Coli Challenge Research Articles

Impact of particle size of cereals and soyabean meal on the intestinal development of weanling pigs and growth performance after an enteric challenge with F4-positive enterotoxigenic E. coli.

The objectives were to determine the interactive effect of particle size of soyabean meal (SBM) and whole wheat, barley and wheat bran (CER) on growth performance of weanling pigs after an enterotoxigenic Escherichia coli F4 challenge (Experiment 1) and on gastrointestinal (GIT) development immediately after weaning (Experiment 2). Experiment 1 consisted of 192 pigs (24 ± 3 days of age; 7.4 ± 1.1 kg weaning bodyweight [BW]) selected for Escherichia coli (E. coli) F4 susceptibility. Pigs were given an oral E. coli inoculum at postweaning day 7, to induce an enteric health challenge. Experiment 2 consisted of 40 pigs (24 ± 3 days of age; 7.2 ± 1.0 kg weaning BW) that were killed on postweaning day 8 or 9, to determine the effects of particle size on GIT development and functionality. Four experimental diets were used in a 2 × 2 factorial design: (1) coarse CER and coarse SBM, (2) coarse CER and fine SBM (CERcSBMf), (3) fine CER and coarse SBM, or (4) fine CER and fine SBM (CERfSBMf). Results showed no interaction between SBM and CER coarseness on growth performance, GIT development and functionality. Diarrhoea incidence was higher (p < 0.05) for CERfSBMf during the 2 weeks following the E. coli challenge compared to the other diets. Daily gain and feed intake during this period were higher (p < 0.05) for pigs fed CERc compared to CERf. Empty stomach weight tended to be greater by 8% (p = 0.09) for CERc compared to CERf. Gastric protein (p = 0.05) and starch (p = 0.04) disappearances were greater for SBMf compared to SBMc. Thus, CERcSBMf resulted in the best growth performance and lowest diarrhoea incidence during the 2 weeks following the E. coli challenge, which may be explained by changes in stomach functionality but not by changes in other parts of the GIT.

Cows with diverging haplotypes show differences in differential milk cell count, milk parameters and vaginal temperature after S. aureus challenge but not after E. coli challenge

BackgroundIn dairy cattle, mastitis causes high financial losses and impairs animal well-being. Genetic selection is used to breed cows with reduced mastitis susceptibility. Techniques such as milk cell flow cytometry may improve early mastitis diagnosis. In a highly standardized in vivo infection model, 36 half-sib cows were selected for divergent paternal Bos taurus chromosome 18 haplotypes (Q vs. q) and challenged with Escherichia coli for 24 h or Staphylococcus aureus for 96 h, after which the samples were analyzed at 12 h intervals. Vaginal temperature (VT) was recorded every three minutes. The objective of this study was to compare the differential milk cell count (DMCC), milk parameters (fat %, protein %, lactose %, pH) and VT between favorable (Q) and unfavorable (q) haplotype cows using Bayesian models to evaluate their potential as improved early indicators of differential susceptibility to mastitis.ResultsAfter S. aureus challenge, compared to the Q half-sibship cows, the milk of the q cows exhibited higher PMN levels according to the DMCC (24 h, p < 0.001), a higher SCC (24 h, p < 0.01 and 36 h, p < 0.05), large cells (24 h, p < 0.05) and more dead (36 h, p < 0.001) and live cells (24 h, p < 0.01). The protein % was greater in Q milk than in q milk at 0 h (p = 0.025). In the S. aureus group, Q cows had a greater protein % (60 h, p = 0.048) and fat % (84 h, p = 0.022) than q cows. Initially, the greater VT of S. aureus-challenged q cows (0 and 12–24 h, p < 0.05) reversed to a lower VT in q cows than in Q cows (48–60 h, p < 0.05).Additionally, the following findings emphasized the validity of the model: in the S. aureus group all DMCC subpopulations (24 h-96 h, p < 0.001) and in the E. coli group nearly all DMCC subpopulations (12 h-24 h, p < 0.001) were higher in challenged quarters than in unchallenged quarters. The lactose % was lower in the milk samples of E. coli-challenged quarters than in those of S. aureus-challenged quarters (24 h, p < 0.001). Between 12 and 18 h, the VT was greater in cows challenged with E. coli than in those challenged with S. aureus (3-h interval approach, p < 0.001).ConclusionThis in vivo infection model confirmed specific differences between Q and q cows with respect to the DMCC, milk component analysis results and VT results after S. aureus inoculation but not after E. coli challenge. However, compared with conventional milk cell analysis monitoring, e.g., the global SCC, the DMCC analysis did not provide refined phenotyping of the pathogen response.

