18^+ and F4^+ ETEC infections whereas pre-weaning diarrhea in pigs is associated with F4+ ETEC infection. Enterotoxins including heat-labile enterotoxins(LT) and heatstable peptide toxins(ST) are associated with causing diarrhea in pigs. At least 109 to 1010 ETEC are required to induce diarrhea in nursery pigs typically lasting 1 to 5 days after ETEC infection. Antibiotics used to be the most effective way to prevent PWD, however, with the increased bacterial resistance to antibiotics, alternatives to the use of antibiotics are urgently needed to prevent PWD. Immunopropylaxis and nutritional intervention of antimicrobial minerals(such as zinc oxide and copper sulfate), organic acids, functional feedstuffs(such as blood plasma and egg yolk antibodies), direct fed microbials, phytobiotics, and bacteriophage can potentially prevent PWD associated with ETEC. Some other feed additives such as nucleotides, feed enzymes, prebiotic oligosaccharides, and clay minerals can enhance intestinal health and thus indirectly help with preventing PWD. Numerous papers show that nutritional intervention using selected feed additives can effectively prevent PWD.展开更多
文摘Enterotoxigenic Escherichio coli （ETEC） causes neonatal and post-weaning diarrhea in pigs. In order to determine the risk factors, rectal/fecal swabs and visceral organs obtained from pig farms in two regions of South Africa were analyzed microbiologically against risk variables. Seventy-two percent of young pigs were found to be positive for ETEC toxin genes; estB （38.9%）, estB/STAP （25%）, and estB/LT （13.9%） were dominant. Risk factors for ETEC-diarrhea in pigs include： leaving sick piglets in a pen with healthy piglets [odds ratio （OR） = 33.52; P 〈 0.0001]; water spillage in pen （OR = 42.87; P 〈 0.0001）; hypothermic piglets （OR = 7.29; P 〈 0.0001）; runt piglets in pen with healthy littermates （OR = 3.65; P 〈 0.0001）; and prolonged use of antibiotics （OR = 3.05; P = 0.05）.
基金supported by the Projects of The National Key Research and Development Program of China(grant number 2016YFD0501204)Sichuan provincial project on S&T application and demonstration(grant number2016CC0070)the project on commercialization of research findings under funding of government of Sichuan province(grant number16ZHSF0385).
文摘Background:This study aimed to investigate the effects of oral administration of Enterococcus faecium NCIMB10415(E.faecium)on intestinal development,immunological parameters and gut microbiota of neonatal piglets challenged with enterotoxigenic Escherichia coli K88(ETEC).A total of 961-day-old sow-reared piglets were randomly assigned to 2 groups,with 48 piglets in each group.The piglets were from 16 litters(6 piglets each litter),and 3 piglets each litter were allocated to the E.faecium-supplemented(PRO)group,while the other 3 piglets were allocated to the control(CON)group.After colostrum intake,piglets in the PRO group were orally administrated with 3×10~9 CFU E.faecium per day for a period of one week.On day 8,one piglet per litter from each group was challenged(CON+ETEC,PRO+ETEC)or not(CON-ETEC,PRO-ETEC)with ETEC in a 2×2 factorial arrangement of treatments.On day 10(2 days after challenge),blood and tissue samples were obtained from piglets.Results:Before ETEC challenge,there were no significant differences for the average daily gain(ADG)and fecal score between the two groups of piglets.After ETEC challenge,the challenged piglets had greater fecal score compared to the non-challenged piglets,whereas E.faecium administration was able to decrease the fecal score.Piglets challenged with ETEC had shorter villous height,deeper crypt depth,and reduced number of goblet cells in the jejunum and decreased m RNA abundance of claudin-1 in the ileum,whereas increased the percentage of lymphocytes,concentrations of IL-1βin the plasma and TNF-αin the ileal mucosa,as well as increased the m RNA abundances of innate immunity-related genes in the ileum tissue.These deleterious effects caused by ETEC were partly alleviated by feeding E.faecium.In addition,piglets in PRO-ETEC group had decreased the percentage of CD8^+T cells of the peripheral blood when compared to those in CON-ETEC group.Moreover,E.faecium administration increased Verrucomicrobia at phylum level and decreased Bilophila at genus level.Conclusions:These results suggest that oral administration of E.faecium alleviated the intestinal injury and diarrhea severity of neonatal piglets challenged by ETEC,partly through improving the intestinal microbiota and immune response.This offers a potential strategy of dietary intervention against intestinal impairment by ETEC in neonatal piglets.
