25 research outputs found

    CD4+CD25+ Regulatory T Cell Ontogeny and Preferential Migration to the Cecal Tonsils in Chickens

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    Thymic CD4+CD25+ cells have regulatory-T-cell-like properties in chickens. This study examined the ontogeny of CD4+CD25+ cells in the thymus and in peripheral compartments in chickens. CD4+CD25+ cells started to appear in the thymus at day 15 of incubation (E15), although at low percentages. Expressed as a percentage of CD4+ cells, CD4+CD25+ cells increased (P<0.01) from 1.7% at E20 to 7.3% at 0 d post-hatch (D0). CD4+CD25+ cells did not appear in the spleen or cecal tonsils of embryos. Expressed as a percentage of CD4+ cells, CD4+CD25+ cells increased (P<0.01) from 0% at D0 to 27% at D1 in cecal tonsils and from 0% at D0 to 11% at D1 in the spleen. Expressed as a percentage of all mononuclear cells, cecal tonsils at D1 had approximately 3.5-fold higher percentage of CD4+CD25+ cells than the spleen at D1. CD4+CD25+ cells from cecal tonsils of chicks at D1 were suppressive. CD4+CD25+ cells from D0 thymus, when injected back into MHC-compatible chicks, migrated to cecal tonsils and lungs and were detected until 10 d post-injection. CD4+CD25+ cells from cecal tonsils had a higher (P = 0.01) relative amount of CCR9 mRNA than CD4+CD25+ cells from the thymus. It could be concluded that in chickens CD4+CD25+ cells migrate from the thymus immediately post-hatch and preferentially colonize the gut associated lymphoid tissues. CD4+CD25+ cells' preferential migration to cecal tonsils is likely directed through the CCR9 pathway in chickens

    Beyond protein synthesis: the emerging role of arginine in poultry nutrition and host-microbe interactions

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    Arginine is a functional amino acid essential for various physiological processes in poultry. The dietary essentiality of arginine in poultry stems from the absence of the enzyme carbamoyl phosphate synthase-I. The specific requirement for arginine in poultry varies based on several factors, such as age, dietary factors, and physiological status. Additionally, arginine absorption and utilization are also influenced by the presence of antagonists. However, dietary interventions can mitigate the effect of these factors affecting arginine utilization. In poultry, arginine is utilized by four enzymes, namely, inducible nitric oxide synthase arginase, arginine decarboxylase and arginine: glycine amidinotransferase (AGAT). The intermediates and products of arginine metabolism by these enzymes mediate the different physiological functions of arginine in poultry. The most studied function of arginine in humans, as well as poultry, is its role in immune response. Arginine exerts immunomodulatory functions primarily through the metabolites nitric oxide (NO), ornithine, citrulline, and polyamines, which take part in inflammation or the resolution of inflammation. These properties of arginine and arginine metabolites potentiate its use as a nutraceutical to prevent the incidence of enteric diseases in poultry. Furthermore, arginine is utilized by the poultry gut microbiota, the metabolites of which might have important implications for gut microbial composition, immune regulation, metabolism, and overall host health. This comprehensive review provides insights into the multifaceted roles of arginine and arginine metabolites in poultry nutrition and wellbeing, with particular emphasis on the potential of arginine in immune regulation and microbial homeostasis in poultry

    Subclinical doses of dietary fumonisins and deoxynivalenol cause cecal microbiota dysbiosis in broiler chickens challenged with Clostridium perfringens

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    Fusarium toxins are one of the most common contaminants in poultry diets. The co-occurrence of fumonisins (FUM) and deoxynivalenol (DON), even at a subclinical dose, negatively affects the growth performance, intestinal integrity and induce subclinical necrotic enteritis in broiler chickens. Loss of gut integrity can be expected to alter the intestinal microbiota’s composition. The objective of this study was to identify the effects of combined FUM and DON on the cecal microbiome profile and predicted metabolic functions and a short chain fatty acid profile in broilers challenged with Clostridium perfringens. A total of 240 1 day-old chicks were randomly assigned to two treatments: a control diet and the control diet with 3 mg/kg FUM + 4 mg/kg DON each with eight replications. All the birds were received cocci vaccine at d0. All birds in both treatment groups were challenged with C. perfringens 1 × 108 CFU via feed on d 19 and 20 to achieve 5% mortality. On d 35, the FUM and DON contaminated diet numerically (P = 0.06) decreased the body weight gain (BWG) by 84 g compared to the control group. The bacterial compositions of the cecal contents were analyzed by sequencing the V3–V4 region of the 16S rRNA gene. Overall, microbial richness and diversity increased (P &lt; 0.02) during the studied period (d 21–35). Cecal contents of birds in the FUM + DON group had greater (P &lt; 0.05) microbial evenness and diversity (Shannon index) compared to the control group. FUM + DON exposure decreased (P = 0.001) the relative abundance of Proteobacteria in the cecal content, compared to the control group. The combined FUM + DON significantly increased the relative abundance of the Defluviitaleaceae and Lachnospiraceae families (P &lt; 0.05) but decreased the abundances of the Moraxellaceae and Streptococcaceae (P &lt; 0.05) compared to the control group birds. At the genus level, FUM + DON exposure decreased (P &lt; 0.05) Acinetobacter and Pseudomonas abundance and had a tendency (P = 0.08) to decrease Thermincola abundance compared to the control group. In the ileum, no NE-specific microscopic abnormalities were found; however, the tip of the ileal villi were compromised. The present findings showed that dietary FUM and DON contamination, even at subclinical levels, altered cecal microbial composition, dysregulated intestinal functions, and impaired the gut immune response, potentially predisposing the birds to necrotic enteritis