Redox balance and immunity of piglets pre- and post-E. coli challenge after treatment with hemp or fish oil, and vitamin E

This study investigated the influence of polyunsaturated fatty acid composition and vitamin E supplementation on oxidative status and immune responses in weanling piglets pre- and post-E. coli challenge. Suckling piglets (n = 24) were randomly selected from two litters for an oral supplementation (1 mL/day) with fish oil or hemp oil and vitamin E supplementation (60 mg natural vitamin E/mL oil) from day 10 to 28 of age. At day 29 and 30 of age, each piglet was orally inoculated with 6.7 × 108 and 3.96 × 108 CFU of F4 and F18 E. coli, respectively. Blood was sampled from all piglets on day 28 before E. coli challenge and on day 35 of age to investigate immunological and oxidative stress markers in plasma. One week after weaning and exposure to E. coli, a general reduction in the α-tocopherol concentration and activity of GPX1 was obtained. Vitamin E supplementation lowered the extent of lipid peroxidation and improved the antioxidative status and immune responses after E. coli challenge. Hemp oil had the greatest effect on antioxidant enzyme activity. Provision of hemp oil and vitamin E to suckling piglets may reduce the incidence of post-weaning diarrhea.

181 Effects of Soy protein concentrate replacing conventional soybean meal on intestinal health and growth of newly weaned pigs challenged with F18+ Escherichia coli.

Abstract This study aims to investigate the impact of various levels of soy protein concentrate (SPC) replacing conventional soybean meal (SBM) on various parameters related to intestinal health and growth performance of nursery pigs under F18+ Escherichia coli challenge. Newly weaned pigs [n = 72; initial body weight (BW) = 6.6 ± 0.3 kg] were randomly allotted to 6 treatment groups based on randomized complete block design with initial BW and sex as blocks and fed for 25 d (P1/2 for 11/14 d, respectively). The treatment groups were 1) NC: a diet with conventional SBM, 2) PC: NC with F18+ E. coli challenge at d 7 (2.1 × 1010 CFU); 3) T1: PC with 5% SPC replacing conventional SBM; 4) T2: PC with 10% SPC replacing conventional SBM; 55) T3: NC with 10% SPC replacing conventional SBM, and 6) AGP: PC with 0.25% bacitracin methylene disalicylate. At the end of study, all pigs were euthanized to collect jejunal tissues to measure parameters related to intestinal health. Data were analyzed using MIXED procedure in SAS. The PC decreased (P &amp;lt; 0.05) average daily gain (ADG) and average daily feed intake (ADFI) on d 7 to d 25 (post-challenge) compared with NC. The T2 decreased (P &amp;lt; 0.05) ADG and ADFI on post-challenge period compared with T3. The ADG tended to linearly decrease (P = 0.067) and ADFI linearly decrease (P &amp;lt; 0.05) on post-challenge period with increasing SPC supplementation replacing SBM in the diets. The E. coli challenge increased (P &amp;lt; 0.05) fecal score in PC, and T2 treatments compared with NC, and T3, respectively. The tumor necrosis factor-alpha (TNF-α) in jejunal mucosa linearly increased (P &amp;lt; 0.05) with increasing SPC supplementation replacing SBM in nursery diets under E. coli challenge. The PC decreased (P &amp;lt; 0.05) interleukin-8 (IL-8) compared with NC. The PC (P = 0.078) and T3 (P = 0.099) tended to decrease immunoglobulin A (IgA) compared with NC. The AGP increased (P &amp;lt; 0.05) IgA compared with PC. The AGP increased (P &amp;lt; 0.05) the expression of occludin (OC) compared with PC. The expression of OC tended to linearly decrease (P = 0.099) with increasing SPC supplementation replacing SBM in nursery diets under E. coli challenge. The T2 increased (P &amp;lt; 0.05) villus height to crypt depth ratio (VH:CD) compared with T3. In conclusion, supplementation of SPC replacing SBM in the diet did not alleviate the deleterious effect of E. coli challenge on growth performance nursery pigs, which might be contributed by reduced feed intake. Additionally, supplementation of SPC seems to exacerbate the negative effect of E. coli challenge with increased intestinal inflammation and intestinal disintegration.

Gastrointestinal response to the early administration of antimicrobial agents in growing turkeys infected with Escherichia coli

This study investigated the effects of the early administration of enrofloxacin (E) or doxycycline (D) for the first 5 consecutive days of life, or the continuous administration of the coccidiostat monensin (M) throughout the rearing period on gastrointestinal function in turkeys infected with avian pathogenic Escherichia coli (APEC) in an early or later stage of rearing. Experiment 1 lasted 21 d, and turkeys in groups E, D, and M were infected with APEC on d 15. Experiment 2 lasted 56 d, and it had a factorial arrangement of treatments where birds in groups E, D, and M were infected with APEC on d 15 or d 50. In both experiments, control groups (C) consisted of infected and uninfected birds without antibiotic or coccidiostat administration. On d 21 (Experiment 1) and d 56 (Experiment 2), 8 birds from each subgroup were killed, and the ileal and cecal digesta were sampled to analyze the activity of bacterial enzymes and the concentrations of short-chain fatty acids (SCFA). The experimental treatments did not affect the final body weight or body weight gain of birds. Both experiments demonstrated that APEC contributed to an increase in ammonia levels of the cecal digesta (means from 2 experiments: 0.311 vs. 0.225 mg/g in uninfected birds) and ileal pH (6.79 vs. 6.00) and viscosity (2.43 vs. 1.83 mPa⋅s). Moreover, the E. coli challenge enhanced the extracellular activity of several cecal bacterial enzymes, especially in older turkeys infected with APEC in a later stage of life. The continuous administration of monensin throughout the rearing period resulted in a weaker gastrointestinal response in older birds, compared with the other 2 antibiotics administered for the first 5 d of life. The results of the study are inconclusive as both desirable and undesirable effects of preventive early short-term antibiotic therapy were observed in turkeys, including normalization of ileal viscosity and cecal ammonia concentration (positive effect), and disruption in cecal SCFA production (negative effect).

