The heavy metal poisoning in humans and fish represents a significant global problem. Copper (Cu), as an essential micronutrient in human and animal metabolism, often accumulates excessively in aquatic environment. The microbial floc is rich in a variety of probiotics and bioactive compounds, which has been documented to have the functions of antioxidant and immunoenhancement. A 64-day experiment was conducted to investigate the protective effects and potential mechanisms of dietary supplementation of microbial floc and Cu exposure on inflammatory response, oxidative stress, intestinal apoptosis and barrier dysfunction in Rhynchocypris lagowski Dybowski. A total of four hundred fifty R. lagowski were fed five experimental diets containing graded levels of microbial floc from 0% to 16% (referred to as B0, B4, B8, B12 and B16, respectively) in the first 60 days, and 96 h of acute copper exposure test was carried out in the last four days. The results showed that microbial floc exerted significant alleviative effects by preventing alterations in the levels of bioaccumulation, caspase3, caspase8, caspase9, malondialdehyde and interleukin-6, improving the activities of lysozyme, complement C3, complement C4, immunoglobulin M, alkaline phosphatase, heat shock protein 70, heat shock protein 90 and glutathione peroxidase, catalase, superoxide dismutase, total antioxidant capacity. In addition, microbial floc assisted in regulating the expression of NF-κB/Nrf2 signaling molecule genes, including NF-κB, TNF-α, IL-1β, IL-8, IL-10, TGF-β, Keap1, Nrf2, Maf, HO-1, CAT, CuZn-SOD, GCLC and GPX. Overall, our results suggest that dietary supplementation with of microbial floc can alleviate copper-induced inflammation, oxidative stress, intestinal apoptosis and barrier dysfunction in R. lagowski. A suitable supplementation level of approximately 12% microbial floc is recommended in the present study.

人类和鱼类中的重金属中毒代表了一个重大的全球性问题。铜（Cu）作为人类和动物新陈代谢中必不可少的微量营养素，经常在水生环境中积累过多。微生物絮凝物富含各种益生菌和生物活性化合物，据报道它们具有抗氧化和增强免疫功能。进行了为期64天的实验，研究了膳食中添加微生物絮凝物和铜暴露对Rhynchocypris lagowski Dybowski的炎症反应，氧化应激，肠道细胞凋亡和屏障功能障碍的保护作用及其潜在机制。共有450个R. lagowski在最初的60天中，分别喂食了5种含微生物絮凝物分级水平从0％至16％的实验饮食（分别称为B0，B4，B8，B12和B16），并进行了96小时的急性铜暴露测试在过去四天内。结果表明，微生物絮凝物通过防止生物蓄积水平，caspase3，caspase8，caspase9，丙二醛和白介素-6的水平改变，改善了溶菌酶，补体C3，补体C4，免疫球蛋白M，碱性磷酸酶，热量的活性，发挥了显着的缓解作用。休克蛋白70，热休克蛋白90和谷胱甘肽过氧化物酶，过氧化氢酶，超氧化物歧化酶，总抗氧化能力。此外，微生物絮凝物还有助于调节NF-κB/ Nrf2信号分子基因的表达，包括NF-κB，TNF-α，IL-1β，IL-8，IL-10，TGF-β，Keap1，Nrf2，Maf，HO-1，CAT，CuZn-SOD，GCLC和GPX。总体而言，我们的结果表明，膳食中补充微生物絮凝物可以缓解拉格夫斯基铜引起的炎症，氧化应激，肠道细胞凋亡和屏障功能障碍。在本研究中建议大约12％的微生物絮凝物的适当补充水平。