Post-weaning Diarrhoea In Pigs Research Articles

Towards identification of new genetic determinants for post-weaning diarrhea in piglets.

Post-weaning diarrhea in pigs is a considerable challenge in the pig farming industry due to its effect on animal welfare and production costs, as well as the large volume of antibiotics, which are used to treat diarrhea in pigs after weaning. Previous studies have revealed loci on SSC6 and SSC13 associated with susceptibility to specific diarrhea causing pathogens. This study aimed to identify new genetic loci for resistance to diarrhea based on phenotypic data. In depth clinical characterization of diarrhea was performed in 257 pigs belonging to two herds during the first 14 days post weaning. The daily diarrhea assessments were used for the classification of pigs into case and control groups. Pigs were assigned to case and control groups based only on the incidence of diarrhea in the second week of the study in order to differentiate between differences in etiology. Genome-wide association studies and metabolomics association analysis were performed in order to identify new biological determinants for diarrhea susceptibility. With the present work, we revealed a new locus for diarrhea resistance on SSC16. Furthermore, studies of metabolomics in the same pigs revealed one metabolite associated with diarrhea.

Botanicals as a zinc oxide alternative to protect intestinal cells from an Escherichia coli F4 infection in vitro by modulation of enterocyte inflammatory response and bacterial virulence.

Pharmacological doses of zinc oxide (ZnO) have been widely used in pig industry to control post-weaning diarrhea (PWD) symptoms exacerbated by enterotoxigenic Escherichia coli F4 infections. Because of environmental issues and regulatory restrictions, ZnO is no longer sustainable, and novel nutritional alternatives to manage PWD are urgently required. Botanicals represent a wide class of compounds employed in animal nutrition because of their diverse beneficial functions. The aim of this study was to investigate the in vitro protective action of a panel of essential oils and natural extracts on intestinal Caco-2 cells against an E. coli F4 infection. Moreover, we explored the potential mechanisms of action of all the botanicals compared to ZnO. Amongst the others, thyme essential oil, grape seed extract, and Capsicum oleoresin were the most effective in maintaining epithelial integrity and reducing bacterial translocation. Their mechanism of action was related to the modulation of cellular inflammatory response, the protection of tight junctions' expression and function, and the control of bacterial virulence, thus resembling the positive functions of ZnO. Moreover, despite their mild effects on the host side, ginger and tea tree essential oils provided promising results in the control of pathogen adhesion when employed during the challenge. These outcomes support the advantages of employing selected botanicals to manage E. coli F4 infections in vitro, therefore offering novel environmentally-friendly alternatives to pharmacological doses of ZnO capable to modulate host-pathogen interaction at different levels during PWD in pigs.

Post-weaning diarrhea in pigs from a single Danish production herd was not associated with the pre-weaning fecal microbiota composition and diversity.

The association between the porcine pre-weaning gut microbiota composition and diversity, and subsequent post-weaning diarrhea (PWD) susceptibility is currently being studied. In this longitudinal study, we examined the association between pre-weaning fecal microbiome composition and diversity, and PWD development in a Danish sow herd. Forty-five pigs were followed from birth until 7 days after weaning (post-natal day (PND) 33). At PND 33, the pigs were categorized as PWD cases or healthy controls based on fecal consistency. We compared their fecal microbiomes at PND 8, late lactation (PND 27) and 7 days post weaning (PND 33) using 16S rRNA V3 region high-throughput sequencing. At PND 27 and 33, we also weighed the pigs, assessed fecal shedding of hemolytic Escherichia coli by culture and characterized hemolytic isolates by ETEC virulence factors with PCR and by whole genome sequencing. A total of 25 out of 45 pigs developed PWD and one Enterotoxigenic E. coli strain with F18:LT:EAST1 virotype was isolated from most pigs. At PND 33, we found differences in beta diversity between PWD and healthy pigs (R2 = 0.027, p = 0.009) and that body weight was associated with both alpha and beta diversity. Pre-weaning fecal microbiome diversity did not differ between PWD and healthy pigs and we found no significant, differentially abundant bacteria between them. In the production herd under study, pre-weaning fecal microbiome diversity and composition were not useful indicators of PWD susceptibility.