Transcriptomic analysis of intestinal organoids, derived from pigs divergent in feed efficiency, and their response to Escherichia coli

BackgroundThere is increasing interest in using intestinal organoids to study complex traits like feed efficiency (FE) and host-microbe interactions. The aim of this study was to investigate differences in the molecular phenotype of organoids derived from pigs divergent for FE as well as their responses to challenge with adherent and invasive Escherichia coli (E. coli).ResultsColon and ileum tissue from low and high FE pigs was used to generate 3D organoids and two dimensional (2D) monolayers of organoid cells for E. coli challenge. Genome-wide gene expression was used to investigate molecular differences between pigs that were phenotypically divergent for FE and to study the difference in gene expression after challenge with E. coli. We showed, (1) minor differences in gene expression of colon organoids from pigs with low and high FE phenotypes, (2) that an E. coli challenge results in a strong innate immune gene response in both colon and ileum organoids, (3) that the immune response seems to be less pronounced in the colon organoids of high FE pigs and (4) a slightly stronger immune response was observed in ileum than in colon organoids.ConclusionsThese findings demonstrate the potential for using organoids to gain insights into complex biological mechanisms such as FE.

PSIV-27 Effect of Different Ratios of Phytogenic Feed Additives in Weaned Pigs Challenged with a Pathogenic Escherichia Coli

Abstract This study was conducted to investigate the effects of supplementing different ratios of phytogenic feed additive (PFA) to weaned pigs challenged with pathogenic Escherichia coli (E. coli) on growth performance, nutrient digestibility, intestinal barrier integrity, and immune response, and to determine the optimal mixing ratio for PWD prevention. A total of 48 four-week-old weaned pigs with initial body weight of 8.01 ± 0.39 kg were placed in individual metabolic cages, and then randomly assigned to eight treatment groups. The eight treatments were as follows: a basal diet without E. coli challenge (negative control, NC), a basal diet with E. coli challenge (positive control, PC), PC with supplementing 0.1% mixture of 20 % bitter citrus extract (BCE), 10% microencapsulated blend of thymol and carvacrol (MEO), and 70% excipient (T1), PC with supplementing 0.1% mixture of 10% MEO, 20% premixture of grape seed and grape marc extract, green tea, and hops (PGE), and 60% excipient (T2), PC with supplementing 0.1% mixture of 10% BCE, 10% MEO, 10% PGE, and 70% excipient (T3), PC with supplementing 0.1% mixture of 20% BCE, 20% MEO, and 60% excipient (T4), PC with supplementing 0.1 % mixture of 20% MEO, 20% PGE, and 60% excipient (T5), and PC with supplementing 0.1 % mixture of 10% BCE, 20% MEO, 10% PGE, and 60% excipient (T6; Table 1). The experiments were progressed in 16 days, including 5 days before and 11 days after the first E. coli challenge (d 0). In the E. coli challenge treatments, all pigs were orally inoculated by dividing a total of 10 mL of E. coli F 18 for 3 consecutive days from d 0 post-inoculation (PI). Compared with the PC group, the PFA2 and PFA6 groups significantly increased (P &amp;lt; 0.05) feed efficiency and decreased (P &amp;lt; 0.05; Table 2) diarrhea during the entire period (Table 3). At d 11 PI, the PFA6 group significantly improved (P &amp;lt; 0.05) gross energy digestibility compared with the PFA1 group (Table 4). The PFA6 group significantly decreased (P &amp;lt; 0.05) tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) in serum (Table 5) and increased (P &amp;lt; 0.05) the villus height to crypt depth ratio (VH:CD; Table 6; Figure 1). The PFA2 significantly decreased (P &amp;lt; 0.05) the relative protein expression of calprotectin in the ileum (Table 7). In conclusion, improvements in growth performance, diarrhea reduction, and immunity enhancement are demonstrated when 10% BCE, 20% MEO, 10% PGE, and 60% excipient are mixed.

