We characterized the mechanism underlying star anise (Illicium verum Hook.f) oil (SAO)-mediated antioxidant status during subclinical Escherichia coli (E. coli) challenge. A total of 512 male birds (White Leghorn) at 30 wk of age with similar body weight (2.14 ± 0.02 kg) were randomly divided into 2 groups with 1 group being orally challenged with E. coli (every other day from day 15 to day 27) during the experiment. Each group of birds was then randomly allocated to dietary treatment of SAO supplementation at 0, 200, 400, or 600 mg/kg of basal diet (8 replicate cages during each treatment). The treatments were arranged a 4 × 2 factorial arrangement. The experiment comprised 1 wk of adaptation and 3 wks of data collection. There was no interaction (P > 0.05) between SAO supplementation and E. coli challenge for final body weight and average daily feed intake of birds. However, E. coli challenge resulted in a significant decrease (P < 0.001) in final body weight of birds as compared with unchallenged birds. There were interactions between SAO supplementation and E. coli challenge for the activity of glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) concentration in serum and for the activity of GSH-Px in the liver of birds. Supplementation of SAO enhanced the activities of antioxidant enzymes but decreased the MDA content in the serum and liver of birds, and it also enhanced the expression of genes including superoxide dismutase, catalase, and nuclear factor E2-related factor 2 (Nrf2) in the liver of the birds. Meanwhile, supplementation of SAO can also reduce E. coli challenge-induced oxidative stress in the serum and liver of birds, and the efficacy of SAO in birds during subclinical E. coli challenge is dose-dependent. In conclusion, the enhancement of antioxidant capacity by star anise or its effective compounds is through upregulation of Nrf2 signaling pathway. The optimum supplementation dose of SAO for protecting birds against E. coli challenge is 400 mg/kg.

中文翻译：

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八角茴香（Illicium v​​erum Hook.f）油对亚临床大肠杆菌攻击过程中鸡核因子E2相关因子2信号通路的影响。

我们表征了亚临床大肠杆菌（E. coli）攻击过程中八角茴香（Illicium v​​erum Hook.f）油（SAO）介导的抗氧化剂状态的机制。将30周龄，体重相似（2.14±0.02 kg）的512只雄性禽（White Leghorn）随机分为2组，每组从第15天到第25天每天口服大肠杆菌攻击。 27）在实验期间。然后将每组家禽随机分配到以0、200、400或600 mg / kg基础饮食（每个处理过程中有8个重复笼子）的SAO饮食进行饮食处理。处理安排为4×2阶乘安排。实验包括1周的适应和3周的数据收集。SAO补充剂和E之间没有相互作用（P> 0.05）。大肠菌对最终体重和家禽平均日采食量的挑战。但是，与未挑战的鸟类相比，大肠杆菌的挑战导致鸟类的最终体重显着降低（P <0.001）。SAO补充剂和大肠杆菌挑战之间存在相互作用，这些相互作用包括血清中谷胱甘肽过氧化物酶（GSH-Px）和丙二醛（MDA）浓度的活性以及鸟类肝脏中GSH-Px的活性。补充SAO增强了家禽的抗氧化酶活性，但降低了血清和肝脏中MDA的含量，还增强了肝脏中超氧化物歧化酶，过氧化氢酶和核因子E2相关因子2（Nrf2）的基因表达。的鸟。同时，补充SAO也可以降低E。大肠杆菌挑战引起的鸟类血清和肝脏中的氧化应激，以及亚临床大肠杆菌挑战期间鸟类中SAO的功效是剂量依赖性的。总之，八角茴香或其有效化合物的抗氧化能力增强是通过上调Nrf2信号通路来实现的。用于保护禽类免受大肠杆菌攻击的SAO最佳补充剂量为400 mg / kg。