In this study, the effects of different dietary iron levels on the growth performance, body composition and antioxidant responses were investigated in the coho salmon Oncorhynchus kisutch alevins. Six experimental diets were formulated to contain graded levels (23.7, 46.4, 59.8, 77.3, 101.7 and 127.7 mg/kg) of iron provided as FeSO₄∙7H₂O. Each diet was fed to triplicate groups of coho salmon alevins with initial mean weight of 0.35 ± 0.02 g in a flow-through rearing system for 84 days. The results showed that there was no significant difference in survival among dietary treatments. Specific growth rate (SGR) increased significantly (p < 0.05) while feed conversion rate (FCR) decreased significantly (p < 0.05) with increasing dietary iron level from 23.7 up to 101.7 mg/kg. Whole body moisture and ash showed no significant differences among dietary treatments. Fish fed the diet with 127.7 mg/kg had the significantly highest whole body protein and lipid levels (p < 0.05). Whole body and hepatic iron concentrations increased with increasing dietary iron levels (p < 0.05). However, hepatic iron concentrations were decreased when the dietary iron was higher than 77.3 mg/kg treatment. Fish fed the diet with 77.3 mg/kg had the significantly highest activities of catalase (CAT) and total superoxide dismutase (T-SOD) but the lowest malondialdehyde (MDA) activity in liver (p < 0.05). Based on the SGR, iron concentrations in the whole body and liver and CAT, T-SOD and MDA activities in liver, the optimal dietary iron requirements for coho salmon alevins were 101.7, 79.3, 75.7, 90.8, 83.6 and 68.9 mg/kg respectively.

中文翻译：

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使用生长、全身和肝脏 Fe 浓度和肝脏抗氧化酶活性评估银鲑鱼 (Oncorhynchus kisutch) alevins 的膳食铁 (Fe) 需求

在这项研究中，研究了不同膳食铁含量对银鲑Oncorhynchus kisutch alevins生长性能、身体成分和抗氧化反应的影响。配制六种实验日粮以含有分级水平（23.7、46.4、59.8、77.3、101.7 和 127.7 毫克/千克）的铁，以 FeSO ₄ ∙7H ₂ O 形式提供。每种日粮都饲喂三份具有初始平均值的银鲑鱼0.35 ± 0.02 g 在流通式饲养系统中的重量为 84 天。结果表明，饮食治疗之间的存活率没有显着差异。比生长率 (SGR) 显着增加 ( p  < 0.05) 而饲料转化率 (FCR) 显着下降 ( p < 0.05) 随着膳食铁水平从 23.7 增加到 101.7 mg/kg。全身水分和灰分在饮食处理之间没有显着差异。以 127.7 mg/kg 饲喂的鱼的全身蛋白质和脂质水平显着最高 ( p  < 0.05)。全身和肝脏铁浓度随着膳食铁水平的增加而增加（p  < 0.05）。然而，当膳食铁高于 77.3 mg/kg 治疗时，肝脏铁浓度降低。饲喂 77.3 mg/kg 日粮的鱼的过氧化氢酶 (CAT) 和总超氧化物歧化酶 (T-SOD) 活性显着最高，但肝脏中的丙二醛 (MDA) 活性最低（p < 0.05)。根据 SGR、全身和肝脏中的铁浓度以及肝脏中的 CAT、T-SOD 和 MDA 活性，银鲑鱼的最佳膳食铁需求量分别为 101.7、79.3、75.7、90.8、83.6 和 68.9 mg/kg .