145 Dose-Response and Functional Roles of Zinc Glycinate on Growth and Intestinal Health of Nursery Pigs Challenged with F18+Escherichia Coli

Abstract This study was to evaluate dose-response and supplemental effects of zinc glycinate (ZnGly) on growth and intestinal health of nursery pigs challenged with F18+Escherichia coli. Nursery pigs (n = 40; BW = 6.5 ± 0.5 kg) were allotted to 5 treatments in a randomized complete block design with BW and sex as blocks: 1) NC: no-challenge/no-supplement; (2) PC: F18+E. coli challenge/no-supplement; (3 to 5) F18+E. coli challenge/supplementations of ZnGly at 400, 800, and 1,200 mg/kg. On d 7, challenged groups were orally inoculated with F18+E. coli at 6 × 109 CFU/mL, whereas NC received saline solution. Pigs were fed for 28 d based on 2 phases (Phase 1: 14 d and phase 2: 14 d), and experimental diets were formulated to meet or exceed nutrient requirements suggested by NRC (2012). Pigs were euthanized on d 28 to collect tissues to evaluate TNF-α, IL-8, malondialdehyde, protein carbonyl, gene expression of Zn transporters, and mucosa-associated microbiota in the jejunum. Data were analyzed using contrasts in the MIXED procedure of SAS. The E. coli challenge tended to reduce (P = 0.065) ADG (308 to 244 g/d) and increase (P &amp;lt; 0.05) fecal score (3.2 to 4.1) of the pigs during the first week of post-challenge. Supplementation of ZnGly from 0 to 1,200 mg/kg linearly (P = 0.092) increased G:F (0.69 to 0.81) during phase 1 and decreased (P &amp;lt;0.05) fecal score (4.1 to 3.5) of the pigs during the first week of post-challenge. Supplementation of ZnGly from 0 to 1,200 mg/kg had quadratic effects on TNF-α (P = 0.065; minimum 1.51 pg/mg at 405 mg/kg of ZnGly), IL-8 (P = 0.093; minimum 0.53 ng/mg at 494 mg/kg), and protein carbonyl (P = 0.054; minimum 2.30 pg/mg at 675 mg/kg) and linearly increased mRNA expressions of (P = 0.057) ZIP4 (0.69 to 1.03) and (P = 0.075) ZnT5 (0.92 to 1.22) in the jejunum of the pigs. Supplementation of ZnGly from 0 to 1,200 mg/kg tended to linearly decrease (P = 0.065) Chao1 index (150.6 to 144.6) and linearly increased (P &amp;lt; 0.05) relative abundance of Actinobacteria (13.10 to 16.26%) and had quadratic effects (P &amp;lt; 0.05) on the relative abundance of Cyanobacteria (minimum 0.67 % at 625 mg/kg) and Proteobacteria (minimum 45.6% at 735 mg/kg) at the phylum level with Enterobacteriaceae (minimum 4.79% at 660 mg/kg) at family level in jejunal mucosa-associated microbiota of the pigs. In conclusion, supplementation of ZnGly at a range of 400 to 675 mg/kg could reduce the negative impacts of F18+E. coli on growth performance and diarrhea of nursery pigs. These positive changes are related to reducing jejunal inflammation and oxidative stress by enhancing jejunal Zn absorption with positive changes in jejunal mucosa-associated microbiota in the pigs.

146 Efficacy of Zinc Glycinate Reducing Zinc Oxide on Growth and Intestinal Health of Nursery Pigs Challenged with F18+Escherichia Coli

Abstract The objective of this study was to investigate the effect of ZnGly supplementation reducing ZnO in feeds on growth performance and intestinal health of nursery pigs challenged with F18+Escherichia coli (E. coli). A total of 56 nursery pigs (initial BW = 6.5 ± 0.5 kg) were allotted to 7 treatments based on a randomized complete block design using BW and sex as blocks. Treatment groups were: 1) NC: no-challenged with E. coli; 2) PC: challenged with F18+E. coli; 3) challenged with F18+ E. coli and fed ZnO at 2,500 mg/kg in the diet; (4 to 7) challenged with F18+E. coli and fed ZnGly at 400 mg/kg and ZnO at 0, 700, 1,400, and 2,357 mg/kg in the diets. Pigs were fed for 28 days based on 2 phases (Phase 1: 14 d and phase 2: 14 d) and 48 pigs were orally inoculated with F18+ E. coli (6 × 109 CFU/mL) on d 7. Pigs were euthanized on d 28 to collect tissues to evaluate TNF-α, IL-8, malondialdehyde, protein carbonyl, gene expression of Zn transporters, and mucosa-associated microbiota in the jejunum. Data were analyzed by Mixed procedure of SAS. The E. coli challenge tended to decrease (P = 0.076) ADG (200 to 155 g/d) and (P = 0.055) G:F (0.82 to 0.69) during phase 1, and increased (P &amp;lt; 0.05) fecal score (3.2 to 4.1) of nursery pigs during d 7 to 14. There was no difference on the growth performance during the overall period, although pigs fed with the pharmaceutical level of ZnO had greater (P &amp;lt; 0.05) ADG (343 vs. 256 g/d) than pigs fed with ZnGly at 400 mg/kg during the first week of post-challenge. Supplementation of ZnGly with reducing the levels of ZnO from 2,357 to 0 mg/kg tended to have a quadratic response on the fecal score (maximum 4.2 at 667 mg/kg of ZnO) during post-challenge period. Supplementation of ZnGly with reducing levels of ZnO from 2,357 to 0 mg/kg linearly decreased (P &amp;lt; 0.05) IL-8 (0.94 to 0.58 ng/mg) and malondialdehyde (0.49 to 0.34 μM/mg) in jejunum of the pigs. Supplementation of ZnGly reducing the levels of ZnO from 2,357 to 0 mg/kg linearly increased (P &amp;lt; 0.05) Chao1 (142.2 to 148.7) and decreased (P &amp;lt; 0.05) Shannon (4.08 to 3.99) with quadratic effects (P &amp;lt; 0.05) on relative abundance of Pseudomonadaceae (minimum 6.15% at 1,000 mg/kg) and Streptomycetaceae (minimum 5.91% at 800 mg/kg) at family level in jejunum of the pigs. In conclusion, ZnGly supplementation at 400 mg/kg could effectively reduce the use of ZnO in nursery feeds by having similar effects to the pharmaceutical use of ZnO without negatively affecting growth performance and intestinal health of pigs challenged with F18+E. coli.