Promotion of intestinal epithelial cell apoptosis by enterotoxigenic Escherichia coli via PKA-mediated inhibition of mTORC1 activation

Enterotoxigenic Escherichia coli (ETEC) is the main causative pathogen of diarrhea. It causes acute watery diarrhea that leads to rapid dehydration and prostration within hours. ETEC is still an important cause of neonatal and post-weaning diarrhea in pigs. However, the mechanism underlying ETEC-induced diarrhea is not yet clear. In this study, we investigated these mechanisms and found that the mTORC1 pathway plays a role in the host response to ETEC F4 infection. Specifically, we found that ETEC F4 treatment significantly repressed mTORC1 activity as well as cell proliferation, promoted apoptosis and regulated the expression of diarrhea-related genes via the promotion of PKA-mediated phosphorylation of SIN1, which plays a critical role in the assembly of mTORC2. These findings indicate that PKA is a checkpoint for ETEC-induced diarrhea. In terms of potential therapeutic strategies, we found that ZnSO4 dramatically rescued ETEC F4-induced the inhibition of mTORC1 activity and cell viability and the induction of apoptosis and alterations in the expression of diarrhea-related genes. Thus, the present findings demonstrate that ETEC F4 influences mTORC1 activation by inhibiting the assembly of mTORC2 through PKA-mediated phosphorylation of SIN1. Further, supplementation with ZnSO4 is an effective strategy for blocking the effect of ETEC F4 on mTORC1 activation, and it may have potential clinical applications in the treatment of ETEC F4-induced diarrhea.

Summary of methodology used in enterotoxigenic Escherichia coli (ETEC) challenge experiments in weanling pigs and quantitative assessment of observed variability.

Postweaning diarrhea in pigs is often caused by the F4 or F18 strains of enterotoxigenic Escherichia coli (ETEC). To evaluate interventions for ETEC, experimental infection via a challenge model is critical. Others have reviewed ETEC challenge studies, but there is a lack of explanation for the variability in responses observed. Our objective was to quantitatively summarize the responses and variability among ETEC challenge studies and develop a tool for sample size calculation. The most widely evaluated response criteria across ETEC challenge studies consist of growth performance, fecal consistency, immunoglobulins, pro-inflammatory cytokines, and small intestinal morphology. However, there is variation in the responses seen following ETEC infection as well as the variability within each response criteria. Contributing factors include the type of ETEC studied, dose and timing of inoculation, and the number of replications. Generally, a reduction in average daily gain and average daily feed intake are seen following ETEC challenge as well as a rapid increase in diarrhea. The magnitude of response in growth performance varies, and methodologies used to characterize fecal consistency are not standardized. Likewise, fecal bacterial shedding is a common indicator of ETEC infection, but the responses seen across the literature are not consistent due to differences in bacterial enumeration procedures. Emphasis should also be placed on the piglet's immune response to ETEC, which is commonly assessed by quantifying levels of immunoglobulins and pro-inflammatory cytokines. Again, there is variability in these responses across published work due to differences in the timing of sample collection, dose of ETEC pigs are challenged with, and laboratory practices. Small intestinal morphology is drastically altered following infection with ETEC and appears to be a less variable response criterion to evaluate. For each of these outcome variables, we have provided quantitative estimates of the responses seen across the literature as well as the variability within them. While there is a large degree of variability across ETEC challenge experiments, we have provided a quantitative summary of these studies and a Microsoft Excel-based tool was created to calculate sample sizes for future studies that can aid researchers in designing future work.

Bacillus spp. Probiotic Strains as a Potential Tool for Limiting the Use of Antibiotics, and Improving the Growth and Health of Pigs and Chickens.

