Wang Yachao, Jiang Li, Li Yuanfeng, Luo Xuegang, He Jian
School of Life Science and Engineering, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China.
Engineering Research Center of Biomass Materials, Ministry of Education, Southwest University of Science and Technology, Mianyang, Sichuan, 621010, China.
Biol Trace Elem Res. 2016 Aug;172(2):488-495. doi: 10.1007/s12011-015-0598-7. Epub 2016 Jan 6.
This study assessed the effects of different selenium (Se) supplementation levels on oxidative stress, cytokines, and immunotoxicity in chicken thymus. A total of 180 laying hens (1 day old; Mianyang, China) were randomly divided into 4 groups (n = 45). The chickens were maintained either on a basic diet (control group) containing 0.2 mg/kg Se, a low-supplemented diet containing 5 mg/kg Se, a medium-supplemented diet containing 10 mg/kg Se, or a high-supplemented diet containing 15 mg/kg Se for 15, 30, and 45 days, respectively. Over the entire experimental period, serum and thymus samples were collected and used for the detection of the experimental index. The results indicated that the antioxidative enzyme activities and messenger RNA (mRNA) levels of antioxidative enzymes, IFN-γ and IL-2 in the thymus, and the content of IFN-γ and IL-2 in the serum of excessive-Se-treated chickens at all time points (except for the 5 mg/kg Se supplement group at 15 days) were significantly decreased (P < 0.05) compared to the corresponding control groups. Interestingly, a significantly increase (P < 0.05) in the content of IFN-γ was observed in the serum and thymus in the 5 mg/kg Se supplement group at 15 and 30 days compared to the corresponding control groups. In histopathological examination, the thymus tissue from excessive-Se-treated chickens revealed different degrees of cortex drop, incrassation of the medulla, and degeneration of the reticular cells. These results suggested that the excessive Se could result in a decrease in immunity, an increase in oxidative damage, and a series of clinical pathology changes, such as cortex drop, incrassation of the medulla, and degeneration of the reticular cells.
本研究评估了不同硒（Se）添加水平对鸡胸腺氧化应激、细胞因子和免疫毒性的影响。选取180只1日龄蛋鸡（来自中国绵阳），随机分为4组（每组n = 45）。分别用含0.2 mg/kg硒的基础日粮（对照组）、含5 mg/kg硒的低添加日粮、含10 mg/kg硒的中添加日粮或含15 mg/kg硒的高添加日粮饲养这些鸡，饲养时间分别为15天、30天和45天。在整个实验期间，采集血清和胸腺样本用于检测实验指标。结果表明，在所有时间点（除15天时的5 mg/kg硒添加组外），高硒处理组鸡的胸腺中抗氧化酶活性、抗氧化酶信使核糖核酸（mRNA）水平、干扰素-γ（IFN-γ）和白细胞介素-2（IL-2），以及血清中IFN-γ和IL-2的含量，与相应对照组相比均显著降低（P < 0.05）。有趣的是，与相应对照组相比，在15天和30天时，5 mg/kg硒添加组鸡的血清和胸腺中IFN-γ含量显著增加（P < 0.05）。组织病理学检查显示，高硒处理组鸡的胸腺组织出现不同程度的皮质变薄、髓质增厚和网状细胞变性。这些结果表明，过量的硒会导致免疫力下降、氧化损伤增加以及一系列临床病理变化，如皮质变薄、髓质增厚和网状细胞变性。
