β‐carotene is a robust modulator of mucosal barriers, and it can amplify the immunoglobulin A (IgA) response via the retinoic acid (RA)–mediated pathway. We investigated the influence of β‐carotene on intestinal barriers in layer‐type cockerels. In this study, β‐carotene has a positive influence on growth performance and intestinal morphology. β‐carotene remarkably enhanced serum secretory immunoglobulin A (sIgA) levels, jejunal mucosal sIgA, and IgA concentrations. β‐Carotene significantly enhanced mRNA expression levels of IgA, CC chemokine receptor‐9 (CCR9), polymeric immunoglobulin receptor (pIgR), and retinoic acid receptor α (RARα) in the ileal tissues and pIgR in the jejunal tissues. β‐Carotene improves mRNA expression of intestinal barrier‐related proteins including: mucin‐2 (MUC‐2), zonula occludens‐2 (ZO‐2), occludins (OCLN), and zonula occludens‐1 (ZO‐1) in the ileal tissues. Moreover, β‐carotene decreased the levels of Escherichia coli and elevates the levels of Lactobacillus. The results indicate that β‐carotene can promote growth performance and contribute to the gradual development of intestinal barriers in Hyline Brown chicks. This study enriches our knowledge about the effects of β‐carotene on intestinal barrier and highlights a theoretical basis of β‐carotene application in the poultry industry.

中文翻译：

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补充β-胡萝卜素对蛋鸡型公鸡生长性能和肠粘膜屏障的影响。

β-胡萝卜素是粘膜屏障的强大调节剂，它可以通过视黄酸 (RA) 介导的途径放大免疫球蛋白 A (IgA) 反应。我们研究了 β-胡萝卜素对蛋鸡型公鸡肠道屏障的影响。在这项研究中，β-胡萝卜素对生长性能和肠道形态有积极影响。β-胡萝卜素显着提高血清分泌性免疫球蛋白 A (sIgA) 水平、空肠粘膜 sIgA 和 IgA 浓度。β-胡萝卜素显着提高回肠组织中 IgA、CC 趋化因子受体-9 (CCR9)、多聚免疫球蛋白受体 (pIgR) 和视黄酸受体 α (RARα) 以及空肠组织中 pIgR 的 mRNA 表达水平。β-胡萝卜素改善肠屏障相关蛋白的 mRNA 表达，包括：粘蛋白-2 (MUC-2)、zonula occludens-2 (ZO-2)、occludins (OCLN)、和回肠组织中的 zonula occludens-1 (ZO-1)。此外，β-胡萝卜素降低了大肠杆菌的水平并提高了乳酸杆菌的水平。结果表明，β-胡萝卜素可以促进 Hyline Brown 雏鸡的生长性能并促进肠道屏障的逐渐形成。本研究丰富了我们对β-胡萝卜素对肠道屏障影响的认识，并突出了β-胡萝卜素在家禽业应用的理论基础。