Six graded levels of dietary alfalfa Medicago falcata L. powder (0, 5, 10, 15, 20 and 25 g/kg diet, respectively) were fed to Lateolabrax japonicus (initial body weight: 11.41 ± 0.06 g; initial body length: 10.33 ± 0.12 cm) in triplicate groups for 4 weeks in a flow-through system to investigate the effects of alfalfa powder on the growth performance, nonspecific immunity and digestive enzyme activity. The results showed that alfalfa powder reduced the feed conversion ratio (FCR), with the lowest value obtained at 20 g/kg diet among all groups (p < 0.05). The serum total soluble protein (TP) content, activity of lysozyme (LZM) and total superoxide dismutase (T-SOD) were increased first then remained more or less stable; the alkaline phosphatase (AKP) was maintained stable first then sharply increased with the increasing dietary alfalfa powder levels. The trypsin and lipase (LPS) activity of fish was significantly increased at 20 g/kg diet, compared to the control group (p < 0.05). Regression analyses of FCR, TP, LZM, T-SOD, LPS and trypsin indicated that the optimal supplement amount was 17.75–21.48 g/kg diet. Combined with the significant difference analyses obtained from the current study, we suggest the additional amount of alfalfa should be about 20 g/kg diet.

六种等级的苜蓿苜蓿苜蓿苜蓿粉（分别为0、5、10、15、20和25 g / kg饮食）饲喂日本乳草（初始体重：11.41±0.06 g；初始体重：10.33）在流通系统中一式三份，每组±0.12 cm）放置4周，以研究苜蓿粉对生长性能，非特异性免疫和消化酶活性的影响。结果表明，苜蓿粉降低了饲料转化率（FCR），在所有组中以20 g / kg日粮获得最低值（p <0.05）。血清总可溶性蛋白（TP）含量，溶菌酶（LZM）活性和总超氧化物歧化酶（T-SOD）先升高，然后基本保持稳定。碱性磷酸酶（AKP）首先保持稳定，然后随着日粮苜蓿粉含量的增加而急剧增加。与对照组相比，在20 g / kg饲料中，鱼的胰蛋白酶和脂肪酶（LPS）活性显着增加（p  <0.05）。对FCR，TP，LZM，T-SOD，LPS和胰蛋白酶的回归分析表明，最佳补充量为17.75–21.48 g / kg日粮。结合从当前研究获得的显着差异分析，我们建议苜蓿的额外添加量应为20 g / kg饮食。