Currently, the effect of selenium and oxidized fish oil interactions on the intestinal lipid metabolism and antioxidant responses of fish remains unknown. Herein, yellow catfish Pelteobagrus fulvidraco (weight: 3.99 ± 0.01 g) were used as experimental animals and were fed four diets: an adequate amount of selenium (0.25 mg kg⁻¹) with fresh fish oil (A-Se+FFO), an adequate amount of selenium with oxidized fish oil (A-Se+OFO), a high amount of selenium (0.50 mg kg⁻¹) with fresh fish oil (H-Se+FFO), and a high amount of selenium with oxidized fish oil (H-Se+OFO). The feeding experiment was conducted for 10 weeks. The results showed that selenium supplementation alleviated the intestinal tissue damage and reduced the lipid accumulation that was induced by oxidized fish oils. Meanwhile, we also found that 0.50 mg kg⁻¹ selenium reduced the oxidative stress that is caused by oxidized fish oils through increasing the GSH and the activity and mRNA expression of antioxidant enzymes. Dietary selenium and oxidized fish oils also affected the mRNA expression of intestinal selenoproteins including selenow2a, selenop2, and selenot2. Mechanistically, Se and oxidized eicosapentaenoic acid (oxEPA) influenced the GSH content by affecting the DNA binding ability of activating transcription factor (ATF) 3 to the slc7a11 promoter. For the first time, our results suggested that selenium alleviated the oxidized fish oil-induced intestinal lipid deposition and the oxidative stress of the fish. We also elucidated the novel mechanism of selenium increasing the GSH content by affecting the interaction of ATF3 and the slc7a11 promoter.

中文翻译：

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膳食硒和氧化鱼油对黄颡鱼肠道脂质代谢和抗氧化反应的影响

目前，硒和氧化鱼油相互作用对鱼类肠道脂质代谢和抗氧化反应的影响尚不清楚。在此，以黄鲶（体重：3.99 ± 0.01 g）为实验动物，喂食四种饲料：足量的硒（0.25 mg kg ^-1）和新鲜鱼油（A-Se+FFO）、足量硒和氧化鱼油 (A-Se+OFO)，大量硒 (0.50 mg kg ^-1) 与新鲜鱼油 (H-Se+FFO) 和大量硒与氧化鱼油 (H-Se+OFO)。喂养实验进行了10周。结果表明，补充硒可减轻肠道组织损伤并减少氧化鱼油引起的脂质积累。同时，我们还发现0.50 mg kg ^-1硒通过增加GSH和抗氧化酶的活性和mRNA表达来降低由氧化鱼油引起的氧化应激。膳食硒和氧化鱼油也影响肠道硒蛋白的mRNA表达，包括selenow2a、selenop2和selenot2。. 机制上，硒和氧化的二十碳五烯酸 (oxEPA) 通过影响激活转录因子 (ATF) 3 与slc7a11启动子的 DNA 结合能力来影响 GSH 含量。我们的研究结果首次表明，硒可以缓解氧化鱼油引起的肠道脂质沉积和鱼的氧化应激。我们还阐明了硒通过影响 ATF3 和slc7a11启动子的相互作用来增加 GSH 含量的新机制。