The aim of this study was to determine whether and how Zn proteinate with moderate chelation strength (Zn-Prot M) can alleviate heat stress (HS)-induced intestinal barrier function damage of broilers. A completely randomized design was used for comparatively testing the effects of Zn proteinate on HS and non-HS broilers. Under high temperature (HT), a 1 (Control, HT-CON) + 2 (Zn source) × 2 (added Zn level) factorial arrangement of treatments was used. The 2 added Zn sources were Zn-Prot M and Zn sulfate (ZnS), and the 2 added Zn levels were 30 and 60 mg/kg. Under normal temperature (NT), a CON group (NT-CON) and pair-fed group (NT-PF) were included. The results showed that HS significantly reduced mRNA and protein expression levels of claudin-1, occludin, junctional adhesion molecule-A (JAMA), zonula occludens-1 (ZO-1) and zinc finger protein A20 (A20) in the jejunum, and HS also remarkably increased serum fluorescein isothiocyanate dextran (FITC-D), endotoxin and interleukin (IL)-1β contents, serum diamine oxidase (DAO) and matrix metalloproteinase (MMP)-2 activities, nuclear factor kappa-B (NF-κB) p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum. However, dietary supplementation with Zn, especially organic Zn as Zn-Prot M at 60 mg/kg, significantly decreased serum FITC-D, endotoxin and IL-1β contents, serum DAO and MMP-2 activities, NF-κB p65 mRNA expression level, and protein expression levels of NF-κB p65 and MMP-2 in the jejunum of HS broilers, and notably promoted mRNA and protein expression levels of claudin-1, ZO-1 and A20. Our results suggest that dietary Zn, especially 60 mg Zn/kg as Zn-Prot M, can alleviate HS-induced intestinal barrier function damage by promoting the expression of TJ proteins possibly via induction of A20-mediated suppression of the NF-κB p65/MMP-2 pathway in the jejunum of HS broilers.

中文翻译：

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具有中等螯合强度的日粮锌蛋白盐通过促进肉鸡空肠中 A20/NF-κB p65/MMP-2 通路紧密连接蛋白的表达，减轻热应激引起的肠道屏障功能损伤


本研究的目的是确定中等螯合强度的锌蛋白（Zn-Prot M）是否以及如何减轻热应激（HS）引起的肉鸡肠道屏障功能损伤。采用完全随机设计来比较测试蛋白质锌对 HS 和非 HS 肉鸡的影响。在高温（HT）下，使用1（对照，HT-CON）+2（锌源）×2（添加锌水平）处理的因子排列。 2种添加的Zn源为Zn-Prot M和硫酸锌(ZnS)，2种添加的Zn含量分别为30和60 mg/kg。常温（NT）下，包括CON组（NT-CON）和配对喂养组（NT-PF）。结果显示，HS显着降低了空肠中claudin-1、occludin、连接粘附分子-A (JAMA)、小带闭塞-1 (ZO-1) 和锌指蛋白 A20 (A20) 的 mRNA 和蛋白表达水平，并且HS还显着增加血清异硫氰酸葡聚糖荧光素（FITC-D）、内毒素和白细胞介素（IL）-1β含量、血清二胺氧化酶（DAO）和基质金属蛋白酶（MMP）-2活性、核因子κ-B（NF-κB）空肠中 p65 mRNA 表达水平以及 NF-κB p65 和 MMP-2 蛋白表达水平。然而，膳食补充锌，特别是60 mg/kg有机锌Zn-Prot M，显着降低血清FITC-D、内毒素和IL-1β含量、血清DAO和MMP-2活性、NF-κB p65 mRNA表达水平，以及HS肉鸡空肠中NF-κB p65和MMP-2的蛋白表达水平，并显着促进claudin-1、ZO-1和A20的mRNA和蛋白表达水平。 我们的结果表明，膳食锌，尤其是 60 mg Zn/kg 的 Zn-Prot M，可以通过促进 TJ 蛋白的表达来减轻 HS 诱导的肠道屏障功能损伤，这可能是通过诱导 A20 介导的 NF-κB p65/ 抑制来实现的。 HS 肉鸡空肠中的 MMP-2 通路。