为研究草金鱼（Carassius auratus red var.）饲料的适宜蛋白质和脂肪水平，本试验采用双因素试验设计，设4个蛋白质水平（30%、35%、40%、45%）和2个脂肪水平（5%、10%），共配制8种试验饲料，分别标记为P30L5、P30L10、P35L5、P35L10、P40L5、P40L10、P45L5、P45L10（P代表饲料蛋白质水平，L代表饲料脂肪水平）。选取初始体重为（10.20±0.61）g的草金鱼幼鱼720尾，随机分为8组，每组3个重复，每个重复30尾，以8种试验饲料饲喂8周后测定其生长性能、观赏品质、血清生化指标及氮磷排泄指标。结果表明：1）P30L10组蛋白质效率最高（2.31%），增重率、特定生长率、肥满度均较高，而饲料系数最低（1.30）。饲料蛋白质和脂肪水平对上述指标均有显著的交互作用，尤其对蛋白质效率影响极显著（P<0.01）。2）饲料蛋白质和脂肪水平的交互作用显著影响鱼体表亮度和黄度值（P<0.05）。P30L10组鱼体表亮度值最高（67.38），红度值与其他组无显著差异（P>0.05），但黄度值低，观赏品质最好。3）各组血清生化指标测定值均处于健康鱼体的参考值范围内。4）饲料蛋白质和脂肪水平的交互作用显著影响粪氮、氮排泄量、粪磷、磷排泄量（P<0.05），与P45L10组相比，P30L10组上述指标分别降低了44.44%、38.51%、47.06%、22.41%（P<0.05）。综上，饲料蛋白质水平为30%、脂肪水平为10%时，草金鱼生长性能、观赏品质最好，在保障草金鱼质量不变甚至提升的前提下，通过增加饲料脂肪水平达到节约蛋白质的目的，且氮磷排泄量最低，对水质影响最小。

In order to investigate the optimal protein and lipid levels in diets of Carassiusa uratus red var., 4 protein levels (30%, 35%, 40% and 45%) and 2 lipid levels (5% and 10%) were designed by two-way experiment design method. Eight diets were labeled by P30L5, P30L10, P35L5, P35L10 (P was protein level and L was lipid level), respectively. A total of 720 fish were used for the experiment. They were randomly divided into 8 groups with 3 replicates (30 fishes). The initial body weight was (10.2±0.61) g. After 8 weeks, growth performance, ornamental quality, serum biochemical indices and nitrogen and phosphorus excretion indices of fish were determined. The results showed as follows:1) among groups, P30L10 group had the highest protein efficiency ratio (2.31%) and the lowest feed coefficient (1.30). It also had relatively high weight gain rate, specific growth rate and condition factor. 2) The interaction of protein and lipid levels had significant effects on brightness and yellowness values (P<0.05). P30L10 group had the hightest brightness value (67.38), reddishness value was not significant compared with the other groups (P>0.05), but yellowness value was lower, therefore, the ornamental value in P30L10 group was better. 3) Serum biochemical indices of fish were in the reference values range of health fish. 4) The interaction of protein and lipid levels had significant effects on nitrogen in feces, nitrogen excretion, phosphorus in feces and phosphorus excretion. Compared with P45L10 group, nitrogen in feces, nitrogen excretion, phosphorus in feces and phosphorus excretion in P30L10 group were reduced by 44.44%, 38.51%, 47.06%, 22.41% (P<0.05), respectively. Thus, fish fed diets containing 30% protein and 10% lipid have better growth performance and ornamental quality; on the premise of keeping or improving fish quality, increasing lipid level in diets can achieve the aim of saving protein of diets, has the lowest nitrogen and phosphorus excretion, and has the least impact on water quality.