The pressure to increasingly optimize the breeding of livestock monogastric animals resulted in antimicrobials often being misused in an attempt to improve growth performance and counteract diseases in these animals, leading to an increase in the problem of antibiotic resistance. To tackle this problem, the use of probiotics, also known as direct in-feed microbials (DFM), seems to be one of the most promising strategies. Among probiotics, the interest in Bacillus strains has been intensively increased in recent decades in pigs and poultry. The aim of the present review was to evaluate the effectiveness of Bacillus strains as probiotics and as a potential strategy for reducing the misuse of antibiotics in monogastric animals. Thus, the potential modes of action, and the effects on the performance and health of pigs (weaning pigs, lactation and gestation sows) and broilers are discussed. These searches yielded 131 articles (published before January 2021). The present review showed that Bacillus strains could favor growth in terms of the average daily gain (ADG) of post-weaning piglets and broilers, and reduce the incidence of post-weaning diarrhea in pigs by 30% and mortality in broilers by 6–8%. The benefits of Bacillus strains on these parameters showed results comparable to the benefit obtained by the use of antibiotics. Furthermore, the use of Bacillus strains gives promising results in enhancing the local adaptative immune response and in reducing the oxidative stress of broilers. Fewer data were available regarding the effect on sows. Discordant effects have been reported regarding the effect on body weight (BW) and feed intake while a number of studies have supported the hypothesis that feeding probiotics to sows could benefit their reproductive performance, namely the BW and ADG of the litters. Taken all the above-mentioned facts together, this review confirmed the effectiveness of Bacillus strains as probiotics in young pigs and broilers, favoring their health and contributing to a reduction in the misuse of direct in-feed antibiotics. The continuous development and research regarding probiotics will support a decrease in the misuse of antibiotics in livestock production in order to endorse a more sustainable rearing system in the near future.

Impact of colistin and colistin-loaded on alginate nanoparticles on pigs infected with a colistin-resistant enterotoxigenic Escherichia coli strain

Colistin is frequently used for the control of post-weaning diarrhoea in pigs. Colistin resistance caused by plasmidic genes is a public health issue. We evaluated, in experimental animal facilities, whether free colistin or colistin-loaded on alginate nanoparticles (colistin/Alg NPs) could select a colistin-resistant Enterotoxigenic Escherichia coli. The Alg NPs were produced by a simple top-down approach through ball milling of sodium alginate polymer precursor, and colistin loading was achieved through physical adsorption. Colistin loading on Alg NPs was confirmed using various tools such Fourier transform infrared spectroscopy and dynamic light scattering measurements. Thirty-four piglets were orally inoculated or not with a mcr-1-positive, rifampicin-resistant enterotoxigenic E. coli strain, and the inoculated pigs were either treated or not during five days with commercial colistin (100,000 IU/kg) or colistin/Alg NPs (40,415 IU/kg). Clinical signs were recorded. Fecal and post-mortem samples were analyzed by culture. The result clearly indicated that colistin/Alg NPs had a slightly better therapeutic effect. Both treatments led to a transitory decrease of the total E. coli fecal population with a majority of colistin-resistant E. coli isolates during treatment, but the dominant E. coli population was found susceptible at the end of the trial. Further studies are needed to evaluate, in diverse experimental or field conditions, the therapeutic efficacy of colistin/Alg NPs for post-weaning diarrhoea.

