Necrotic enteritis (NE) is an economically important disease of broiler chickens caused by Clostridium perfringens (CP). The pathogenesis, or disease process, of NE is still not clear. This study aimed to identify the alterations of metabolites and metabolic pathways associated with subclinical or clinical NE in CP infected birds and to investigate the possible variations in the metabolic profile of birds infected with different isolates of CP. Using a well-established NE model, the protein content of feed was changed abruptly before exposing birds to CP isolates with different toxin genes combinations (cpa, cpb2, netB, tpeL; cpa, cpb2, netB; or cpa, cpb2). Metabolomics analysis of jejunal contents was performed by a targeted, fully quantitative LC-MS/MS based assay. This study detected statistically significant differential expression of 34 metabolites including organic acids, amino acids, fatty acids, and biogenic amines, including elevation of butyric acid at onset of NE in broiler chickens. Subsequent analysis of broilers infected with CP isolates with different toxin gene combinations confirmed an elevation of butyric acid consistently among 21 differentially expressed metabolites including organic acids, amino acids, and biogenic amines, underscoring its potential role during the development of NE. Furthermore, protein-metabolite network analysis revealed significant alterations in butyric acid and arginine-proline metabolisms. This study indicates a significant metabolic difference between CP-infected and non-infected broiler chickens. Among all the metabolites, butyric acid increased significantly in CP-infected birds compared to non-infected healthy broilers. Logistic regression analysis revealed a positive association between butyric acid (coefficient: 1.23, P < 0.01) and CP infection, while showing a negative association with amino acid metabolism. These findings suggest that butyric acid could be a crucial metabolite linked to the occurrence of NE in broiler chickens and may serve as an early indicator of the disease at the farm level. Further metabolomic experiments using different NE animal models and field studies are needed to determine the specificity and to validate metabolites associated with NE, regardless of predisposing factors.

中文翻译：

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肉鸡动物模型空肠中丁酸水平升高：从产气荚膜梭菌感染的早期发作到坏死性肠炎的临床疾病


坏死性肠炎 （NE） 是由产气荚膜梭菌 （CP） 引起的肉鸡经济上重要的疾病。NE 的发病机制或疾病过程仍不清楚。本研究旨在确定 CP 感染家禽中与亚临床或临床 NE 相关的代谢产物和代谢途径的改变，并研究感染不同 CP 分离株的家禽代谢特征的可能变化。使用成熟的 NE 模型，在将家禽暴露于具有不同毒素基因组合的 CP 分离株之前，饲料的蛋白质含量突然改变 （cpa， cpb2， netB， tpeL;cpa、cpb2、netB;或 CPA、CPB2）。空肠内容物的代谢组学分析通过靶向、全定量 LC-MS/MS 分析进行。本研究检测到 34 种代谢物的差异表达，包括有机酸、氨基酸、脂肪酸和生物胺，包括肉鸡 NE 开始时丁酸升高，具有统计学意义。随后对感染具有不同毒素基因组合的 CP 分离株的肉鸡进行分析，证实 21 种差异表达代谢物（包括有机酸、氨基酸和生物胺）的丁酸持续升高，强调了其在 NE 发展过程中的潜在作用。此外，蛋白质-代谢物网络分析显示丁酸和精氨酸-脯氨酸代谢发生显著改变。这项研究表明，CP 感染和未感染的肉鸡之间存在显着的代谢差异。在所有代谢物中，与未感染的健康肉鸡相比，CP 感染的鸡的丁酸显著增加。Logistic 回归分析显示丁酸 （系数： 1.23，P < 0.01） 和 CP 感染，同时显示与氨基酸代谢呈负相关。这些发现表明，丁酸可能是与肉鸡 NE 发生有关的关键代谢物，并可能作为农场层面疾病的早期指标。需要使用不同的 NE 动物模型和现场研究进行进一步的代谢组学实验，以确定特异性并验证与 NE 相关的代谢物，而不管易感因素如何。