文摘The gene cluster cfaABCED’ of enterotoxigenic Escherichia coli, encoding the fimbriae which is called colonization factor antigen located on a plasmid. It is positively regulated by cfaR, a member of the AraC family, and the cfaD’ gene region, which is located downstream of cfaE and is homologous to cfaR, had been described as a truncated cryptic gene. In the present study we observed that the CFA/ fimbriae subunit, cfaB, was expressed in lower amount by the cfaABCED’ clone pNTP513 in host E. coli HB101. The expression of CFA/ diminished by deletion of cfaD’ gene region from pNTP513, and was restored by acquisition of cfaD’ in trans. Furthermore, CFA/ expression by cfaD’ deletion mutant, the cfaABCE clone, was remarkably increased by the presence of cfaD’ in trans in a topoisomerase A deficient strain of E. coli DM800. These data suggest that cfaD’ region is a functional region of gene, that regulates the CFA/ expression with cfaR by unknown mechanism.
基金National Key Research and Development Program of China (2021YFD1300301-5)。
文摘Alternatives to antibiotics for preventing bacteria-induced inflammation in early-weaned farm animals are sorely needed. Our previous study showed that Lactiplantibacillus plantarum L47 and inulin could alleviate dextran sulfate sodium(DSS)-induced colitis in mice. To explore the protective effects of L. plantarum L47 and inulin on the ileal inflammatory response in weaned piglets challenged with enterotoxigenic Escherichia coli(ETEC), 28 weaned piglets were assigned into four groups, namely, CON group—orally given 10 mL/d phosphate buffer saline(PBS), LI47 group—orally given a mixture of 10 m L/d L. plantarum L47 and inulin, ECON group—orally given 10 mL/d PBS and challenged by ETEC, and ELI47group—orally given 10 mL/d L. plantarum L47 and inulin mixture and challenged by ETEC. The results demonstrated that the combination of L. plantarum L47 and inulin reduced inflammatory responses and relieved the inflammatory damage caused by ETEC, including ileal morphological damage, reduced protein expression of ileal tight junction, decreased antioxidant capacity, and decreased antiinflammatory factors. Transcriptome analysis revealed that L. plantarum L47 and inulin up-regulated the gene expression of phospholipase A2 group IIA(PLA2G2A)(P < 0.05) as well as affected alphalinolenic acid(ALA) metabolism and linoleic acid metabolism. Moreover, L. plantarum L47 and inulin increased the levels of ALA(P < 0.05), lipoteichoic acid(LTA)(P < 0.05), and 12,13-epoxyoctadecenoic acid(12,13-EpOME)(P < 0.05) and the protein expression of Toll-like receptor 2(TLR2)(P = 0.05) in the ileal mucosa. In conclusion, L. plantarum L47 and inulin together alleviated ETEC-induced ileal inflammation in piglets by up-regulating the levels of ALA and 12,13-EpOME via the LTA/TLR2/PLA2G2A pathway.
基金supported by the National Natural Science Foundation of China (31772642, 31402092)the China Scholarship Council (201708430008), Scientific Research Fund of Hunan Provincial Education Department (17K043)+2 种基金Hunan Provincial Science and Technology Department (2017NK2322, 2018TP2031), China Postdoctoral Science Foundation (2018M632963)Double First-class Construction Project of Hunan Agricultural University (SYL201802002)the Deanship of Scientific Research at King Saud University for its funding of this research through the Research Group Project No. RGP-213
文摘This study examines the effects of dietary Macleaya cordata extract(MCE) on bacterial burden and resistance to enterotoxigenic Escherichia coli(ETEC) in ICR mice. ICR mice were randomly distributed into one of the following groups:(i) basal diet;(ii)basal diet with 200 mg kg–1 MCE;(iii) basal diet challenged with ETEC;and(iv) basal diet with 200 mg kg–1 MCE and challenged with ETEC. Following a 7-day period of pre-treatment, CTRL-ETEC and MCE-ETEC mice were subjected to oral infection using 5×108 E. coli SEC 470. The results showed dietary 200 mg kg–1 MCE markedly reduced intestinal ETEC burden(P<0.05) and the disease-associated mortality was significantly alleviated in the MCE treated group(P<0.05). In addition,dietary MCE markedly alleviated ETEC-induced oxidative stress, evidenced by the lowered methane dicarboxylic aldehyde(MDA) abundance and enhanced activities of catalase and glutathione peroxidase(P<0.05). Furthermore, MCE mice exhibited higher immune activity, which might have further mediated ETEC infection. These results indicate MCE plays a preventative role with respect to ETEC infection. Future research should aim to develop MCE as a therapeutic approach to the promotion of intestinal health and a safeguard against ETEC infection.
