Abstract：
In recent years, the concentrations of cadmium (Cd) and diclofenac (DCF) in water have frequently exceeded the standard; however, the toxic effects of these two pollutants on grass carp under single and combined exposure are unknown. In this study, the concentrations of pollutants in different tissues were detected, and the toxicities of the two pollutants to grass carp under different exposure conditions were compared based on growth traits, biochemical responses, gut microbiome, and transcriptomes. Based on these findings, the brain showed the lowest levels of Cd and DCF accumulation. Oxidative stress and pathological damage were observed in the brain and intestines. Changes in the structure and abundance of the gut microflora affect the synthesis of neurotransmitters, such as GABA and steroids. Differentially expressed genes in the brain were enriched in circadian rhythm functions. The expression of PER, CLOCK,1L-1β, 1L-17, and other genes are related to the abundance of Akkermansia, which indicates that the disorder of gut microflora will affect the normal circadian rhythm of the brain. All indices in the recovery group showed an increasing trend. Overall, the toxicity of Cd and DCF showed antagonism, and a single exposure had a stronger effect on gut microorganisms and circadian rhythm, which provided a scientific basis for exploring the comprehensive effects of different pollutants.
摘要：
近年来,水中镉（Cd）和双氯芬酸（DCF）的浓度经常超标；但是，这两种污染物在单一和联合暴露下对草鱼的毒性作用尚不清楚。在这项研究中,检测了不同组织中污染物的浓度，并根据生长性状比较了两种污染物在不同暴露条件下对草鱼的毒性，生化反应，肠道微生物组，和转录组。基于这些发现,大脑显示出最低的Cd和DCF积累水平。在脑和肠中观察到氧化应激和病理损伤。肠道菌群结构和丰度的变化影响神经递质的合成，如GABA和类固醇。大脑中差异表达的基因富含昼夜节律功能。PER的表达，时钟,1L-1β，1L-17，其他基因与Akkermansia的丰度有关，这表明肠道菌群的紊乱会影响大脑的正常昼夜节律。恢复组的所有指标均呈增加趋势。总的来说,Cd和DCF的毒性表现出拮抗作用，一次暴露对肠道微生物和昼夜节律有更强的影响，为探索不同污染物的综合效应提供了科学依据。
