Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive...Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E_2(PGE_2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.Methods: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs(Landrace × Large White) weighing 6.6 ± 0.04 kg(mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation(50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate).Results: Acetylsalicylic acid supplementation improved average daily gain(P < 0.05) and tended to improve feed:gain ratio(P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved(P < 0.001) amino acid utilization efficiency(as assessed by plasma urea level) and tended to decrease(P < 0.10) PGE_2 production in the liver without affecting smal intestinal histology and tight junction protein mR NA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration(P < 0.001) and plasma haptoglobin content(P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs.Conclusions: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE_2 and inflammatory responses in weaner pigs experimental y infected with an enterotoxigenic strain of E. coli.展开更多
Background: This study investigated the validity of the DNA-marker based test to determine susceptibility to ETECF4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experime...Background: This study investigated the validity of the DNA-marker based test to determine susceptibility to ETECF4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experimental infection with F4 enterotoxigenic Escherichia coli(ETEC-F4). The effects of diet and genetic susceptibility were assessed by measuring the incidence of piglet post-weaning diarrhoea(PWD), faecal E. coli shedding and the diarrhoea index.Results: A DNA marker-based test targeting the mucin 4 gene(MUC4) that encodes F4 fimbria receptor identified pigs as either fully susceptible(SS), partially or mildly susceptible(SR), and resistant(RR) to developing ETEC-F4 diarrhoea. To further analyse this, DNA sequencing was undertaken, and a significantly higher proportion of C nucleotides was observed for RR and SR at the Xba I cleavage site genotypes when compared to SS. However, no significant difference was found between SR and RR genotypes. Therefore, results obtained from Sanger sequencing retrospectively allocated pigs into a resistant genotype(MUC4–), in the case of a C nucleotide, and a susceptible genotype(MUC4+), in the case of a G nucleotide, at the single nucleotide polymorphism site. A total of 72 weaner pigs(age ~ 21 days), weighing 6.1 ± 1.2 kg(mean ± SEM), were fed 3 different diets:(i) positive control(PC) group supplemented with 3 g/kg zinc oxide(Zn O),(ii) negative control(NC) group(no Zn O or HAMSA),and(iii) a diet containing a 50 g/kg high-amylose maize starch product(HAMSA) esterified with acetate. At days five and six after weaning, all pigs were orally infected with ETEC(serotype O149:F4;toxins LT1, ST1, ST2 and EAST). The percentage of pigs that developed diarrhoea following infection was higher(P = 0.05) in MUC4+ pigs compared to MUC4– pigs(50% vs. 26.8%, respectively). Furthermore, pigs fed Zn O had less ETEC-F4 diarrhoea(P = 0.009) than pigs fed other diets, however faecal shedding of ETEC was similar(P > 0.05) between diets.Conclusion: These results confirm that MUC4+ pigs have a higher prevalence of ETEC-F4 diarrhoea following exposure, and that pigs fed Zn O, irrespective of MUC4 status, have reduced ETEC-F4 diarrhoea. Additionally,sequencing or quantifying the single nucleotide polymorphism distribution at the Xba I cleavage site may be more reliable in identifying genotypic susceptibility when compared to traditional methods.展开更多
基金support by Australian Cooperative Research Centre for High Integrity Australian Pork(Award number 2C-110 1213)
