In this experiment, a feeding trial was performed to determine the effects of fructooligosaccharide (FOS) on growth performance, digestive enzyme activity and immune response of Japanese sea bass, Lateolabrax japonicus juveniles (initial weight 38.3 ± 0.5 g), and the fish were examined following feeding with six levels of FOS (0, 0.5, 1, 2, 4 and 6 g/kg) for 28 days. Significant enhancement of weight gain (WG) and specific growth rate (SGR) was found in fish fed 1 g/kg FOS incorporated diets (p < .05), while the feed conversion ratio (FCR) in the 1, 2 g/kg FOS groups reduced significantly compared with the control (p < .05). Besides, the crude lipid in the 4, 6 g/kg FOS groups increased significantly compared with the control (p < .05). On the other hand, the erepsin and lipase activities significantly elevated in intestine of fish fed 2 g/kg FOS (p < .05) and the lysozyme activity in serum of fish fed 2 g/kg FOS were significantly higher than that in the control (p < .05). Moreover, the alkaline phosphatase activities in serum of fish fed 0.5, 1, 2 g/kg FOS were significantly higher than in control (p < .05). Regression analysis showed that the relationships between dietary FOS levels and either SGR, FCR, erepsin or lysozyme activities were best expressed by regression equations, and the optimal inclusion levels are 1.37, 1.80, 3.06, 3.11, 1.93 and 1.80 g/kg for SGR, FCR, erepsin, lipase, lysozyme and total superoxide dismutase activities, respectively. Overall, this study revealed that FOS incorporated diets could beneficial for L. japonicus culture in terms of increasing the growth, digestion and immune activities. Under the present experimental condition, the optimal supplementary level of FOS in the diet of L. japonicus is 1–3 g/kg.

中文翻译：

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低聚果糖饲喂日本鲈鱼的生长性能、消化酶活性和免疫反应

在本实验中，进行了一项饲喂试验，以确定低聚果糖 (FOS) 对日本鲈鱼、Lateolabrax japonicus 幼鱼（初始体重 38.3 ± 0.5 g）的生长性能、消化酶活性和免疫反应的影响，并对鱼进行了检查在用六种 FOS（0、0.5、1、2、4 和 6 g/kg）喂养 28 天后。喂食 1 g/kg FOS 饲料的鱼的体重增加 (WG) 和比生长率 (SGR) 显着提高 (p < .05)，而饲料转化率 (FCR) 在 1, 2 g/kg与对照组相比，FOS 组显着减少 (p < .05)。此外，与对照组相比，4、6 g/kg FOS 组的粗脂质显着增加（p < .05）。另一方面，饲喂 2 g/kg FOS 的鱼的肠内肠蛋白酶和脂肪酶活性显着升高 (p < .05)，饲喂 2 g/kg FOS 的鱼血清中的溶菌酶活性显着高于对照 (p < .05) ）。此外，饲喂 0.5、1、2 g/kg FOS 的鱼血清中碱性磷酸酶活性显着高于对照（p < .05）。回归分析表明，日粮 FOS 水平与 SGR、FCR、erepsin 或溶菌酶活性之间的关系最好通过回归方程表达，SGR 的最佳添加水平为 1.37、1.80、3.06、3.11、1.93 和 1.80 g/kg，分别为 FCR、肠蛋白酶、脂肪酶、溶菌酶和总超氧化物歧化酶活性。总体而言，这项研究表明，在增加生长方面，加入 FOS 的饮食可能有益于 L. japonicus 培养，消化和免疫活动。在目前的实验条件下，金枪鱼饲料中FOS的最佳添加量为1-3 g/kg。