Application of imaging flow cytometry for characterization of acute inflammation in non-classical animal model systems

Early-life β-glucan exposure enhances disease resilience of broiler chickens to a natural Clostridium perfringens infection

Necrotic enteritis (NE) is an economically important disease in poultry. Colonization by the opportunistic pathogen C. perfringens occurs early after hatch and induces host immune tolerance, which allows it to persist as part of the bird's commensal microflora. β-glucan, a yeast cell wall component, is well characterized for its immunomodulatory capacity, and is a strong driver of innate immune memory. In this study, we assessed the effectiveness of β-glucan to reduce severity of NE, when co-administered with heat-killed C. perfringens via intra-abdominal route at day 1 of age. We found that this early-life exposure in the presence of β-glucan did not reduce intestinal C. perfringens loads or lesion severity during a subsequent NE outbreak. However, it improved ileal morphology, prevented liver and spleen weight decline, and preserved feed efficiency in challenged birds. Molecular analyses revealed metabolic changes consistent with innate immune memory. Together, our results suggest that β-glucan can reduce the negative impacts of NE by influencing the context in which C. perfringens is first encountered.

Differential Effects of Drinking Water Quality on Phagocyte Responses of Broiler Chickens Against Fungal and Bacterial Challenges

Combinatorial effects of xenobiotics in water on health may occur even at levels within current acceptable guidelines for individual chemicals. Herein, we took advantage of the sensitivity of the immune system and an avian animal model to examine the impact of xenobiotic mixtures on animal health. Water was derived from an underground well in Alberta, Canada and met guidelines for consumption, but contained a number of contaminants. Changes to chicken immunity were evaluated following acute (7d) exposure to contaminated water under basal and immune challenged conditions. An increase in resident macrophages and a decrease in CD8+ lymphocytes were identified in the abdominal cavity, which served as a relevant site where immune leukocytes could be examined. Subsequent intra-abdominal immune stimulation detected differential in vivo acute inflammatory responses to fungal and bacterial challenges. Leukocyte recruitment into the challenge site and activation of phagocyte antimicrobial responses were affected. These functional responses paralleled molecular changes in the expression for pro-inflammatory and regulatory genes. In all, this study primarily highlights dysregulation of phagocyte responses following acute (7d) exposure of poultry to contaminated water. Given that production food animals hold a unique position at the interface of animal, environmental and human health, this emphasizes the need to consider the impact of xenobiotic mixtures in our assessments of water quality.

Esteatose hepática altera acúmulo celular em tilápias do Nilo durante aerocistite infecciosa

RESUMO: O presente estudo avaliou a hepatotoxicidade induzida pelo CCl4 durante o efeito glicocorticoide da dexametasona (DEX) na fisiopatologia da reação inflamatória aguda em tilápias do Nilo, Oreochromis niloticus, correlacionando a funcionalidade hepática à cinética de acúmulo celular em aerocistite infecciosa. Para tal, utilizou-se 84 tilápias do Nilo distribuídas em 4 tratamentos: controle, CCl4, DEX e CCl4+DEX. Sendo amostrados 7 animais por tratamento em três períodos, isto é: seis, 24 e 48h após indução de inflamação. Utilizou-se CCl4 em dose única de 0,5mL/kg, via intraperitoneal para causar o transtorno hepático. Para indução da aerocistite utilizou-se inóculo de Aeromonas hydrophila. A dexametasona foi administrada via intramuscular na dose de 2 mg/kg de peso vivo. Os resultados revelaram que quanto maior foi à atividade sérica de aspartato aminotransferase (AST) maior foi a alteração somática do fígado, sendo estes achados inversamente proporcionais ao acúmulo celular no foco inflamatório, demonstrando menor número de células inflamatórias nos animais acometidos com maior grau de distúrbios hepáticos induzidos pelo CCl4. O estudo histopatológico revelou alterações degenerativas transitórias na fase mais aguda, pois os fígados das tilápias revelaram o acúmulo lipídeos nos hepatócitos 6h após administração de CCl4, sendo esta degeneração gordurosa não mais observada nos tempos de 24 e 48h. Contudo, a administração de CCl4 em tilápias do Nilo resultou em degeneração hepática aguda e transitória, caracterizada pelo acúmulo de gordura nos hepatócitos, aumento de AST no sangue e hepatomegalia. Com a disfunção hepática houve comprometimento do recrutamento celular em aerocistite infecciosa, indicando que há participação do fígado na resposta imune inata em peixes.