52 (P4-4). Oxidative stress status in weanling piglets pre- and post-E. coli challenge after treatment with hemp, fish oil and vitamin E

52 (P4-4). Oxidative stress status in weanling piglets pre- and post-E. coli challenge after treatment with hemp, fish oil and vitamin E

Functional Analysis of a CTL-X-Type Lectin CTL16 in Development and Innate Immunity of Tribolium castaneum.

C-type lectins (CTLs) are a class of proteins containing carbohydrate recognition domains (CRDs), which are characteristic modules that recognize various glycoconjugates and function primarily in immunity. CTLs have been reported to affect growth and development and positively regulate innate immunity in Tribolium castaneum. However, the regulatory mechanisms of TcCTL16 proteins are still unclear. Here, spatiotemporal analyses displayed that TcCTL16 was highly expressed in late pupae and early adults. TcCTL16 RNA interference in early larvae shortened their body length and narrowed their body width, leading to the death of 98% of the larvae in the pupal stage. Further analysis found that the expression level of muscle-regulation-related genes, including cut, vestigial, erect wing, apterous, and spalt major, and muscle-composition-related genes, including Myosin heavy chain and Myosin light chain, were obviously down-regulated after TcCTL16 silencing in T. castaneum. In addition, the transcription of TcCTL16 was mainly distributed in the hemolymph. TcCTL16 was significantly upregulated after challenges with lipopolysaccharides, peptidoglycans, Escherichia coli, and Staphylococcus aureus. Recombinant CRDs of TcCTL16 bind directly to the tested bacteria (except Bacillus subtilis); they also induce extensive bacterial agglutination in the presence of Ca2+. On the contrary, after TcCTL16 silencing in the late larval stage, T. castaneum were able to develop normally. Moreover, the transcript levels of seven antimicrobial peptide genes (attacin2, defensins1, defensins2, coleoptericin1, coleoptericin2, cecropins2, and cecropins3) and one transcription factor gene (relish) were significantly increased under E. coli challenge and led to an increased survival rate of T. castaneum when infected with S. aureus or E. coli, suggesting that TcCTL16 deficiency could be compensated for by increasing AMP expression via the IMD pathways in T. castaneum. In conclusion, this study found that TcCTL16 could be involved in developmental regulation in early larvae and compensate for the loss of CTL function by regulating the expression of AMPs in late larvae, thus laying a solid foundation for further studies on T. castaneum CTLs.

IKKβ regulates antimicrobial innate immune responses in the yellow mealworm, Tenebrio molitor

Toll and IMD pathways regulate antimicrobial innate immune responses in insect model systems. The transcriptional activation of antimicrobial peptides (AMPs) confers humoral immunity in the host against invaded pathogens. The IKK kinase complex (IKKα, IKKβ, and the regulatory subunit IKKγ/NEMO) centrally regulates the NF-κB response to various stimuli. It triggers an appropriate antimicrobial immune response in the host. In this study, a TmIKKβ (or TmIrd5) homolog was screened from the RNA-seq database of the coleopteran beetle, Tenebrio molitor. A single exon characterizes the TmIKKβ gene, and the open reading frame (ORF) comprises of 2112 bp that putatively encodes a polypeptide of 703 amino acid residues. TmIKKβ contains a serine/threonine kinase domain and is phylogenetically close to Tribolium castaneum IKKβ homolog (TcIKKβ). TmIKKβ transcripts were highly expressed in the early pupal (P1) and adult (A5) stages. Among the tissues, TmIKKβ showed higher expression in the integument of the last instar larvae and the fat body and hemocytes of 5-day-old adults. TmIKKβ mRNA was upregulated post-E. coli challenge to the host. Moreover, RNAi-based TmIKKβ mRNA silencing increased host larvae’ susceptibility against E. coli, S. aureus and C. albicans. TmIKKβ RNAi in the fat body led to a downregulation in mRNA expression of ten out of fourteen AMP genes, including TmTenecin1, -2, and -4; TmDefensin, and -like; TmColeoptericinA, and -B; and TmAttacin1a, -1b, and -2, suggesting the requirement of the gene in antimicrobial innate immune responses. Further, a decrease in the mRNA expression of NF-κB factors such as TmRelish, TmDorsal1, and TmDorsal2 in the fat body of T. molitor larvae was observed post-microorganisms challenge. Thus, TmIKKβ regulates antimicrobial innate immune responses in T. molitor.

