黄芪多糖对草鱼非特异免疫功能的影响

Effect of astragalus polysaccharides on nonspecific immunity of grass carp(Ctenopharyngodon idellus)

旨在探讨饲料中添加不同水平的黄芪多糖(Astragalus polysaccharides,APS)对草鱼(Ctenopharyngodon idellus)非特异性免疫指标的影响。将600尾健康草鱼随机分成Ⅰ-Ⅳ组,在基础饲料中分别添加黄芪多糖0、10.0、30.0、50.0 mg/(kg·d),于D0、D8、D15、D22、D29测定草鱼白细胞的吞噬百分比(PP)、吞噬指数(PI)及血清总超氧化物歧化酶(T-SOD)、过氧化氢酶(CAT)与溶菌酶(LSZ)活力等指标,D29时对4组草鱼进行嗜水气单胞菌(Aeromonas hydrophila)攻毒实验。结果表明:与对照组相比,饲料中添加实验剂量的黄芪多糖可不同程度提高供试草鱼血液白细胞的吞噬百分比和吞噬指数,各实验组草鱼血清中T-SOD、CAT、LSZ活性均呈增加趋势,投喂实验剂量的黄芪多糖均可显著降低嗜水气单胞菌攻毒后草鱼的死亡率(P<0.05)。研究表明,在饲料中添加适宜水平的黄芪多糖可提高草鱼的非特异性免疫功能和对嗜水气单胞菌感染的抵抗力,每千克鱼体质量的推荐剂量为10~30 mg/d。

This experiment was conducted to investigate the effect of astragalus polysaccharides （APS） on nonspecific immunity of grass carp （Ctenopharyngodon idellus）.600 healthy grass carps were randomly divided into Group Ⅰ-Ⅳ, fed with the basal diet added with 0, 10.0, 30.0, 50.0 mg APS per kilogram body weight everyday respectively.Phagocytic percentage （PP）, phagocytic index （PI） of leukocytes in blood and the activities of total superoxide dismutase （T-SOD）, catalase （CAT） and lysozyme （LSZ） in serum were determined on D0, D8, D15, D22 and D29.On the 29th day of feeding, 20 grass carps of each group were infected by Aeromonas hydrophila and mortalities were recorded.The results indicated that APS added in diets can increase PP and PI of leukocytes, and enhance the activities of serum T-SOD, CAT, LSZ.The mortality rate of grass carps infected by A.hydrophila was significantly decreased when fed by APS （P〈0.05） and the protective rate of Group Ⅱ-Ⅳ were 54.3%±6.4%, 52.9%±12.5% and 44.2%±4.8% respectively.It suggested that APS can enhance nonspecific immunity function of grass carp, and the effect of low dose was superior to high dose.The recommended dose of APS added to the diet applying in aquaculture was 10-30 mg/d per kilogram body weight.