154 research outputs found

    Analysis of chicken intestinal natural killer cells, a major IEL subset during embryonic and early life

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    Restrictions on antimicrobials demand alternative strategies to improve broiler health, such as supplying feed additives which stimulate innate immune cells like natural killer (NK) cells. The main objective of this study was to characterize intestinal NK cells in broiler chickens during embryonic and early life and compare these to NK cells in spleen, blood and bone marrow. Also T-cell subsets were determined. The majority of intestinal NK cells expressed IL-2Rα rather than 20E5 and 5C7, and showed low level of activation. Within intestinal NK cells the activation marker CD107 was mostly expressed on IL-2Rα+ cells while in spleen and blood 20E5+ NK cells primarily expressed CD107. High percentages of intestinal CD8αα+, CD8αβ+ and from 2 weeks onward also gamma delta T cells were found. Taken together, we observed several intestinal NK subsets in broiler chickens. Differences in NK subsets were mostly observed between organs, rather than differences over time. Targeting these intestinal NK subsets may be a strategy to improve immune-mediated resistance in broiler chickens.SUPPLEMENTARY MATERIAL : Table S1. Characterization of immune cells generated in broiler chickens in the present study compared to data known in layer chickens.The Dutch Research Council (NWO) and by Cargill Animal Nutrition and Health.http://www.elsevier.com/locate/desalhj2022Veterinary Tropical Disease

    Conserved developmental trajectories of the cecal microbiota of broiler chickens in a field study

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    There is great interest in identifying gut microbiota development patterns and underlying assembly rules that can inform strategies to improve broiler health and performance. Microbiota stratification using community types helps to simplify complex and dynamic ecosystem principles of the intestinal microbiota. This study aimed to identify community types to increase insight in intestinal microbiota variation between broilers and to identify factors that explain this variation. A total of 10 well-performing poultry flocks on four farms were followed. From each flock, the cecal content of nine broilers was collected at 7, 14, and 35 days posthatch. A total of two robust community types were observed using different clustering methods, one of which was dominated by 7-day-old broilers, and one by 35-day-old broilers. Broilers, 14-day-old, were divided across both community types. This is the first study that showed conserved cecal microbiota development trajectories in commercial broiler flocks. In addition to the temporal development with age, the cecal microbiota variation between broilers was explained by the flock, body weight, and the different feed components. Our data support a conserved development of cecal microbiota, despite strong influence of environmental factors. Further investigation of mechanisms underlying microbiota development and function is required to facilitate intestinal health promoting management, diagnostics, and nutritional interventions

    A detailed analysis of innate and adaptive immune responsiveness upon infection with Salmonella enterica serotype Enteritidis in young broiler chickens