Effects of embryonic thermal manipulation on the immune response to post-hatch Escherichia coli challenge in broiler chicken.

Thermal manipulation (TM), exposure to mild heat shock during embryogenesis, which is a critical developmental period of broiler chickens, improves tissue stability, oxidative stress response, and immune response during heat stress. Thermal manipulation could be more cost-effective than other methods to boost the immune response. This study aimed to evaluate the impact of TM during embryogenesis, concomitant with an Escherichia coli challenge, on body weight (BW), body temperature (Tb), and splenic mRNA expression of cytokines (Interleukin [IL]-1β, IL-2, IL-6, IL-8, IL-12, IL-15, IL-16, IL-18, and interferon [IFN]-γ) in poultry. A total of 740 fertile eggs were procured from a certified Ross broiler breeder. The eggs were divided into two incubation groups: the control and TM groups. The eggs in the control group were kept at 37.8°C air temperature and 56% relative humidity (RH) during incubation; eggs of the TM group were incubated under standard conditions, except for embryonic days 10-18, during which they were incubated at 39°C and 65% RH for 18 h daily. On the 7th day of incubation, eggs with dead embryos were excluded. After hatching was complete, each group was further subdivided into saline-treated or E. coli-challenged groups. The E. coli (serotype 078 with the dose of 1.5 × 105 colony-forming unit/mL) challenge was performed when the birds were 20 days old. Body weight and Tb measurements were taken on post-hatch days 20, 21, 23, and 25. Splenic mRNA expression of cytokines (IL-1β, IL-2, IL-6, IL-8, IL-12, IL-15, IL-16, IL-18, and IFN-γ) was analyzed by real-time quantitative polymerase chain reaction. Following the E. coli challenge, the TM-treated group's body performance parameters (BW and Tb) were significantly increased compared with the control group. Body weight was higher in the TM group than in the control group (p < 0.05); Tb was lower in the TM group than in the control group (p < 0.05). The mRNA levels of IL and IFN-γ were more stable and moderately induced in the TM group compared with the control group. Thermal manipulation altered the basal mRNA levels of ILs and IFN-γ and changed their expression dynamics after the E. coli challenge. Thermal manipulation during embryogenesis could boost the immune system response to E. coli.

Effect of different ratios of phytogenic feed additives on growth performance, nutrient digestibility, intestinal barrier integrity, and immune response in weaned pigs challenged with a pathogenic Escherichia coli.

This study was conducted to investigate the effects of supplementing different ratios of phytogenic feed additives (PFA) to weaned pigs challenged with pathogenic Escherichia coli on growth performance, nutrient digestibility, intestinal barrier integrity, and immune response, and to determine the optimal mixing ratio for post-weaning diarrhea (PWD) prevention. A total of 48 4-wk-old weaned pigs with initial body weight of 8.01 ± 0.39 kg were placed in individual metabolic cages, and then randomly assigned to eight treatment groups. The eight treatments were as follows: a basal diet without E. coli challenge (negative control, NC), a basal diet with E. coli challenge (positive control, PC), PC with supplementing 0.1% mixture of 20% bitter citrus extract (BCE), 10% microencapsulated blend of thymol and carvacrol (MEO), and 70% excipient (T1), PC with supplementing 0.1% mixture of 10% MEO, 20% premixture of grape seed and grape marc extract, green tea, and hops (PGE), and 60% excipient (T2), PC with supplementing 0.1% mixture of 10% BCE, 10% MEO, 10% PGE, and 70% excipient (T3), PC with supplementing 0.1% mixture of 20% BCE, 20% MEO, and 60% excipient (T4), PC with supplementing 0.1% mixture of 20% MEO, 20% PGE, and 60% excipient (T5), and PC with supplementing 0.1% mixture of 10% BCE, 20% MEO, 10% PGE, and 60% excipient (T6). The experiments progressed in 16 days, including 5 days before and 11 days after the first E. coli challenge (day 0). In the E. coli challenge treatments, all pigs were orally inoculated by dividing a total of 10 mL of E. coli F 18 for three consecutive days from day 0 postinoculation (PI). Compared with the PC group, the PFA2 and PFA6 groups significantly increased (P < 0.05) feed efficiency and decreased (P < 0.05) diarrhea during the entire period. At day 11 PI, the PFA6 group significantly improved (P < 0.05) gross energy digestibility compared to the PFA1 group. The PFA6 group significantly decreased (P < 0.05) tumor necrosis factor α (TNF-α) and interleukin-6 in serum and increased (P < 0.05) the villus height to crypt depth ratio (VH:CD). The PFA2 significantly decreased (P < 0.05) the relative protein expression of calprotectin in the ileum. In conclusion, improvements in growth performance, diarrhea reduction, and immunity enhancement are demonstrated when 10% BCE, 20% MEO, 10% PGE, and 60% excipient are mixed.