基金National High Technology Research and Development Program of China("863"Program)(Grant No.2006AA10Z194)Jiangxi Provincial KeyResearch Project
文摘Neonatal diarrhea caused by enterotoxigenic Escherichia coli(ETEC)F4 is a common and serious disease,resulting in significant economical loss in the pig industry.The locus encoding ETEC F4 receptor has been mapped to pig chromosome(SSC)13q41,and one of the most significantly linked markers is S0075.In this study,we selected three genes including SLC12A8,MYLK and KPNA1 from a chromosomal region flanking S0075 on SSC13 to develop pig specific sequence tagged sites(STS). Seven single nucleotide polymorphisms were identified in the three pig STS using DNA of four full-sib susceptible and resistant animals in a White Duroc×Erhualian intercross.All grandparents,parents and 755 offspring in the intercross were genotyped for three polymorphisms,including SLC12A8 g.159A>G,MYLK g.1673A>G and KPNA1 g.306A>G.Family-based transmission disequilibrium test(TDT) revealed that all polymorphisms and the corresponding haplotypes are significantly associated with ETEC F4ab/ac(especially F4ac)brush border adhesion phenotypes,indicating that these polymor- phism are in linkage disequlibrium with causal mutation(s)of the gene encoding ETEC F4ab/ac receptor. Our results strengthen the evidence for the involvement of SSC13q41 in high acquiring risk of ETEC F4ab/ac infection,and provide novel polymorphic markers for fine mapping of the ETEC F4ab/ac receptor locus.
基金the National Natural Science Foundation of China(31772612)Beijing Municipal Natural Science Foundation(6202019)
文摘This study evaluated the effects of micro-encapsulated(protected)organic acids(OA)and essential oils(EO)combination,P(OA+EO),and effects of a regular blend of free acids(FA)on the growth,immune responses,intestinal barrier and microbiota of weaned piglets challenged with enterotoxigenic Escherichia coli(ETEC)F4(K88^+).A total of 30 crossbred(Duroc×Landrace×Large White)weaned barrows(7.41±0.06 kg,28 d old)were assigned randomly to 5 treatments:1)non-challenged positive control(PC),2)ETEC F4(K88^+)-challenged negative control(NC),3)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+free acidifier(FA)at 5 g/kg,4)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+P(OA+EO)at 1 g/kg(P1),5)NC+kitasamycin at 50 mg/kg+olaquindox at 100 mg/kg+P(OA+EO)at 2 g/kg(P2).Each dietary treatment had 6 replicates of one piglet each and the study lasted for 3 wk.On d 7,pigs in NC,FA,P1 and P2 were orally dosed with 10 mL of ETEC F4(K88^+)culture(1×10^9 CFU/mL).From d 7 to 14 after the ETEC F4(K88^+)challenge,P1 increased gain-to-feed ratio(G:F)significantly(P<0.05)compared with NC and FA groups.From d 14 to 21,P2 increased the average daily gain of pigs(P<0.05)compared with NC and FA groups.Compared with NC,P2 reduced tumor necrosis factor-α(TNF-α),interleukin(IL)-6 and IL-10 concentrations(P<0.05)in sera collected at 4 h later after ETEC F4(K88^+)challenge.On d 21,P1 increased occludin and zonula occludens-1 protein expression in ileum compared with NC(P<0.05).After this 3-wk experiment,alpha diversity of gut microbiota was decreased by P2 compared with PC,and P1 increased the relative abundance of Lactobacillus in ileum,cecum and colon(P<0.05).In co nclusio n,dietary P(OA+EO)additive at 2 g/kg combined with antibiotics could improve piglet performance and attenuate inflammation,and P(OA+EO)additive at 1 g/kg combined with antibiotics improved intestinal barrier and increased beneficial microbiota composition after an F4(K88^+)challenge.
文摘Gut health of nursery pigs immediately after weaning is tightly associated with their growth performance and economic values. Postweaning diarrhea(PWD) is one of the major concerns related to gut health of nursery pigs which often is caused by infections of enterotoxigenic Escherichia coli(ETEC),mainly including F4(K88)^+ and F18^+ E. coli. The main virulence factors of ETEC are adhesins(fimbriae or pili) and enterotoxins. The common types of fimbriae on ETEC from PWD pigs are F18^+ and F4^+. Typically, PWD in pigs is associated with both F18^+ and F4^+ ETEC infections whereas pre-weaning diarrhea in pigs is associated with F4+ ETEC infection. Enterotoxins including heat-labile enterotoxins(LT) and heatstable peptide toxins(ST) are associated with causing diarrhea in pigs. At least 109 to 1010 ETEC are required to induce diarrhea in nursery pigs typically lasting 1 to 5 days after ETEC infection. Antibiotics used to be the most effective way to prevent PWD, however, with the increased bacterial resistance to antibiotics, alternatives to the use of antibiotics are urgently needed to prevent PWD. Immunopropylaxis and nutritional intervention of antimicrobial minerals(such as zinc oxide and copper sulfate), organic acids, functional feedstuffs(such as blood plasma and egg yolk antibodies), direct fed microbials, phytobiotics, and bacteriophage can potentially prevent PWD associated with ETEC. Some other feed additives such as nucleotides, feed enzymes, prebiotic oligosaccharides, and clay minerals can enhance intestinal health and thus indirectly help with preventing PWD. Numerous papers show that nutritional intervention using selected feed additives can effectively prevent PWD.