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    Salmonella enterica serotype Enteritidis (SE) is a zoonotic pathogen which causes foodborne diseases in humans as well as severe disease symptoms in young chickens. More insight in innate and adaptive immune responses of chickens to SE infection is needed to understand elimination of SE. Seven-day-old broiler chickens were experimentally challenged with SE and numbers and responsiveness of innate and adaptive immune cells as well as antibody titers were assessed. SE was observed in the ileum and spleen of SE-infected chickens at 7 days post-infection (dpi). At 1 dpi numbers of intraepithelial cytotoxic CD8+ T cells were signifcantly increased alongside numerically increased intraepithelial IL-2Rα+ and 20E5+ natural killer (NK) cells at 1 and 3 dpi. At both time points, activation of intraepithelial and splenic NK cells was signifcantly enhanced. At 7 dpi in the spleen, presence of macrophages and expression of activation markers on dendritic cells were signifcantly increased. At 21 dpi, SE-induced proliferation of splenic CD4+ and CD8+ T cells was observed and SE-specifc antibodies were detected in sera of all SE-infected chickens. In conclusion, SE results in enhanced numbers and activation of innate cells and we hypothesized that in concert with subsequent specifc T cell and antibody responses, reduction of SE is achieved. A better understanding of innate and adaptive immune responses important in the elimination of SE will aid in developing immune-modulation strategies, which may increase resistance to SE in young broiler chickens.ADDITIONAL FILE 1. Gating strategy of IELs and splenic lymphocytes in broiler chickens. Gating strategy included consecutive selection for lymphocytes (FSC-A vs SSC-A), singlets (FSC-A vs FSC-H) and viable cells (Live/Dead marker-negative) followed by selection of NK and T cell subsets in ileum and spleen. Furthermore, activation of NK and T cells was analyzed by surface expression of CD107 and intracellular expression of IFNγ. Conjugate controls are shown for IELs and splenic lymphocytes.ADDITIONAL FILE 2. Effect of SE infection on numbers of splenic NK cells in broiler chickens. A Numbers (cells/mg) of splenic IL-2Rα+ and B 20E5+ NK cells per mg spleen in uninfected (uninf) and SE-infected (SE-inf) chickens in the course of time. C Gene expression levels of NK cell lineage marker (NFIL3), IL-7Rα and perforin 1 (PRF1) by RT-qPCR in sorted IL-2Rα+ and 20E5+ NK cell subsets. Mean + SEM per treatment and time point is shown (n = 5), for uninfected chickens at 7 dpi n = 4 and for gene expression levels n = 1.ADDITIONAL FILE 3. Staining and sorting controls associated with Figure 4. A The staining controls for the gating strategy are shown. The left panel depicts splenocytes without the viability dye. The middle and right panels show splenocytes that are gated according to Figure 4A, but without the primary antibodies that bind MRC1LB and CD11, respectively. B The graphs show the gating strategy and purity of a representative sample of splenocytes that was sorted into CD11+ MRC1LB+, CD11+ MRC1LB− FSClow and CD11+ MRC1LB− FSChigh subpopulations. The splenocytes that are gated as CD11+ MRC1LB− in the upper panels are shown in the lower panels to visualize their FSC-A vs SSC-A pattern. C The absolute numbers of sorted APC subpopulations are shown.ADDITIONAL FILE 4. Phenotypic characterization of splenic APCs upon SE infection. A-B The presence (%) and C-D numbers (cells/mg spleen) of FSClow DCs and and FSChigh DCs in uninfected (uninf) and SE-infected (SE-inf) chickens were assessed over time. Mean + SEM per treatment and time point is shown (n = 5), for uninfected chickens at 0 dpi n = 3 and at 7 dpi n = 4. Statistical significance is indicated as ** p < 0.01.ADDITIONAL FILE 5. The gating strategy used to determine the activation status of the APC subsets as depicted in Figure 5. The three identified splenic APC subsets A macrophages, B FSClow DCs and C FSChigh DCs were assessed for CHIR-AB1, CD40, CD80 and MHC-II. For CHIR-AB1, CD40 and CD80, the cells expressing the respective markers were selected and expressed as a percentage. The expression of MHC-II by each subset was expressed as the geometric mean fluorescent intensity (gMFI).ADDITIONAL FILE 6. Numbers of intraepithelial and splenic γδ T cells and cytotoxic T cells expressing either CD8αα or CD8αβ in broiler chickens upon SE infection. A Numbers (cells/mg) of intraepithelial CD8αα+ γδ T cells, B CD8αβ+ γδ T cells, C cytotoxic CD8αα+ T cells and D CD8αβ+ T cells per mg ileum in uninfected (uninf) and SE-infected (SE-inf) chickens in the course of time. E Numbers (cells/mg) of splenic CD8αα+ γδ T cells, F CD8αβ+ γδ T cells, G cytotoxic CD8αα+ T cells and H CD8αβ+ T cells per mg spleen in uninfected and SE-infected chickens. Mean + SEM per treatment and time point is shown (n = 5), for uninfected chickens at 1 dpi in the IELs and spleen n = 4 due to numbers of events acquired in the gate of interest were < 100, and at 7 dpi in spleen n = 4. Statistical significance is indicated as * p < 0.05, ** p < 0.01. *** p < 0.001.ADDITIONAL FILE 7. Numbers of CD4 + T cells in the spleen of broiler chickens upon SE infection. Numbers (cells/mg) of splenic CD4+ αβ T cells per mg spleen in uninfected (uninf) and SE-infected (SE-inf) chickens in the course of time. Mean + SEM per treatment and time point is shown (n = 5), for uninfected chickens at 7 dpi n = 4.ADDITIONAL FILE 8. T cell activation in the IEL population and spleen of broiler chickens upon SE infection. A Percentages of intraepithelial CD8+ T cells expressing CD107 (including both γδ and αβ T cells) in uninfected (uninf) and SE-infected (SE-inf) chickens in the course of time. B Percentages of splenic CD8+ T cells expressing CD107 (including both γδ and αβ T cells), C CD8+ γδ T cells expressing IFNγ, D CD4+ αβ T cells expressing IFNγ and E CD8+ αβ T cells expressing IFNγ in uninfected (uninf) and SE-infected (SE-inf) chickens over time. Mean + SEM per treatment and time point is shown (n = 5), for uninfected chickens at 7 dpi in spleen n = 4 and at 1 and 3 dpi in the IELs percentages were not determined (n.d.) due to numbers of events acquired in the gate of interest were < 100.The Dutch Research Council (NWO) and by Cargill Animal Nutrition and Health.http://www.veterinaryresearch.orgpm2022Veterinary Tropical Disease

