At present, large yellow croaker, Larimichthys crocea, a carnivorous fish ranked fifth in aquaculture production among marine finfishes in the world, still relies on raw fish diet because formulated feed alone is not able to sustain rapid growth of the fish. The present study evaluated growth, feed utilization efficiency, body composition and antioxidant capacity of large yellow croaker fed diets containing four protein (430, 460, 490 and 520 g/kg) and three lipid (60, 90 and 120 g/kg) levels. Fish weighing 11.4 ± 2.8 g were fed with the test diets in net pens for 8 weeks. Final body weight and nitrogen retention efficiency (NRE) were dependent on dietary protein and lipid levels and their interaction. Weight gain, body protein content, serum catalase (CAT) activity and liver glutathione peroxidase (GSH-Px) activity were dependent on dietary protein and lipid levels. Phosphorus retention efficiency was dependent on dietary protein level and interaction between protein and lipid levels. Hepatosomatic index, body lipid and energy contents, activities of superoxide dismutase (SOD) and GSH-Px in serum, and CAT activity and malondialdehyde content in liver were dependent on dietary lipid level. The final body weight and weight gain of fish fed at 490 g/kg protein level did not significantly differ from those fed at 520 g/kg protein level. The final body weight, weight gain and NRE of fish fed at 90 g/kg lipid level were higher than those fed at 60 g/kg lipid level, but did not significantly differ from those fed at 120 g/kg lipid level. The maximum weight gain occurred in fish fed the diets either containing 520 g/kg protein or 90 g/kg lipid. The body lipid content, as well as SOD and GSH-Px activities in serum, were higher in fish fed the diets with 90 and 120 g/kg lipid compared to fish fed the diets with 60 g/kg lipid. The present study reveals that the optimal dietary protein and lipid levels for large yellow croaker reared in net pens were 490–520 g/kg and 90 g/kg, respectively.

中文翻译：

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网箱饲养大黄鱼膳食蛋白质和脂质需求的重新评估

目前，世界海水鱼类养殖产量第五位的肉食性大黄鱼仍以生鱼为主，单纯配合饲料无法维持其快速生长。本研究评估了含有四种蛋白质（430、460、490和520 g/kg）和三种脂质（60、90和120 g/kg）水平的大黄鱼饲料的生长、饲料利用率、身体成分和抗氧化能力。 。重 11.4 ± 2.8 g 的鱼在网栏内用测试饲料喂养 8 周。最终体重和氮保留效率（NRE）取决于膳食蛋白质和脂质水平及其相互作用。体重增加、身体蛋白质含量、血清过氧化氢酶（CAT）活性和肝脏谷胱甘肽过氧化物酶（GSH-Px）活性取决于膳食蛋白质和脂质水平。磷保留效率取决于膳食蛋白质水平以及蛋白质和脂质水平之间的相互作用。肝体指数、体脂和能量含量、血清中超氧化物歧化酶（SOD）和GSH-Px活性以及肝脏中CAT活性和丙二醛含量均依赖于膳食脂水平。以 490 g/kg 蛋白质水平喂养的鱼的最终体重和增重与以 520 g/kg 蛋白质水平喂养的鱼没有显着差异。90 g/kg 脂质水平喂养的鱼的最终体重、增重和 NRE 高于 60 g/kg 脂质水平喂养的鱼，但与 120 g/kg 脂质水平喂养的鱼没有显着差异。喂食含有 520 g/kg 蛋白质或 90 g/kg 脂质的饲料的鱼体重增加最多。与饲喂 60 g/kg 脂质饲料的鱼相比，饲喂 90 和 120 g/kg 脂质饲料的鱼的体脂含量以及血清中 SOD 和 GSH-Px 活性较高。本研究表明，网箱饲养大黄鱼的最佳饲料蛋白质和脂质水平分别为490-520 g/kg和90 g/kg。