A 10‐week experiment was carried out to investigate the effects of stocking density and dietary phosphorus levels of blunt snout bream. Two culture density treatment groups (20, 60/m³) were set up, and each experimental group was fed three gradient (8.1 g/kg, 11.5 g/kg and 14.3 g/kg) phosphorus levels. The results showed that high stocking density suppressed growth performance and feed utilization in juvenile blunt snout bream. The weight gain rate, specific growth rate and protein efficiency ratio increased significantly with increasing phosphorus levels, but the feed conversion ratio exhibited the opposite trend. The moisture and ash components both achieved the maximum value while crude lipid content reached the lowest value with 14.3 g/kg phosphorus. Superoxide dismutase activity was decreased significantly with increasing dietary phosphorus levels. The expression levels of the nuclear factor erythroid 2‐related factor 2, copper zinc superoxide dismutase and Kelch‐like ECH‐associated protein 1 were dramatically affected by dietary phosphorus levels. Glutathione peroxidase 1 mRNA level was only interfered by stocking density. In addition, high dietary phosphorus and stocking density increased the total phosphorus and ammonia nitrogen emissions in water. Generally, suitable stocking density and dietary phosphorus levels have economic and environmental benefits in the production of blunt snout bream.

中文翻译：

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放养密度和日粮磷水平对少年钝嘴鲷（Megalobrama amblycephala）的生长性能，抗氧化能力以及氮和磷排放的影响

进行了为期10周的实验，研究了钝嘴鼻鱼的放养密度和日粮磷水平的影响。两个培养密度处理组（20、60 / m ³设置），并向每个实验组饲喂三个梯度（8.1 g / kg，11.5 g / kg和14.3 g / kg）的磷水平。结果表明，高放养密度抑制了幼钝鼻sn的生长性能和饲料利用率。随着磷含量的增加，增重率，比生长率和蛋白质效率比显着增加，但饲料转化率却呈现相反的趋势。水分和灰分成分均达到最大值，而粗脂质含量达到最低值，磷为14.3 g / kg。随着饮食中磷含量的增加，超氧化物歧化酶活性显着降低。核因子红系2相关因子2的表达水平 铜磷超氧化物歧化酶和类似Kelch的ECH相关蛋白1受到饮食中磷水平的显着影响。谷胱甘肽过氧化物酶1 mRNA水平仅受放养密度的干扰。此外，高日粮磷和放养密度增加了水中的总磷和氨氮排放量。通常，在生产钝嘴鲷时，合适的放养密度和日粮磷水平具有经济和环境效益。