    <i>Salmonella</i> Infection in Poultry: A Review on the Pathogen and Control Strategies

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    Salmonella is the leading cause of food-borne zoonotic disease worldwide. Non-typhoidal Salmonella serotypes are the primary etiological agents associated with salmonellosis in poultry. Contaminated poultry eggs and meat products are the major sources of human Salmonella infection. Horizontal and vertical transmission are the primary routes of infection in chickens. The principal virulence genes linked to Salmonella pathogenesis in poultry are located in Salmonella pathogenicity islands 1 and 2 (SPI-1 and SPI-2). Cell-mediated and humoral immune responses are involved in the defense against Salmonella invasion in poultry. Vaccination of chickens and supplementation of feed additives like prebiotics, probiotics, postbiotics, synbiotics, and bacteriophages are currently being used to mitigate the Salmonella load in poultry. Despite the existence of various control measures, there is still a need for a broad, safe, and well-defined strategy that can confer long-term protection from Salmonella in poultry flocks. This review examines the current knowledge on the etiology, transmission, cell wall structure, nomenclature, pathogenesis, immune response, and efficacy of preventative approaches to Salmonella

    Percentage of CD4<sup>+</sup>CD25<sup>+</sup> cells in different organs of developing embryos and post-hatch chicks.

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    <p>Fertile eggs were collected and incubated. At d 15 (E15), 17 (E17), and 20 (E20) of incubation and d 0 (D0), 1 (D1), 2 (D2), and 6 (D6) post-hatch, the thymic lobes, spleens and cecal tonsils were collected and analyzed for CD4<sup>+</sup> and CD4<sup>+</sup>CD25<sup>+</sup> cells. CD4<sup>+</sup>CD25<sup>+</sup> cells were expressed either as a percentage of (A) CD4<sup>+</sup> cells or (B) as a percentage of all mononuclear cells in the sample. a–c, Means (± SD) without a common superscript differ significantly in thymus (<i>P</i><0.05). d–e, Means (± SD) without a common superscript differ significantly in spleen (<i>P</i><0.05). x–z, Means (± SD) without a common superscript differ significantly in cecal tonsils (<i>P</i><0.05). n = 3.</p

    <i>In vivo</i> migratory properties of CD4<sup>+</sup>CD25<sup>+</sup> cells from the thymus of chicks at D0.

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    <p>CD4<sup>+</sup>CD25<sup>+</sup> or CD4<sup>+</sup>CD25<sup>−</sup> cells were collected from the thymus of zero-day-old (D0) chicks, labeled with carboxyfluorescein succinimidyl ester (CFSE), and injected into MHC-compatible chicks. At d 2, 5, and 10 post-injection, the spleen, cecal tonsils (CT), and lungs were analyzed for CFSE<sup>+</sup> cells. a–c, Means (± SD) without a common superscript differ significantly within an organ (<i>P</i><0.05). * indicates significant differences (<i>P</i><0.05) between CFSE<sup>+</sup> cells in the CD4<sup>+</sup>CD25<sup>+</sup> and CD4<sup>+</sup>CD25<sup>−</sup> cells injected groups on a particular day. n = 3.</p

    Suppressive properties of CD4<sup>+</sup>CD25<sup>+</sup> cells from cecal tonsils of chicks at D1.

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    <p>Percentage of non-proliferating responder cells in proliferation suppression assay. CD4<sup>+</sup>CD25<sup>−</sup> responder cells were labeled with carboxyfluorescein succinimidyl ester (CFSE), treated with anti-CD3/CD28, and mixed with effector CD4<sup>+</sup>CD25<sup>+</sup> or CD4<sup>+</sup>CD25<sup>−</sup> cells collected from cecal tonsils of one-day-old chicks at an effector∶responder cell ratio of 1∶1 or 0∶1 (control). At 72 h of co-culture CFSE dilution of CFSE-labeled responder cells was analyzed to calculate non-proliferating cell percentage. Means (+ SD) without a common superscript differ significantly (<i>P</i><0.05). n = 3.</p

    Gastrointestinal Microbiota and Their Manipulation for Improved Growth and Performance in Chickens

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    The gut of warm-blooded animals is colonized by microbes possibly constituting at least 100 times more genetic material of microbial cells than that of the somatic cells of the host. These microbes have a profound effect on several physiological functions ranging from energy metabolism to the immune response of the host, particularly those associated with the gut immune system. The gut of a newly hatched chick is typically sterile but is rapidly colonized by microbes in the environment, undergoing cycles of development. Several factors such as diet, region of the gastrointestinal tract, housing, environment, and genetics can influence the microbial composition of an individual bird and can confer a distinctive microbiome signature to the individual bird. The microbial composition can be modified by the supplementation of probiotics, prebiotics, or synbiotics. Supplementing these additives can prevent dysbiosis caused by stress factors such as infection, heat stress, and toxins that cause dysbiosis. The mechanism of action and beneficial effects of probiotics vary depending on the strains used. However, it is difficult to establish a relationship between the gut microbiome and host health and productivity due to high variability between flocks due to environmental, nutritional, and host factors. This review compiles information on the gut microbiota, dysbiosis, and additives such as probiotics, postbiotics, prebiotics, and synbiotics, which are capable of modifying gut microbiota and elaborates on the interaction of these additives with chicken gut commensals, immune system, and their consequent effects on health and productivity. Factors to be considered and the unexplored potential of genetic engineering of poultry probiotics in addressing public health concerns and zoonosis associated with the poultry industry are discussed
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