文摘Background: This experiment was conducted to test the hypothesis that vitamin E(Vit E) and acetylsalicylic acid(ASA), a cyclooxygenase-2(COX-2) inhibitor, will additively reduce the production of the immunosuppressive molecule prostaglandin E_2(PGE_2) and hence reduce inflammatory responses in weaner pigs experimentally infected with an enterotoxigenic strain of E. coli.Methods: The experiment was conducted in a research facility with 192 individually-housed male weaner pigs(Landrace × Large White) weighing 6.6 ± 0.04 kg(mean ± SEM). The pigs were experimentally infected with an enterotoxigenic strain of E. coli and were allocated to a 2 × 3 factorial design with the respective factors being without and with 125 ppm ASA and three levels of Vit E supplementation(50, 100 or 200 IU/kg diet, dl-α-tocopheryl acetate).Results: Acetylsalicylic acid supplementation improved average daily gain(P < 0.05) and tended to improve feed:gain ratio(P < 0.10) during the first 14 d after weaning. Acetylsalicylic acid supplementation also improved(P < 0.001) amino acid utilization efficiency(as assessed by plasma urea level) and tended to decrease(P < 0.10) PGE_2 production in the liver without affecting smal intestinal histology and tight junction protein mR NA expression in the jejunal epithelium. Vitamin E supplementation greater than 100 IU/kg diet sustained both the plasma Vit E concentration(P < 0.001) and plasma haptoglobin content(P < 0.001) after weaning. However, there was no additive effects of the combined supplementation of ASA and Vit E on performance, intestinal barrier function and inflammatory responses of weaned pigs.Conclusions: Although ASA and vitamin E improved amino acid utilization efficiency and reduced acute inflammatory responses, ASA and vitamin E did not additively reduce production of PGE_2 and inflammatory responses in weaner pigs experimental y infected with an enterotoxigenic strain of E. coli.
基金Australian Pork Limited and the Cooperative Research Centre for High Integrity Australian Pork(Pork CRC)for funding this studyan Australian Pork Limited Postgraduate Scholarship
文摘Background: This study investigated the validity of the DNA-marker based test to determine susceptibility to ETECF4 diarrhoea by comparing the results of two DNA sequencing techniques in weaner pigs following experimental infection with F4 enterotoxigenic Escherichia coli(ETEC-F4). The effects of diet and genetic susceptibility were assessed by measuring the incidence of piglet post-weaning diarrhoea(PWD), faecal E. coli shedding and the diarrhoea index.Results: A DNA marker-based test targeting the mucin 4 gene(MUC4) that encodes F4 fimbria receptor identified pigs as either fully susceptible(SS), partially or mildly susceptible(SR), and resistant(RR) to developing ETEC-F4 diarrhoea. To further analyse this, DNA sequencing was undertaken, and a significantly higher proportion of C nucleotides was observed for RR and SR at the Xba I cleavage site genotypes when compared to SS. However, no significant difference was found between SR and RR genotypes. Therefore, results obtained from Sanger sequencing retrospectively allocated pigs into a resistant genotype(MUC4–), in the case of a C nucleotide, and a susceptible genotype(MUC4+), in the case of a G nucleotide, at the single nucleotide polymorphism site. A total of 72 weaner pigs(age ~ 21 days), weighing 6.1 ± 1.2 kg(mean ± SEM), were fed 3 different diets:(i) positive control(PC) group supplemented with 3 g/kg zinc oxide(Zn O),(ii) negative control(NC) group(no Zn O or HAMSA),and(iii) a diet containing a 50 g/kg high-amylose maize starch product(HAMSA) esterified with acetate. At days five and six after weaning, all pigs were orally infected with ETEC(serotype O149:F4;toxins LT1, ST1, ST2 and EAST). The percentage of pigs that developed diarrhoea following infection was higher(P = 0.05) in MUC4+ pigs compared to MUC4– pigs(50% vs. 26.8%, respectively). Furthermore, pigs fed Zn O had less ETEC-F4 diarrhoea(P = 0.009) than pigs fed other diets, however faecal shedding of ETEC was similar(P > 0.05) between diets.Conclusion: These results confirm that MUC4+ pigs have a higher prevalence of ETEC-F4 diarrhoea following exposure, and that pigs fed Zn O, irrespective of MUC4 status, have reduced ETEC-F4 diarrhoea. Additionally,sequencing or quantifying the single nucleotide polymorphism distribution at the Xba I cleavage site may be more reliable in identifying genotypic susceptibility when compared to traditional methods.