Post-weaning diarrhea in pigs weaned without medicinal zinc: risk factors, pathogen dynamics, and association to growth rate

BackgroundPorcine post-weaning diarrhea (PWD) has reemerged as an important topic in pig production, as common control strategies based on prophylactic use of antimicrobials and zinc oxide have been deemed unsustainable. The objectives of this study were to estimate the cumulative incidence of porcine post-weaning diarrhea with different etiologies in production systems weaning without zinc oxide and prophylactic antimicrobials, to assess risk factors for post-weaning diarrhea, and to estimate the impact of post-weaning diarrhea on growth rate. A cohort study was conducted at two commercial indoor producers weaning without medicinal zinc oxide and prophylactic antimicrobials.ResultsPiglets were included at birth (n = 300) and 272 survived until weaning. After insertion to the nursery units, the piglets were clinically examined every day for 14 days, and rectal swabs were collected and analyzed for enterotoxigenic Escherichia coli (ETEC) and rotavirus A. The cumulative incidences of PWD the first 14 days after insertion to the nursery units were 41.8% (CI 33.6, 50.4) and 51.1% (CI 42.3, 60.0) at the two producers, respectively. We found a low incidence of cases associated to ETEC, and detected a substantial proportion of cases associated to rotavirus. We observed a biphasic pattern in the assumed etiology with rotavirus occurring first, and then a shift towards cases associated to ETEC/non-ETEC hemolytic E. coli. Being offspring of older sows was a protective factor for the development of PWD (Hazard ratio = 0.88 [CI 0.78, 0.99] per unit increase in parity of the dam). Low birth weight reduced the post-weaning growth rate (− 5.2 g/day [CI − 7.5, − 2.9] per 100 g decrease in birthweight) and increased the hazard of developing PWD (Hazard ratio for birthweight below 1100 g: 2.30 [CI 1.41–3.74]). The combined effect of having diarrhea for 2 days or more and receiving antimicrobial treatment was associated with an increased average daily weight gain.ConclusionsThis study suggests novel insights regarding pathogen dynamics and risk factors for PWD in productions not using prophylactic antimicrobials and medicinal zinc. The findings may have important implications for both antimicrobial usage and prevention strategies.

Evolution of Pig Fecal Microbiota Composition and Diversity in Response to Enterotoxigenic Escherichia coli Infection and Colistin Treatment in Weaned Piglets.

The intestinal microbiota plays several important roles in pig health and growth. The aim of the current study was to characterize the changes in the fecal microbiota diversity and composition of weaned piglets following an oral challenge with an ETEC: F4 strain and/or a treatment with colistin sulfate (CS). Twenty-eight piglets were used in this experiment and were divided into four groups: challenged untreated, challenged treated, unchallenged treated, and unchallenged untreated. Rectal swab samples were collected at five sampling times throughout the study. Total genomic DNA was used to assess the fecal microbiota diversity and composition using the V4 region of the 16S rRNA gene. The relative abundance, the composition, and the community structure of piglet fecal microbiota was highly affected by the ETEC: F4 challenge throughout the experiment, while the oral treatment with CS, a narrow spectrum antibiotic, resulted in a significant decrease of E. coli/Shigella populations during the treatment period only. This study was the first to identify some gut microbiota subgroups (e.g., Streptococcus, Lachnospiraceae) that are associated with healthy piglets as compared to ETEC: F4 challenged animals. These key findings might contribute to the development of alternative strategies to reduce the use of antimicrobials in the control of post-weaning diarrhea in pigs.

Improvement of the Enterotoxigenic Escherichia coli Infection Model for Post-Weaning Diarrhea by Controlling for Bacterial Adhesion, Pig Breed and MUC4 Genotype.

Enterotoxigenic Escherichia coli (ETEC) is a major cause of post-weaning diarrhea (PWD) in pigs and causes significant damage to the swine industry worldwide. In recent years, there has been increased regulation against the use of antibacterial agents in swine due to their health risks. Utilizing experimental models that consistently recapitulate PWD is important for the development of non-antibacterial agents against PWD in pigs. In this study, we established a highly reproducible PWD infection model by examining differences in adhesion of ETEC to the intestinal tissue as well as the association between MUC4 polymorphisms and sensitivity to PWD. Post-weaning diarrhea differences between pig breeds were also examined. The adhesion to enterocytes varied from 104.0 to 106.4 CFU/mL even among the F4 ETEC strains. Experimental infection revealed that PWD can be induced in all MUC4 genotypes after infection with 1010 CFU/pig of highly adherent ETEC, although there were variable sensitivities between the genotypes. Lowly adherent ETEC did not cause PWD as efficiently as did highly adherent ETEC. The incidence of PWD was confirmed for all pigs with the ETEC-susceptible MUC4 genotypes in all of the breeds. These results indicate that high-precision and reproducible experimental infection is possible regardless of pig breeds by controlling factors on the pig-end (MUC4 genotype) and the bacterial-end (adhesion ability).

