The aim of the study was to evaluate the effects of dietary leucine level on growth performance, intestinal antioxidant status and immune response involved in Nrf2 and NF-κB signaling pathway in juvenile golden pompano (Trachinotus ovatus). A total of 450 juvenile golden pompano (9.15 ± 0.04 g) were fed three isonitrogenous diets with graded leucine levels [1.25% (control), 2.77% and 5.84%] for 8 weeks. The results showed that, compared with the control group, the WG was significantly improved in fish fed with 2.77% of dietary leucine (P < 0.05), and the 5.84% dietary leucine group had a tendency to increase. Compared to control group, 5.84% dietary leucine group significantly decreased the moisture and ash contents of whole body (P < 0.05), meanwhile, 2.77% dietary leucine group significantly decreased moisture content of whole body, but significantly improved the whole body crude lipid content (P < 0.05). Compared with the control group, the ALP level was significantly improved in fish fed with 2.77% of dietary leucine (P < 0.05). Inversely, the AST and ALT activities were significantly decreased in fish fed with 2.77% dietary leucine level (P < 0.05). Compared with the control group, GPx, T-AOC, SOD activities in group of 2.77% dietary arginine level were significantly increased (P < 0.05). However, MDA level showed a reverse trend, which was significantly decreased in fish fed with 2.77% dietary leucine level (P < 0.05). 2.77% dietary leucine levels significantly increased the relative expressions of Nrf2, HO-1, Cu/Zn-SOD, Mn-SOD and CAT (P < 0.05). In contrast, the relative expression of Keap1 showed a converse trend. Compared with the control group, the relative expressions of NF-κB, TNF-α and IL1-β were significantly lowered in fish fed with 2.77% of dietary leucine (P < 0.05). Additionally, 2.77% dietary leucine level significantly improved the relative expressions of TGF-β and IL-10 (P < 0.05). The 2.77% dietary leucine level significantly increased the muscular thickness compared with 5.84% dietary leucine level (P < 0.05). Furthermore, compared with the control group, the villus height and goblet cell counts were significantly improved in fish fed with 2.77% of dietary leucine (P < 0.05). These results indicated that the optimum dietary leucine plays an important role in promoting growth, enhancing antioxidant and immunity to maintain the intestinal health status of juvenile golden pompano.

这项研究的目的是评估膳食亮氨酸水平对幼年金mp（Nutf2）和Nrf2和NF-κB信号通路所涉及的生长性能，肠道抗氧化剂状态和免疫应答的影响。总共向450尾幼年金po鱼（9.15±0.04 g）喂食了三个等氮日粮，它们的亮氨酸水平分别为[1.25％（对照），2.77％和5.84％]，持续8周。结果表明，与对照组相比，饲喂2.77％日粮亮氨酸的鱼的WG明显提高（P  <0.05），而5.84％日粮亮氨酸的组有增加的趋势。与对照组相比，5.84％的饮食亮氨酸组显着降低了人体的水分和灰分含量（P <0.05），同时，饮食亮氨酸组的2.77％显着降低了人体的水分含量，但显着提高了人体的粗脂肪含量（P  <0.05）。与对照组相比，饲喂2.77％日粮亮氨酸的鱼的ALP水平显着提高（P  <0.05）。相反，饲喂2.77％日粮亮氨酸水平的鱼的AST和ALT活性显着降低（P  <0.05）。与对照组相比，日粮精氨酸水平为2.77％的组GPx，T-AOC，SOD活性显着升高（P  <0.05）。然而，丙二醛水平呈反向趋势，在饲喂2.77％日粮亮氨酸水平的鱼类中，丙二醛水平显着下降（P <0.05）。膳食亮氨酸含量为2.77％，显着增加了Nrf2，HO-1，Cu / Zn-SOD，Mn-SOD和CAT的相对表达（P  <0.05）。相反，Keap1的相对表达呈相反趋势。与对照组相比，饲喂2.77％日粮亮氨酸的鱼中NF-κB，TNF-α和IL1-β的相对表达显着降低（P  <0.05）。此外，饮食中的亮氨酸含量为2.77％，可显着改善TGF-β和IL-10的相对表达（P  <0.05）。饮食中亮氨酸水平为2.77％，而饮食中亮氨酸水平为5.84％（P <0.05）。此外，与对照组相比，饲喂2.77％日粮亮氨酸的鱼的绒毛高度和杯状细胞计数显着改善（P  <0.05）。这些结果表明，最佳饮食亮氨酸在促进生长，增强抗氧化剂和免疫力以维持少年金po鱼的肠道健康方面起着重要作用。