Probiotic Debaryomyces hansenii CBS 8339 yeast enhanced immune responses in mice.

This study aimed to examine the effect of Debaryomyces hansenii CBS 8339 on innate immune responses in mice. Thirty BALB/c mice were randomly treated with phosphate buffered saline (PBS) (control) and two D. hansenii (Dh) doses: Dh 10ˆ6 CFU (colony forming units) and Dh 10ˆ8 CFU daily for 15days. Spleen, blood, and gut samples were taken on days7 and 15. Mouse splenocytes were isolated and challenged with Escherichia coli. Immunological assays and immune-related gene expressions were performed. Serum was obtained from blood for total IgA and IgG antibody titer determination. Gut samples were taken for yeast colonization assessment. Phagocytosis, respiratory burst activity, and nitric oxide production in mice were mainly enhanced (p < 0.05) upon 7days of D. hansenii intake at a concentration of 10ˆ8 CFU before and after bacterial challenge. Moreover, oral D. hansenii in mice upregulated (p < 0.05) gene expression of pro-inflammatory cytokines (INF-γ, IL-6 and IL-1β) before or after E. coli challenge on day7 but downregulated (p < 0.05) on day15. Furthermore, total serum IgG and IgA titers were higher (p < 0.05) in Dh 10ˆ8 CFU at days7 and 15, and only at day7, respectively, than that in the other dose and control groups. Finally, D. hansenii was detected in the gut of mice that received the treatments, suggesting that yeast survived gastrointestinal transit. Altogether, a short period (7days) of D. hansenii CBS 8339 oral delivery improved immune innate response on mice.

Effects of Dietary Copper and Escherichia coli Challenge on the Immune Response and Gill Oxidative Balance in the Freshwater Mussel Diplodon chilensis.

Copper is a water and sediment pollutant that can be biomagnified by phytoplankton, and it often co-occurs with fecal bacteria. We addressed the combined effects of copper and Escherichia coli on the immune response and gill oxidative balance of the freshwater mussel Diplodon chilensis. Bivalves were sorted into four groups fed with 1) control algae, 2) bacteria (E. coli), 3) copper-enriched algae (Cu2+ ) algae, and 4) copper-enriched algae followed by bacteria (Cu2+ + E. coli). Cellular and humoral immune and cytotoxic variables were analyzed in hemolymph, and detoxifying/antioxidant enzyme activities (glutathione S-transferase [GST] and catalase [CAT]) and lipid peroxidation (thiobarbituric acid reactive substances [TBARS]) were studied in gill tissue. The total hemocyte number increased after Cu2+ exposure, independently of the E. coli challenge. The proportion of hyalinocytes significantly diminished in the E. coli and Cu2+ groups but not in Cu2+ + E. coli groups; granulocytes significantly increased with E. coli but not with Cu2+ + E. coli treatments. Phagocytic activity was higher in all treatments than in control mussels. Acid phosphatase activity was increased by E. coli and inhibited by Cu2+ and Cu2+ + E. coli. Both E. coli and Cu2+ but not Cu2+ + E. coli augmented alkaline phosphatase activity. The Cu2+ and Cu2+ + E. coli treatments reduced the lysosomal membrane stability and cell viability. Humoral bacteriolytic and phenol oxidase activities were not affected by any treatment. The Cu2+ treatment induced gill CAT and GST activities and increased TBARS levels. The Cu2+ + E. coli treatment reversed this CAT and GST stimulation and increased the Cu2+ effect on TBARS. Dietary Cu2+ affects bivalves' immunological and oxidative status and impairs defensive responses against bacteria. In turn, E. coli potentiates the gill oxidative effects of Cu2+ . Environ Toxicol Chem 2023;42:154-165. © 2022 SETAC.