Influence of zinc on CTX-M-1 β-lactamase expression in Escherichia coli

ObjectiveZinc oxide is used to prevent post-weaning diarrhoea in pigs as an alternative to antimicrobial growth promoters. This study aims to determine if the use of zinc oxide selects for extended-spectrum β-lactamase (ESBL)-producing Escherichia coli and affects the expression of blaCTX-M-1 in E. coli. MethodsUsing an in vitro faecal micro-cosmos model, the selective properties of zinc were investigated using an E. coli strain with blaCTX-M-1 encoded by a natural IncI1 resistance plasmid (MG1655/pTF2) and another strain where the same gene was located on the chromosome (MG1655::blaCTX-M-1). The micro-cosmos was seeded with faecal material containing an increasing concentration of zinc (0–8 mM). Outcome measurements consisted of colony-forming units (CFU) of the inoculated ESBL E. coli and naturally occurring coliforms as determined by plate counting on MacConkey with and without 5 mg/L cefotaxime as well as total viable bacteria determined on Luria agar without cefotaxime. Expression of blaCTX-M-1 under the experimental zinc concentrations was determined by quantitative polymerase chain reaction. ResultsThe proportion of MG1655/pTF2 of the total viable bacteria was significantly higher at high zinc concentrations (6 and 8 mM) compared with low concentrations (0–4 mM). The messenger RNA (mRNA) levels of blaCTX-M-1 in the two ESBL strains increased at increasing zinc concentrations and varied with the growth phase. ConclusionThe growth of the inoculated CTX-M-1-encoding E. coli MG1655 strains and naturally occurring coliforms was impacted differently when exposed to zinc oxide. The blaCTX-M-1 mRNA expression levels seemed to increase with increasing zinc concentrations, but varied with growth phase, but not gene location.

Probiotics as alternatives to antibiotics in treating post-weaning diarrhoea in pigs: Review paper

The use of antibiotics to prevent post-weaning diarrhoea (PWD) in pigs has faced a setback owing to the associated antibiotic resistance in pigs and in the human populace that consumes the pork. In fact, antibiotic resistance that originates from the food chain is estimated to cause around 700,000 deaths globally each year. Consequently, scientists and researchers have suggested possible alternatives to antibiotics in pig diets. The chief of these has been the use of probiotics. The authors reviewed the literature on the use of probiotics as an alternative to antibiotics in treating PWD in pigs. It is clear that because of pathogenic Escherichia coli PWD continues to be a challenge to profitable swine production. The vast number of studies that was reviewed, point to the beneficial effects of probiotic supplementation on reducing the severity and incidence of PWD. However, some studies report inconsistencies to the general hypothesis. The majority of the microorganisms used as probiotics in the studies belong to the genera Lactobacilli , Bacillus , Bifidobacterium , Enterococcus , probiotic Escherichia coli , and Saccharomyces . The review also revealed that the bacterial strains that are used as probiotics are given individually or as combinations of multiple strains, and at various dosages, yielding varied results in each case. Interestingly, the authors observed wide disparities in the onset of probiotic supplementation and duration of the treatment to attain the results. Hence there is a need to standardize supplementation strategies, including dosage, onset and duration of treatment for probiotics. Furthermore, many of the in vivo studies that revealed positive effects of probiotics on diarrhoea and other production parameters were carried out in more controlled environments. The authors therefore suggest that more field studies in more natural and commercial farm settings should be conducted to augment the literature in relation to the use of probiotics as alternatives to antibiotics in treating PWD. Keywords: antimicrobial resistance, directly-fed microorganisms, post-weaning diarrhoea, swine diets

