Quercetin, the main component of flavonoids, has a wide range of biological actions. Quercetin can be made into a variety of additives for practice, because of the stable chemical structure and water-soluble derivatives. This study was intended to explore the effects of quercetin on immune function and its regulatory mechanism in Arbor Acre broiler to provide a practical basis for improving poultry immune function and figure out the optimum supplementation as functional feed additives. A total of 240 one-day-old healthy Arbor Acre broilers, similar in body weight, were randomly allotted to 4 treatments with 6 replicates, 10 broilers in each replicate and fed with diets containing quercetin at 0, 0.02, 0.04, and 0.06% for 6 wk. Blood and immune organs (spleen, thymus, and bursa) were collected from chickens at the end of the experiment. Growth performance, immune organs indexes, contents of serum immune molecules, splenic T lymphocyte proliferative responses, and expression of immune related genes were evaluated. The results showed that dietary quercetin had no significant effect (P > 0.05) on growth performance of broilers. Compared with control, 0.06% quercetin supplementation in diet significantly increased spleen index and thymus index (P < 0.05). It also increased the secretion of immune molecules including immunoglobulin A (IgA), interleukin-4 (IL-4) (P < 0.001), immunoglobulin M (IgM) (P = 0.007), complement component 4 (C4) (P = 0.001), and tumor necrosis factor-α (TNF-α) (P < 0.05). On the other hand, 0.02% quercetin supplementation significantly increased complement component 3 (C3) (P < 0.05). Additionally, both 0.04 and 0.06% quercetin supplementation significantly increased expression of TNF-α, TNF receptor associated factor-2 (TRAF-2), TNF receptor superfamily member 1B (TNFRSF1B), nuclear factor kappa-B p65 subunit (NF-κBp65), and interferon-γ (IFN-γ) mRNA (P < 0.05), and expression of NF-κB inhibitor-alpha (IκB-α) mRNA were significantly decreased (P < 0.05). Thus, quercetin improved immune function via NF-κB signaling pathway triggered by TNF-α.

中文翻译：

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槲皮素通过激活NF-κB信号通路改善Arbor Acre肉鸡的免疫功能。

槲皮素是类黄酮的主要成分，具有广泛的生物学作用。由于稳定的化学结构和水溶性衍生物，槲皮素可以制成各种添加剂用于实践。本研究旨在探讨槲皮素对阿伯阿克尔肉鸡免疫功能的影响及其调控机制，为提高家禽免疫功能提供实用依据，并为功能性饲料添加剂找到最佳补充。总共将240头体重相似的1日龄健康Arbor Acre肉鸡随机分配给4种处理方法，每组6个重复，每个重复10个肉鸡，并饲喂含0、0.02、0.04和0.06％槲皮素的日粮6周。在实验结束时从鸡中收集血液和免疫器官（脾，胸腺和法氏囊）。评价生长性能，免疫器官指标，血清免疫分子含量，脾T淋巴细胞增殖反应以及免疫相关基因的表达。结果表明，膳食槲皮素对肉鸡的生长性能没有显着影响（P> 0.05）。与对照组相比，饮食中添加0.06％槲皮素可显着提高脾脏指数和胸腺指数（P <0.05）。它还增加了免疫分子的分泌，包括免疫球蛋白A（IgA），白介素4（IL-4）（P <0.001），免疫球蛋白M（IgM）（P = 0.007），补体成分4（C4）（P = 0.001） ）和肿瘤坏死因子-α（TNF-α）（P <0.05）。另一方面，添加0.02％槲皮素可显着增加补体成分3（C3）（P <0.05）。此外，0.04和0。06％槲皮素补充可显着增加TNF-α，TNF受体相关因子2（TRAF-2），TNF受体超家族成员1B（TNFRSF1B），核因子κBp65亚基（NF-κBp65）和干扰素-γ的表达（IFN-γ）mRNA（P <0.05）和NF-κB抑制剂-α（IκB-α）mRNA的表达显着降低（P <0.05）。因此，槲皮素通过TNF-α触发的NF-κB信号通路改善了免疫功能。