PSX-B-14 Effects of Adding Protected Benzoic Acid on Growth Performance, Diarrhea, and Inflammation in Weaned Pigs Challenged with Escherichia Coli F18

Abstract This experiment quantified the impact of an E. coli challenge and evaluated protected benzoic acid (PBA) as the alternative to recover growth performance, diarrhea, and inflammation of weaned pigs. A total of 72 pigs (BW=6.07±0.66kg) were housed in pens (2 pigs/pen) and randomly assigned to 1 of 3 treatments (12 pens/treatment). Treatments included a non-challenged control (NC), a challenged-control experimentally infected with F18 E. coli (PC), and PC plus 0.25% PBA (Novus international St. Charles, MO). The experiment lasted 18 days, with 7 days of acclimation and 11 days post-infection (dpi). Blood samples were collected at 0, 4, and 11 dpi. Data were analyzed using the MIXED procedure of SAS. At the end of the experiment (11 dpi), pigs on NC were heavier than those in the PC, whereas pigs fed PBA were intermediate (9.43, 8.22, and 8.75kg, respectively; P = 0.026). For the entire experimental period (-7 to 11 dpi) pigs on the NC had increased ADG compared with PC and PBA (0.196, 0.105, and 0.127kg, respectively; P=0.019). Pigs on the NC had increased ADFI compared with PC, whereas PBA was intermediate (0.244, 0.167, and 0.204kg, respectively; P=0.011). G:F tended to differ among treatments (P=0.070): the NC had the greatest G:F followed by PBA and NC (0.800, 0.565, 0507, respectively). Diarrhea incidence was decreased in the NC compared with PC and PBA (22.9, 44.2, and 52.1%, respectively; P=0.01). Serum acute-phase C reactive protein (CRP), a marker of systemic inflammation, tended to differ among treatments (P=0.076): the PC had the greatest CRP concentration followed by PBA and NC (3,841, 2,243, and 2,106 ng/mL, respectively). In conclusion, the E. coli infection impacted the growth and health of weaned pigs; however, the addition of PBA partially alleviated the negative effects by stimulating feed intake, growth, and decreasing systemic inflammation.

244 Application of the Escherichia Coli Challenge Model in Developing Strategies to Improve gut Health and Function in Weaned Pigs

Abstract Post-weaning diarrhea in piglets, caused primarily by enterotoxigenic Escherichia coli is a major cause of productive and economic losses to the swine industry. Traditionally, the swine industry has managed this disease by utilizing starter diets containing highly digestible and specialized ingredients such as spray-dried porcine plasma and sub-therapeutic levels of antibiotics as growth promoters. However, there has intense public pressure to discontinue the use of animal products and antibiotics in pig diets for fear that these products represent a risk to human health. This has sparked great interest in swine nutrition is to identify effective, safe, and environmentally friendly nutritional interventions that could be used in place of in-feed antibiotics. This requires that any such intervention is rigorously tested under conditions that represent those that are encountered in production settings. To this end, the Escherichia coli K88 (or F4) disease challenge model has been used to test the potential of these interventions to support gut health and function in piglets and to allow investigations into the mode of action underlying any such effects. Although this model has been applied successfully to examine the efficacy of different nutritional interventions, including diet formulation strategies and addition of various feed additives, the degree of success achieved varies due to among other factors such as dose used, age of the pigs, and study duration. Being a disease challenge model, animal care oversight, regulatory requirements for Containment Level II facilities, and trial site managements to avoid cross-contamination among treatment groups add to the complexity of protocols for running trials involving this model. Nonetheless, the enterotoxigenic Escherichia coli model has been an effective tool in our hands to test the efficacy of various nutritional interventions in protecting piglets against post-weaning diarrhea disease and to elucidate their modes of action.

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

BackgroundThis 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).ResultsA total of 63 4-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 factor α was 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 down-regulated (P < 0.05) the expression of calprotectin compared to the PC treatment.ConclusionsSupplementation 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.

Construction of the waaF Subunit and DNA Vaccine Against Escherichia coli in Cow Mastitis and Preliminary Study on Their Immunogenicity.

Escherichia coli (E. coli) is one of the major pathogenic bacteria in bovine mastitis, which usually triggers systemic symptoms by releasing lipopolysaccharide (LPS). waaF is the core in LPS pathogenicity. In this study, a new waaF vaccine candidate was identified, constructed with the pcDNA3.1 (+)HisB-waaF plasmid to create to a DNA vaccine (pcwaaF), and transfected into MCF-7 cells to produce recombinant waaF subunit vaccine (rwaaF). After that, the safety of the two vaccine candidates was evaluated in mouse model. Immunogenicity and mortality of challenged mice were compared in 20 and 40 μg per dose, respectively. The results showed that rwaaF and pcwaaF were successfully constructed and the complete blood count and serum biochemical indicated that both of the vaccine candidates were safe (p > 0.05). In addition, histopathological staining showed no obvious pathological changes. The immune response induced by rwaaF was significantly higher than that of pcwaaF (p < 0.01), indicated by levels of serum concentration of IgG IL-2, IL-4, and IFN-γ, and feces concentration of sIgA. Survival rates of mice in rwaaF groups (both 80%) were also higher than in the pcwaaF groups (40 and 50%, respectively). Comparing the safety, immunogenicity, and E. coli challenge of two vaccine candidates, rwaaF had the better effect and 20 μg rwaaF was more economical. In conclusion, this study demonstrates the utility of a new E. coli vaccine and provides a rationale for further investigation of bovine mastitis therapy and management.