Influence of Zinc Sulphate on the Probiotic Properties of Lactobacillus plantarum CCM 7102

Abstract The effects of zinc sulphate on selected properties of L. plantarum CCM 7102 were tested in vitro. The resistance of lactobacilli to higher concentrations of ZnSO4 (up to 5000 mg Zn2+.l−1) in growth media was strain-dependent. Further studies were carried out on the most resistant strain of L. plantarum CCM 7102. While the addition of low concentrations of zinc sulphate into the growth media (< 100 mg Zn2+.l−1) did not influence the properties of L. plantarum CCM 7102, the concentrations of 100—500 mg Zn2+.l−1 stimulated: the growth rate, production of lactic acid, adhesion to porcine enterocytes and the inhibition of pathogens E. coli O8:K88+ent+, S. enterica and S. Typhimurium. Conversely, however, high concentrations > 500 mg Zn2+.l−1 inhibited these properties. The addition of zinc (250 mg Zn2+.l−1) did not affect the resistance to antimicrobials, low pH, and the resistance to bile salt was affected only weakly. Zinc-resistant probiotic Lactobacillus strains are suitable for use in feedstuffs with a higher content of zinc designed for the prevention of post weaning diarrhoea in pigs.

PSXII-39 Effects of pre-weaning iron supplementation on post-weaning diarrhea in pigs challenged with enterotoxigenic E. coli.

PSXII-39 Effects of pre-weaning iron supplementation on post-weaning diarrhea in pigs challenged with enterotoxigenic E. coli.

High dosage of zinc modulates T-cells in a time-dependent manner within porcine gut-associated lymphatic tissue.

Zn serves as a powerful feed additive to reduce post-weaning diarrhoea in pigs. However, the mechanisms responsible for Zn-associated effects on the adaptive immune responses following feeding of a very high dosage of Zn remain elusive. In this study, we examined the T-cell response in gut-associated lymphatic tissues of seventy-two weaned piglets. Piglets received diets with 57 mg Zn/kg (low Zn concentration, LZn), 164 mg Zn/kg (medium Zn concentration, MZn) or 2425 mg Zn/kg (high Zn concentration, HZn) mg Zn/kg feed for 1, 2 or 4 weeks. We observed that feeding the HZn diet for 1 week increased the level of activated T-helper cells (CD4+ and CD8α dim) compared with feeding MZn and LZn (P<0·05). In addition, we observed higher transcript amounts of interferon γ and T-box 21 (TBET) in the HZn group compared with the MZn and LZn groups (P<0·05). A gene set enrichment analysis revealed an over-representation of genes associated with 'cytokine signalling in immune system'. Remarkably, feeding of a very high Zn dosage led to a switch in the immune response after 2 weeks. We detected higher relative cell counts of CD4+CD25high regulatory T-helper cells (P<0·05) and a higher expression of forkhead box P3 (FOXP3) transcripts (P<0·05). After 4 weeks of feeding a high-dosage Zn diet, the relative CD4+ T-cell count (P<0·05) and the relative CD8β + T-cell count (P<0·1) were reduced compared with the MZn group. We hypothesise that after 1 week the cellular T-helper 1 response is switched on and after 2 weeks it is switched off, leading to decreased numbers of T-cells.

Intestinal challenge with enterotoxigenic Escherichia coli in pigs, and nutritional intervention to prevent postweaning diarrhea.

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 heat-stable 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.

Novel plasmid-mediated colistin resistance mcr-4 gene in Salmonella and Escherichia coli, Italy 2013, Spain and Belgium, 2015 to 2016.