    Comparing farm biosecurity and antimicrobial use in high-antimicrobial-consuming broiler and pig farms in the Belgian-Dutch border region

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    As antimicrobial resistance is a worldwide problem, threatening both livestock and public health, understanding the drivers for resistance in different settings and countries is essential. Therefore, 30 pig and 30 poultry farms with country-specific high antimicrobial use (AMU) were recruited in the Belgian-Dutch border region. Information regarding production parameters, farm characteristics, biosecurity, and AMU was collected. On average, more biosecurity measures were implemented on Dutch farms, compared to Belgian farms in both animal species. In addition, more opportunities were found to increase the level of internal biosecurity compared to external biosecurity in both countries. AMU, quantified as treatment incidence (TI), differed marginally significant between broiler farms in Belgium and the Netherlands (median BE: 8; NL: 3), whereas in weaned piglets (median BE: 45 and NL: 14) and finishing pigs (median BE: 5 and NL: 1), there was a substantial difference in AMU between farms from both countries. Overall, Dutch farms showed less between-farm variation in TI than did Belgian farms. In both poultry and pig production, the majority of antimicrobials used were extended-spectrum penicillins (BE: 32 and 40%; NL: 40 and 24% for poultry and pigs, respectively). Compared to Belgian farms, Dutch poultry farms used high amounts of (fluoro)quinolones (1 and 15% of total AMU, respectively). None of the production parameters between broiler farms differed significantly, but in pig production, weaning age in Belgian farms (median: 23) was lower than in Dutch farms (median: 27). These results indicate considerable room for improvement in both countries and animal species. Farm-specific preventive strategies can contribute to lowering the risk for animal disease and hence the need for AMU

    Does having a cat in your house increase your risk of catching COVID-19?

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    [EN]Due to the zoonotic origin of SARS-Coronavirus 2 (SARS-CoV-2), the potential for its transmission from humans back to animals and the possibility that it might establish ongoing infection pathways in other animal species has been discussed. Cats are highly susceptible to SARS-CoV-2 and were shown experimentally to transmit the virus to other cats. Infection of cats has been widely reported. Domestic cats in COVID-19-positive households could therefore be a part of a human to animal to human transmission pathway. Here, we report the results of a qualitative risk assessment focusing on the potential of cat to human transmission in such settings. The assessment was based on evidence available by October 2021. After the introduction of SARS-CoV-2 to a household by a human, cats may become infected and infected cats may pose an additional infection risk for other members of the household. In order to assess this additional risk qualitatively, expert opinion was elicited within the framework of a modified Delphi procedure. The conclusion was that the additional risk of infection of an additional person in a household associated with keeping a domestic cat is very low to negligible, depending on the intensity of cat-to-human interactions. The separation of cats from humans suffering from SARS-CoV-2 infection should contribute to preventing further transmission.SIThis work was funded by the German Federal Ministry of Education and Research within the COVMon Project, being part of the InfectControl2020 Initiative (BMBF grant no. 03COV16D)

    CD27(+)CD38(hi) B Cell Frequency During Remission Predicts Relapsing Disease in Granulomatosis With Polyangiitis Patients

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    Background: Granulomatosis with polyangiitis (GPA) patients are prone to disease relapses. We aimed to determine whether GPA patients at risk for relapse can be identified by differences in B cell subset frequencies. Methods: Eighty-five GPA patients were monitored for a median period of 3.1 years (range: 0.1-6.3). Circulating B cell subset frequencies were analyzed by flow cytometry determining the expression of CD19, CD38, and CD27. B cell subset frequencies at the time of inclusion of future-relapsing (F-R) and non-relapsing (N-R) patients were compared and related to relapse-free survival. Additionally, CD27(+)CD38(hi) B cells were assessed in urine and kidney biopsies from active anti-neutrophil cytoplasmic autoantibody-associated vasculitides (AAV) patients with renal involvement. Results: Within 1.6 years, 30% of patients experienced a relapse. The CD27(+)CD38(hi) B cell frequency at the time of inclusion was increased in F-R (median: 2.39%) compared to N-R patients (median: 1.03%; p = 0.0025) and a trend was found compared with the HCs (median: 1.33%; p = 0.08). This increased CD27(+)CD38(hi) B cell frequency at inclusion was correlated to decreased relapse-free survival in GPA patients. In addition, 74.7% of patients with an increased CD27(+)CD38(hi) B cell frequency (>= 2.39%) relapsed during follow-up compared to 19.7% of patients with a CD27(+)CD38(hi) B cell frequency of Conclusions: Our data suggests that having an increased frequency of circulating CD27(+)CD38(hi) B cells during remission is related to a higher relapse risk in GPA patients, and thereforemight be a potentialmarker to identify those GPA patients at risk for relapse

