Some medicinal plants have been known as immunostimulants, and the medicinal plants extract has been used to control the outbreak of the disease in aquaculture for many years. In this study, a total of 270 crucian carp (30 ± 5 g) were randomly distributed in 9 aquaria (55 cm l × 40 cm w × 50 cm h) and divided into three feeding groups including 0 (Control), 50 mg kg⁻¹ (Diet A) and 100 mg kg⁻¹ (Diet B) of salidroside. The expression of immune-related genes (IL-1β, TNFα, MYD88, CXCL-8, TGF-β, and IL-11) in the kidney had a significant increase when the crucian carp fed with Diet B for 4 weeks (P < 0.05). Meanwhile, the expression of IL-1β, TNFα, and CXCL-8 in the spleen was significantly up-regulated when the fish fed with Diet B (P < 0.05). Higher serum alkaline phosphatase (AKP) activity, catalase (CAT) activity, superoxide dismutase (SOD) activity, and complement C3 content were found in the fish which fed with salidroside-supplemented diet. Our results also proved that fish fed with salidroside-supplemented diet for four weeks, especially at a concentration of 100 mg kg⁻¹ diet, improved the protection of crucian carp against A. hydrophila. The amount of A. hydrophila in the kidney and spleen was significantly decreased in salidroside-supplemented diet groups (P < 0.05). In conclusion, the present results demonstrate that the addition of salidroside for four weeks can improve the immune response of crucian carp and increase the protection against the pathogen, especially at the concentration of 100 mg kg⁻¹ diet. The protective effect of the salidroside to the crucian carp could be used as alternatives to antibiotics for controlling fish diseases in aquaculture.

一些药用植物被称为免疫刺激剂，并且药用植物提取物已被用于控制水产养殖中疾病的爆发多年。在这项研究中，共270只cru鱼（30±5 g）随机分布在9个水族箱（55 cm l×40 cm w×50 cm h）中，并分为三个喂养组，包括0个（对照组），50 mg kg ^-1（饮食A）和100 mg kg ^-1（饮食B）红景天苷。饲喂日粮B 4周的4鱼肾脏中免疫相关基因IL-1β，TNFα，MYD88，CXCL-8，TGF-β和IL-11的表达显着增加（P  < 0.05）。同时，IL-1β，TNFα和CXCL-8的表达喂食饮食B的鱼，脾脏中的上调显着上调（P  <0.05）。在补充了红景天苷饮食的鱼中，发现其血清碱性磷酸酶（AKP）活性，过氧化氢酶（CAT）活性，超氧化物歧化酶（SOD）活性和补体C3含量更高。我们的结果也证明了鱼红景天苷补充的饮食喂养4周后，特别是在100毫克千克的浓度^-1饮食，改良的鲫鱼针对保护嗜水。量嗜水在肾脏和脾脏中红景天补充的膳食组中显著降低（P <0.05）。综上所述，目前的结果表明，红景天苷的添加持续4周可以改善cru鱼的免疫反应并增强对病原体的保护，尤其是在100 mg kg - ¹日粮中。红景天苷对the鱼的保护作用可以用作控制水产养殖鱼类疾病的抗生素的替代品。