A novel mcr colistin resistance gene was identified in a strain of Salmonella enterica, monophasic variant of serovar Typhimurium (4,5,12:i:- ), isolated from a pig at slaughter in Italy in 2013, and in Escherichia coli strains collected during routine diagnostic of post-weaning diarrhoea in pigs from Spain and Belgium in 2015 and 2016. Immediate implementation of mcr-screening including this novel gene variant is required for Salmonella and E. coli from humans and food-producing animals in Europe.

The fecal presence of enterotoxin and F4 genes as an indicator of efficacy of treatment with colistin sulfate in pigs

BackgroundEnterotoxigenic Escherichia coli (ETEC) strains producing multiple enterotoxins are important causes of post-weaning diarrhea (PWD) in pigs. The aim of the present study was to investigate the fecal presence of ETEC enterotoxin as well as F4 and F18 genes as an indicator of colistin sulfate (CS) efficacy for treatment of PWD in pigs. Forty-eight piglets were weaned at the age of 21 days, and were divided into four groups: challenged treated, challenged untreated, unchallenged treated, and unchallenged untreated. Challenge was performed using 109 CFU of an ETEC: F4 strain, and treatment was conducted using oral CS at the dose of 50,000 IU/kg. The fecal presence of genes encoding for STa, STb, LT, F4 and F18 was detected using PCR.ResultsThe PCR amplification of ETEC virulence genes showed that nearly 100% of pigs excreted genes encoding for STa and STb toxins in the feces before the challenge. These genes, in the absence of the gene encoding F4, were considered as a marker for F4-negative ETEC. One day after ETEC: F4 oral challenge pigs in the two challenged groups excreted the genes encoding LT and F4 in the feces. These genes were considered as a marker for F4-positive ETEC. However, the gene encoding F18 was not detected in any fecal samples of the 4 groups throughout the experiment. After only 3 days of successive oral treatment with CS, a significant reduction in both the F4-positive and negative ETEC populations was observed in the challenged treated group compared to the challenged untreated group (p < 0.0001).ConclusionsOur study is among the first to report that under controlled farming conditions, oral CS treatment had a significant effect on both fecal F4-positive and F4-negative ETEC in pigs. However, CS clinical efficiency was correlated with non-detection of F4-positive ETEC in the feces. Furthermore the fecal presence of F4-negative ETEC was not associated with clinical symptoms of post-weaning diarrhea in pigs.

A comparative study of the efficacy of Detach® versus zinc oxide to control post-weaning diarrhoea in pigs

Animal Production Science (continuing Australian Journal of Experimental Agriculture) publishes original research into applied agriculture including animal production, animal-plant interactions, pasture and fodder crops, field crops, extension and horticulture

Electrochemical sensor for the determination of enterotoxigenic Escherichia coli in swine feces using glassy carbon electrodes modified with multi-walled carbon nanotubes

Enterotoxigenic Escherichia coli F4 (K88) (ETEC F4) is one of the main etiologic agents involved in neonatal and post-weaning diarrhea in pigs, which generates significant economic losses due to high mortality and morbidity.An electrochemical sensor based on glassy carbon electrodes modified with a dispersion of multi-walled carbon nanotubes plus 1% Nafion™ is proposed to detect and quantify ETEC F4 in stool samples of pigs. The preparation of samples was made by dilution in phosphate buffer solutions (PBSs), followed by centrifugation and inactivation of the supernatant in autoclave. An irreversible oxidation peak was observed by cyclic voltammetry at a potential close to 0.69V. The best response was obtained for an optimum pre-concentration time of 10min under forced convection conditions. The electrochemical response performed by square wave voltammetry was obtained in 1/5000 fecal samples in PBS spiked with ETEC F4. A peak current vs. ETEC F4 concentration plot was constructed from successive additions of suspensions of ETEC F4 inactivated by autoclave. The limit of detection (LOD), the limit of quantitation (LOQ) and the relative standard deviation were 6×104CFUmL−1, 2×105CFUmL−1 and 20%, respectively. The developed electrochemical method is simple, fast and economical to quantify ETEC F4 in swine stool samples, making it useful for diagnosis monitoring in production facilities.