    Glucose oligosaccharide and long-chain glucomannan feed additives induce enhanced activation of intraepithelial NK cells and relative abundance of commensal lactic acid bacteria in broiler chickens

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    Restrictions on the use of antibiotics in the poultry industry stimulate the development of alternative nutritional solutions to maintain or improve poultry health. This requires more insight in the modulatory effects of feed additives on the immune system and microbiota composition. Compounds known to influence the innate immune system and microbiota composition were selected and screened in vitro, in ovo, and in vivo. Among all compounds, 57 enhanced NK cell activation, 56 increased phagocytosis, and 22 increased NO production of the macrophage cell line HD11 in vitro. Based on these results, availability and regulatory status, six compounds were selected for further analysis. None of these compounds showed negative effects on growth, hatchability, and feed conversion in in ovo and in vivo studies. Based on the most interesting numerical results and highest future potential feasibility, two compounds were analyzed further. Administration of glucose oligosaccharide and long-chain glucomannan in vivo both enhanced activation of intraepithelial NK cells and led to increased relative abundance of lactic acid bacteria (LAB) amongst ileum and ceca microbiota after seven days of supplementation. Positive correlations between NK cell subsets and activation, and relative abundance of LAB suggest the involvement of microbiota in the modulation of the function of intraepithelial NK cells. This study identifies glucose oligosaccharide and longchain glucomannan supplementation as effective nutritional strategies to modulate the intestinal microbiota composition and strengthen the intraepithelial innate immune system.The Dutch Research Council (NWO) in conjunction with Cargill Animal Nutrition and Health in the context of stimulating Public–Private research collaboration and part of the research program of NWO Earth and Life Sciences (ALW).http://www.mdpi.com/journal/vetscipm2022Veterinary Tropical Disease

    Clinical and Pathological Findings in SARS-CoV-2 Disease Outbreaks in Farmed Mink (Neovison vison)

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    SARS-CoV-2, the causative agent of COVID-19, caused respiratory disease outbreaks with increased mortality in 4 mink farms in the Netherlands. The most striking postmortem finding was an acute interstitial pneumonia, which was found in nearly all examined mink that died at the peak of the outbreaks. Acute alveolar damage was a consistent histopathological finding in mink that died with pneumonia. SARS-CoV-2 infections were confirmed by detection of viral RNA in throat swabs and by immunohistochemical detection of viral antigen in nasal conchae, trachea, and lung. Clinically, the outbreaks lasted for about 4 weeks but some animals were still polymerase chain reaction–positive for SARS-CoV-2 in throat swabs after clinical signs had disappeared. This is the first report of the clinical and pathological characteristics of SARS-CoV-2 outbreaks in mink farms

    Evaluating Surveillance Strategies for the Early Detection of Low Pathogenicity Avian Influenza Infections

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    In recent years, the early detection of low pathogenicity avian influenza (LPAI) viruses in poultry has become increasingly important, given their potential to mutate into highly pathogenic viruses. However, evaluations of LPAI surveillance have mainly focused on prevalence and not on the ability to act as an early warning system. We used a simulation model based on data from Italian LPAI epidemics in turkeys to evaluate different surveillance strategies in terms of their performance as early warning systems. The strategies differed in terms of sample size, sampling frequency, diagnostic tests, and whether or not active surveillance (i.e., routine laboratory testing of farms) was performed, and were also tested under different epidemiological scenarios. We compared surveillance strategies by simulating within-farm outbreaks. The output measures were the proportion of infected farms that are detected and the farm reproduction number (Rh). The first one provides an indication of the sensitivity of the surveillance system to detect within-farm infections, whereas Rh reflects the effectiveness of outbreak detection (i.e., if detection occurs soon enough to bring an epidemic under control). Increasing the sampling frequency was the most effective means of improving the timeliness of detection (i.e., it occurs earlier), whereas increasing the sample size increased the likelihood of detection. Surveillance was only effective in preventing an epidemic if actions were taken within two days of sampling. The strategies were not affected by the quality of the diagnostic test, although performing both serological and virological assays increased the sensitivity of active surveillance. Early detection of LPAI outbreaks in turkeys can be achieved by increasing the sampling frequency for active surveillance, though very frequent sampling may not be sustainable in the long term. We suggest that, when no LPAI virus is circulating yet and there is a low risk of virus introduction, a less frequent sampling approach might be admitted, provided that the surveillance is intensified as soon as the first outbreak is detected
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