A 12-week feeding trial was conducted to determine the optimal dietary selenium requirement for coho salmon (Oncorhynchus kisutch W.) alevins. Six experimental diets (contained about 42.2% crude protein and 10.5% crude lipid) were formulated to contain selenium level of 0.07, 0.15, 0.24, 0.41, 0.75, and 1.38 mg/kg, respectively. Each diet was fed to triplicate groups of fish with initial mean body weight of 0.38 ± 0.01 g, which were randomly assigned to 18 plastic tanks (80 × 60 × 60 cm, length × width × height, water volume 240 L), and each tank was stocked initially with 50 fish. Fish were fed four times daily and used the method of overfeeding (15–20% body weight) to fish. The sampling procedure was implemented after 24 h of fasting. Results showed that specific growth rate (SGR) in 0.24, 0.41, and 0.75 mg Se/kg groups were significantly higher than those in 0.07 and 1.38 mg Se/kg groups (P < .05). There were no significant differences in hepatosomatic index (HIS), intestinal somatic index (ISI), condition factor (CF), and whole-body composition among dietary groups (P > .05). Hepatic malondialdehyde (MDA) content significantly declined with increasing dietary up to 0.41 mg Se/kg and increased as selenium further increased. The hepatic superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) significantly increased with increasing dietary selenium up to 0.41 mg/kg and decreased significantly as selenium further increased (P < .05). Fish fed diet with 0.75 mg Se/kg had the highest glutathione reductase (GR), which did not differ significantly with 0.41 and 1.38 mg Se/kg groups (P > .05) but significantly higher than those in 0.07, 0.15, and 0.24 mg Se/kg groups (P < .05). Broken-line regression analyses based on SGR, hepatic, and whole-body selenium contents indicated that the optimum dietary selenium requirements were in the range of 0.39–0.43 mg/kg for coho salmon alevins.

进行了为期 12 周的喂养试验，以确定银鲑鱼 ( Oncorhynchus kisutchW.) alevins。六种实验饮食（含有约 42.2% 的粗蛋白和 10.5% 的粗脂质）被配制为分别含有 0.07、0.15、0.24、0.41、0.75 和 1.38 mg/kg 的硒水平。每种饲料喂食三组鱼，初始平均体重为 0.38±0.01 g，随机分配到 18 个塑料罐（80 × 60 × 60 cm，长 × 宽 × 高，水量 240 L）中，每组坦克最初放养了 50 条鱼。每天喂鱼四次，并使用过量喂食（15-20% 体重）的方法捕鱼。在禁食 24 小时后实施采样程序。结果表明，0.24、0.41和0.75 mg Se/kg组的比生长率（SGR）显着高于0.07和1.38 mg Se/kg组（P< .05）。饮食组间肝体指数（HIS）、肠体指数（ISI）、状况因子（CF）和全身成分无显着差异（P > .05）。肝脏丙二醛 (MDA) 含量随着日粮增加至 0.41 mg Se/kg 显着下降，并随着硒的进一步增加而增加。肝脏超氧化物歧化酶 (SOD)、过氧化氢酶 (CAT) 和谷胱甘肽过氧化物酶 (GPx) 随着膳食硒的增加而显着增加，最高可达 0.41 mg/kg，随着硒的进一步增加而显着降低 ( P < .05)。饲喂 0.75 mg Se/kg 饲料的鱼具有最高的谷胱甘肽还原酶 (GR)，与 0.41 和 1.38 mg Se/kg 组无显着差异（P> .05) 但显着高于 0.07、0.15 和 0.24 mg Se/kg 组 ( P < .05)。基于 SGR、肝脏和全身硒含量的折线回归分析表明，银鲑鱼的最佳膳食硒需求范围为 0.39–0.43 mg/kg。