Long-term high-fat diets (HF) lead to lipid accumulation and an oxidative stress response, which deteriorates the chemical and physical characteristics of fish muscle. Green tea extracts, such as (−)-epigallocatechin-3-O-gallate (EGCG) and (−)-epicatechin (EC), have been found to regulate antioxidant ability and lipid metabolism. However, the effects of EGCG and EC on alleviating oxidative stress and lipid metabolism disorders caused by HF are unclear. Furthermore, the underlying mechanisms remain unknown. In this study, a total of 360 carp (average weight: 9.75 ± 0.09 g) were provided with four experimental diets: a control diet (CN, 6.15% dietary lipids), a high-fat diet (HF, 14.05% dietary lipids), HF supplemented with EGCG (HF + EGCG, 14.05% dietary lipids +50 mg/kg EGCG), and a HF diet supplemented with EC (HF + EC, 14.05% dietary lipids +1000 mg/kg EC) for a duration of 84 days. The results indicated that EGCG or EC ameliorated the negative effects of the HF diet on muscle tissue. Apart from muscle physical characteristics, EGCG decreased yellowness (*), redness (*), and dripping loss ( < 0.05). Apart from muscle nutritional composition and antioxidant status, EC mitigated the reduction in protein levels in the muscle induced by the HF diet. Similarly, EGCG and EC mitigated the excessive accumulation of lipids and reactive oxygen species (ROS) in the muscle induced by the HF diet ( < 0.05). Further study showed that EGCG or EC facilitated the phosphorylation of AMP-activated protein kinase (AMPK) and increased silent information regulator 1 (Sirt1) and PPARγ coactivator-1 alpha (PGC-1α) expression in muscle. Taken together, the results of this study revealed that EGCG or EC enhance lipid metabolism and antioxidant capacity in the muscle of common carp ( L.) via the AMPK/Sirt1/PGC-1α pathway.

中文翻译：

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(−)-表没食子儿茶素-3-O-没食子酸酯或 (−)-表儿茶素增强高脂饮食鲤鱼 (Cyprinus carpio L.) 的脂质分解代谢和抗氧化防御：来自 AMPK/Sirt1/PGC-1α 的机制见解信号通路

长期高脂肪饮食（HF）会导致脂质积累和氧化应激反应，从而恶化鱼肌肉的化学和物理特性。绿茶提取物，如 (−)-表没食子儿茶素-3-O-没食子酸酯 (EGCG) 和 (−)-表儿茶素 (EC)，被发现可以调节抗氧化能力和脂质代谢。然而，EGCG和EC对缓解心力衰竭引起的氧化应激和脂质代谢紊乱的作用尚不清楚。此外，潜在的机制仍然未知。在本研究中，共有 360 条鲤鱼（平均体重：9.75 ± 0.09 g）提供四种实验饲料：对照饲料（CN，6.15% 膳食脂质）、高脂饲料（HF，14.05% 膳食脂质） ，HF 补充 EGCG（HF + EGCG，14.05% 膳食脂质 +50 mg/kg EGCG），以及 HF 饮食补充 EC（HF + EC，14.05% 膳食脂质 +1000 mg/kg EC），持续时间 84天。结果表明，EGCG 或 EC 改善了 HF 饮食对肌肉组织的负面影响。除了肌肉物理特性外，EGCG 还降低了黄度 (*)、红度 (*) 和滴水损失 (< 0.05)。除了肌肉营养成分和抗氧化状态外，EC 还可以减轻 HF 饮食引起的肌肉蛋白质水平下降。同样，EGCG 和 EC 减轻了 HF 饮食引起的肌肉中脂质和活性氧 (ROS) 的过度积累 (<0.05)。进一步的研究表明，EGCG 或 EC 促进 AMP 激活蛋白激酶 (AMPK) 的磷酸化，并增加肌肉中沉默信息调节因子 1 (Sirt1) 和 PPARγ 辅激活因子 1 α (PGC-1α) 的表达。综上所述，本研究结果表明，EGCG 或 EC 通过 AMPK/Sirt1/PGC-1α 途径增强鲤鱼 (L.) 肌肉的脂质代谢和抗氧化能力。