Intestine derived lipopolysaccharide (LPS) is closely related to systemic inflammation and disorders, yet little is known about its roles in the weanling stress of piglets and its potential as a nutritional intervention target. This study aimed to investigate the potential of essential oils (EO) and organic acids (OA) in mitigating weaning stress in piglets by modulating the circulation of intestine derived LPS. Seventy-two weaned piglets at 21 d old with body weight of 8.12 ± 0.168 kg were randomly divided into a control group (CON) and an experimental group, each consisting of six pens with six piglets per pen, and were fed either a basal diet or a basal diet supplemented with 3 kg/t OA + 500 g/t EO (EO + OA). On the 14th day of the feeding trial, 12 weaned piglets were randomly selected from the CON group, and 6 piglets were selected from the experimental group. Based on diet composition and stress treatment, these 18 piglets were divided into the following three groups: 1) CON group. Piglets were fed a basal diet and received an intraperitoneal injection of saline as a control. 2) LPS group. Piglets were fed a basal diet and received an intraperitoneal injection of LPS (100 μg/kg body weight) to induce stress. 3) EO + OA + LPS group. Piglets were fed a basal diet supplemented with EO and OA and received an intraperitoneal injection of LPS (100 μg/kg body weight) to induce stress. The results showed that EO + OA significantly ameliorated the oxidative imbalance and inflammation disorder induced by LPS in piglets' serum and intestine by inhibiting the activation of the Toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB)/mitogen-activated protein kinase (MAPK) signaling pathway. Furthermore, compared to the LPS group, supplementation with EO + OA restored LPS-induced reductions in Bcl-2 protein expression in the piglets' intestines (P < 0.05) and mitigated morphological damage; it also enhanced both the protein expression and relative gene expression of the tight junction proteins occludin and claudin-1 (P < 0.05), and reduced the plasma diamine oxidase activity (DAO) and LPS content (P < 0.05). Compared to the CON group, supplementation with EO + OA altered the composition of the intestinal microbiota, increasing beneficial bacteria relative abundance (Faecalibacterium) (P < 0.05) and decreasing harmful bacteria relative abundance [Rikenellaceae_RC9_gut_group (P < 0.01), Negativibacillus (P < 0.05)]. Further analysis revealed that plasma LPS content in piglets was negatively correlated with the relative abundance of Faecalibacterium (r = −0.662, P = 0.021), Akkermansia (r = −0.492, P = 0.031), and average daily gain (ADG) (r = −0.912, P = 0.041). Plasma LPS content was also positively correlated with the plasma inflammatory factors interleukin (IL)-1β (r = 0.591, P = 0.021), IL-6 (r = 0.623, P = 0.021), IL-12 (r = 561, P = 0.031) contents, and the relative abundance of Negativibacillus (r = 0.712, P = 0.041). In summary, the addition of EO + OA prevents the leakage of intestine derived LPS into the circulation by improving intestinal integrity and microbiota composition, thereby enhancing antioxidant and anti-inflammatory abilities and growth performance of weaned piglets.

中文翻译：

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植物精油与有机酸结合通过肠道微生物调节修复脂多糖诱导的断奶仔猪肠漏


肠源脂多糖 （LPS） 与全身炎症和疾病密切相关，但对其在仔猪断奶应激中的作用及其作为营养干预靶点的潜力知之甚少。本研究旨在探讨精油 （EO） 和有机酸 （OA） 通过调节肠道来源的 LPS 的循环来减轻仔猪断奶应激的潜力。将 72 头 21 d 龄、体重为 8.12 ± 0.168 kg 的断奶仔猪随机分为对照组 （CON） 和实验组，每个组由 6 个猪栏组成，每个猪栏 6 头仔猪，饲喂基础日粮或基础日粮，添加 3 kg/t OA + 500 g/t EO （EO + OA）。饲喂试验第 14 天，从 CON 组中随机选择 12 头断奶仔猪，从实验组中选择 6 头仔猪。根据日粮成分和应激处理，将这 18 头仔猪分为以下 3 组： 1） CON 组。仔猪饲喂基础日粮，并接受腹膜内注射生理盐水作为对照。2） LPS 组。仔猪饲喂基础日粮，腹膜内注射 LPS （100 μg/kg 体重） 以诱导应激。3） EO + OA + LPS 组。仔猪饲喂补充 EO 和 OA 的基础日粮，腹腔注射 LPS （100 μg/kg 体重） 以诱导应激。结果表明，EO + OA 通过抑制 Toll 样受体 4 （TLR4）/核因子-κB （NF-κB）/丝裂原活化蛋白激酶 （MAPK） 信号通路的激活，显著改善 LPS 诱导的仔猪血清和肠道氧化失衡和炎症紊乱。 此外，与 LPS 组相比，补充 EO + OA 恢复了 LPS 诱导的仔猪肠道中 Bcl-2 蛋白表达的降低 （P < 0.05） 并减轻了形态损伤;还增强了紧密连接蛋白 occludin 和 claudin-1 的蛋白表达和相对基因表达 （P < 0.05），降低了血浆二胺氧化酶活性 （DAO） 和 LPS 含量 （P < 0.05）。与CON组相比，补充EO + OA改变了肠道微生物群的组成，增加了有益菌的相对丰度（粪杆菌）（P < 0.05）和降低了有害菌的相对丰度[Rikenellaceae_RC9_gut_group（P < 0.01），阴性杆菌（P < 0.05）]。进一步分析显示，仔猪血浆 LPS 含量与粪杆菌属 （r = −0.662，P = 0.021）、阿克曼菌属 （r = −0.492，P = 0.031） 和平均日增重 （ADG） 的相对丰度呈负相关 （r = −0.912，P = 0.041）。血浆 LPS 含量也与血浆炎症因子白细胞介素 （IL）-1β （r = 0.591，P = 0.021）、IL-6 （r = 0.623，P = 0.021）、IL-12 （r = 561，P = 0.031） 含量和负性芽孢杆菌的相对丰度呈正相关 （r = 0.712，P = 0.041）。综上所述，添加 EO + OA 通过改善肠道完整性和微生物群组成来防止肠道衍生的 LPS 泄漏到循环中，从而提高断奶仔猪的抗氧化和抗炎能力以及生长性能。