探讨柴胡提取物(RBE)对氨(NH3)暴露对肉鸡肺损伤的保护作用。将360只1日龄雄性肉鸡随机分为4组,每组6个重复,采用2×2因子设计,采用两种日粮(基础日粮[对照;CON]和补充RBE[RB]的基础日粮)和两种空气条件(正常条件[<2ppm的NH3;NOR]和NH3暴露[70ppm的NH3;NH70])。RB饮食包含80mg柴胡皂苷/kg饮食。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,与第1至7天的饮食处理无关,NH3暴露会降低体重增加和采食量。然而,在NH70条件下,RBE的添加降低了肉鸡的饲料消耗与体重增加比。在NH70条件下CON饲喂肉鸡的LEC中,高尔基堆栈显示出水箱扩张和分泌囊泡减少,线粒体扩大,线粒体的内膜变得模糊,线粒体的鳞破裂了,而在NH70条件下,饲喂RB的肉鸡的LEC中仅发生高尔基蓄水池的轻度扩大和线粒体cr的部分破裂。NH3暴露增加丙二醛(MDA)水平,但降低了CON饲喂肉鸡肺部的总抗氧化能力(T-AOC)。然而,在NH70条件下,RBE的添加降低了肉鸡肺部的MDA水平并增加了T-AOC。同时,NH3暴露增加细胞凋亡率(AR),线粒体膜电位(MMP),饲喂CON的肉鸡的分离LEC中的活性氧(ROS)水平。RBE的添加降低了AR,MMP,NH70条件下分离的肉鸡LEC中的ROS。此外,NH3暴露增加B细胞淋巴瘤-2相关X蛋白(BAX)的mRNA表达,caspase-3和肿瘤坏死因子α(TNF-α),但增加了CON饲喂肉鸡肺中干扰素γ(IFN-γ)mRNA的丰度。RBE补充剂降低了BAX的mRNA水平,caspase-3和TNF-α,但IFN-γ增加,NH70条件下肉鸡肺中白细胞介素(IL)-4和IL-17mRNA水平。这些结果表明,饮食中添加RBE可以通过线粒体凋亡途径减轻NH3暴露引起的细胞间超微结构损伤,可能是由于在NH3暴露下RBE诱导的肉鸡肺部抗氧化能力和免疫调节功能的增加。
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.