Institute of Animal Nutrition, Feed Engineering Research Centre of Sichuan Province, Sichuan Agricultural University, Chengdu 611130, China.
Sichuan Industrial Institute of Antibiotics, School of Pharmacy, Chengdu University, Chengdu 610106, China.
J Anim Sci. 2021 Nov 1;99(11). doi: 10.1093/jas/skab313.
To explore whether Radix Bupleuri extract (RBE) could protect lung injury of broilers under ammonia (NH3) exposure, 360 one-d-old male broilers were randomly allocated to four groups of six replicates each in a 2 × 2 factorial design with two diets (the basal diet [control; CON] and the basal diet supplemented with RBE [RB]) and two air conditions (normal condition [<2 ppm of NH3; NOR] and NH3 exposure [70 ppm of NH3; NH70]). The RB diet contained 80 mg saikosaponins/kg diet. On day 7, the lung tissues were collected and the lung epithelial cells (LEC) were isolated. Our experimental results showed that the NH3 exposure decreased body weight gain and feed intake irrespective of dietary treatments during days 1 to 7. However, the RBE addition decreased feed consumption to body weight gain ratio in broilers under NH70 conditions. In the LEC of CON-fed broilers under NH70 conditions, Golgi stacks showed the dilation of cisternaes and reduced secretory vesicles, mitochondria enlarged, the inner membrane of mitochondria became obscure, and the cristae of mitochondria ruptured, whereas only a mild enlargement of Golgi cisternaes and the part rupture of mitochondrial cristaes occurred in the LEC of RB-fed broilers under NH70 conditions. The NH3 exposure increased malondialdehyde (MDA) level, but decreased total antioxidant capacity (T-AOC) in the lungs of CON-fed broilers. However, the RBE addition decreased MDA level and increased T-AOC in the lungs of broilers under NH70 conditions. Simultaneously, the NH3 exposure increased apoptotic rate (AR), mitochondrial membrane potential (MMP), and reactive oxygen species (ROS) level in the isolated LEC of CON-fed broilers. The RBE addition decreased AR, MMP, and ROS in the isolated LEC of broilers under NH70 condition. Besides, the NH3 exposure increased mRNA expression of B-cell lymphoma-2 associated X protein (BAX), caspase-3, and tumor necrosis factor α (TNF-α), but increased interferon γ (IFN-γ) mRNA abundance in the lungs of CON-fed broilers. The RBE supplement decreased mRNA levels of BAX, caspase-3, and TNF-α, but increased IFN-γ, interleukin (IL)-4, and IL-17 mRNA levels in the lungs of broilers under NH70 conditions. These results indicated that dietary RBE addition alleviated NH3 exposure-induced intercellular ultrastructural damage via mitochondrial apoptotic pathway, possibly due to RBE-induced increase of antioxidant capacity and immunomodulatory function in the lungs of broilers under NH3 exposure.
为了探究柴胡提取物（RBE）是否可以保护氨气（NH3）暴露下肉鸡的肺损伤，将 360 只 1 日龄雄性肉鸡随机分配到 4 个组，每个组 6 个重复，采用 2×2 析因设计，分为 2 种日粮（基础日粮[对照；CON]和基础日粮添加 RBE[RB]）和 2 种空气条件（正常条件[<2 ppm NH3；NOR]和 NH3 暴露[70 ppm NH3；NH70]）。RB 日粮含有 80 mg 柴胡皂苷/kg 日粮。在第 7 天，收集肺组织并分离肺上皮细胞（LEC）。我们的实验结果表明，无论日粮处理如何，NH3 暴露都会在第 1 天至第 7 天降低肉鸡的体重增加和采食量。然而，在 NH70 条件下，RBE 的添加降低了肉鸡的采食量与体重增加的比值。在 CON 喂养的 NH70 条件下 LEC 的 Golgi 堆栈中，cisternaes 扩张，分泌小泡减少，线粒体增大，线粒体内膜模糊，线粒体嵴破裂，而在 RB 喂养的 NH70 条件下 LEC 中仅发生 Golgi cisternaes 的轻度扩张和部分线粒体嵴破裂。NH3 暴露增加了 CON 喂养肉鸡肺中的丙二醛（MDA）水平，但降低了总抗氧化能力（T-AOC）。然而，RBE 的添加降低了 NH70 条件下肉鸡肺中的 MDA 水平并增加了 T-AOC。同时，NH3 暴露增加了 CON 喂养肉鸡分离的 LEC 的凋亡率（AR）、线粒体膜电位（MMP）和活性氧（ROS）水平。RBE 的添加降低了 NH70 条件下肉鸡分离的 LEC 的 AR、MMP 和 ROS。此外，NH3 暴露增加了 CON 喂养肉鸡肺中的 B 细胞淋巴瘤-2 相关 X 蛋白（BAX）、半胱天冬酶-3 和肿瘤坏死因子 α（TNF-α）的 mRNA 表达，但增加了干扰素 γ（IFN-γ）mRNA 的丰度。RBE 补充降低了 NH70 条件下肉鸡肺中 BAX、半胱天冬酶-3 和 TNF-α的 mRNA 水平，但增加了 IFN-γ、白细胞介素（IL）-4 和 IL-17 的 mRNA 水平。这些结果表明，日粮中 RBE 的添加通过线粒体凋亡途径缓解了 NH3 暴露引起的细胞内超微结构损伤，这可能是由于 RBE 诱导 NH3 暴露肉鸡的肺中抗氧化能力和免疫调节功能增强所致。
