Metamifop (MET) is an effective herbicide that has been extensively used in paddy fields. Previous research demonstrated that MET was highly toxic to zebrafish embryos, and this threat has caused great concern; moreover, 0.40 mg/L MET elevated the hepatosomatic index (HSI) in adult zebrafish without lethal effect after 21 d of exposure. In this study, we further determined the detailed impacts of MET on adult zebrafish at sublethal concentrations (0.025, 0.10 and 0.40 mg/L). We found that 0.40 mg/L MET caused liver injury by increasing the activity of aspartate aminotransferase and alanine aminotransferase in plasma, the content of interleukin-1β, IL-6, tumor necrosis factor-α, and mRNA expression level of genes associated with inflammatory response in liver of adult zebrafish. The hepatic triglyceride (TG), free fatty acid and fatty acid synthase levels were significantly elevated in 0.40 mg/L MET-treated group (1.55-, 2.20- and 2.30-fold, respectively), and the transcript of lipid accumulation-related genes (fabp10, fas, acc, chrebp, dagt2 and agpat4) were upregulated. Meanwhile, the total cholesterol content was decreased by 0.48-fold, bile acid level was increased by 2.44-fold, and levels of cholesterol metabolism-related genes (apoa-1a, hmgcra, cyp51, dhcr7 and cyp7a1) were increased, suggesting cholesterol metabolism disorder occurred in zebrafish. Furthermore, analysis of lipidomics revealed that 0.40 mg/L MET significantly increased the abundance of 91 lipids, which mainly belonged to TG lipid class and were enriched in pathways of glycerolipid metabolism, cholesterol metabolism, etc. These results suggested that MET exposure at sublethal concentrations would induce hepatic inflammation and lipid metabolism disorders in adult zebrafish.

恶唑酰草胺（MET）是一种有效的除草剂，已广泛用于稻田。此前的研究表明，MET对斑马鱼胚胎具有剧毒，这种威胁引起了人们的高度关注；此外，0.40 mg/L MET 会升高成年斑马鱼的肝体指数 (HSI)，在暴露 21 天后没有致死作用。在本研究中，我们进一步确定了亚致死浓度（0.025、0.10 和 0.40 mg/L）下 MET 对成年斑马鱼的详细影响。我们发现0.40 mg/L MET通过增加血浆中天冬氨酸转氨酶和丙氨酸转氨酶的活性、白细胞介素1β、IL-6、肿瘤坏死因子-α的含量以及炎症相关基因的mRNA表达水平而引起肝损伤。成年斑马鱼肝脏的反应。 0.40 mg/L MET处理组的肝甘油三酯（TG）、游离脂肪酸和脂肪酸合酶水平显着升高（分别为1.55倍、2.20倍和2.30倍），并且脂质积累相关基因的转录本（ fabp10、fas、acc、chrebp、dagt2和agpat4 ）上调。同时，总胆固醇含量降低0.48倍，胆汁酸水平升高2.44倍，胆固醇代谢相关基因（ apoa-1a、hmgcra、cyp51、dhcr7和cyp7a1 ）水平升高，提示胆固醇代谢异常。斑马鱼身上出现了紊乱。此外，脂质组学分析显示，0.40 mg/L MET显着增加了91种脂质的丰度，这些脂质主要属于TG脂质类，富集在甘油脂代谢、胆固醇代谢等途径中。 这些结果表明，亚致死浓度的 MET 暴露会诱发成年斑马鱼的肝脏炎症和脂质代谢紊乱。