溶藻弧菌(Vibrio alginolyticus)、哈维氏弧菌(Vibrio harveyi)、副溶血弧菌(Vibrio parahaemolytic-us)是引起大黄鱼(Pseudosciaena crocea)溃疡病的3种主要致病菌.将试验大黄鱼随机分成4组,分别腹腔注射哈维氏弧菌、溶藻弧菌、副溶血弧菌和灭菌生理盐水,在感染后的不同时间采样,通过白细胞数量、白细胞分类计数、NBT阳性细胞数量以及溶菌酶活力的变化趋势来探讨3种致病弧菌感染对大黄鱼非特异性免疫功能的影响.结果表明,大黄鱼各项血液指标的变化主要发生在感染后的1~7 d.在人工感染的初期,各实验组大黄鱼外周血的白细胞数量、NBT阳性细胞数量呈现先增加后降低的趋势,淋巴细胞、嗜中性粒细胞百分比显著降低(p〈0.05),单核细胞百分比显著提高(p〈0.05);随着时间的延长,白细胞数量开始下降;淋巴细胞、嗜中性粒细胞百分比有所上升,7 d以后各类血细胞数量变化不显著.其中哈氏弧菌感染组在白细胞数量、NBT阳性细胞数量等多个指标上的变化最为明显.血清中溶菌酶活性显著高于脾组织,鱼体受感染后两者溶菌酶活性均较对照组有显著提高,不同致病菌与大黄鱼非特异性免疫功能之间呈现一定的时效差异.研究认为反映鱼体受感染后从应激反应发生至非特异性免疫功能的发挥主要发生在病原菌感染前期,不同致病菌与大黄鱼非特异性免疫功能之间呈现一定的时效差异.
Ulcer disease,which caused by the pathogens such as Vibrio alginolyticus,Vibrio harveyi and Vibrio parahaemolyticus according to the researches,is the most common,wide spreading and harmful disease of cage cultured croaker,Pseudosciaena crocea.In this research,we set 3 experimental groups with injections of 0.2 cm3 Vibrio harveyi,Vibrio alginolyticus and Vibrio parahaemolyticus,respectively,besides a control group treated with a same dose of normal saline.At the intervals of 0,1,2,4,7,10,13,16 and 20 days after infection,blood leucocytes,NBT-positive cells and lysozyme level were taken and measured for the influence on the croaker's non-specific immunity function under the pressure of 3 pathogenic vibrio.The results show that the change of blood physiological signs in the croaker mainly occurred 1~7 days after infection.At the initial stage,each experimental group had a significantly increase in white blood cell and NBT positive cell number(p0.05).The percentage of lymphocyte and neutrophilic granulocyte decreased with an increasing percentage of monocyte(p0.05).Thereafter,white blood cells started to decline and the percentage of lymphocyte and neutrophilic granulocyte started to increased.Seven days after infection,the number of varied blood cells didn't change significantly any more,and the group infected by vibrio heavily had an obvious significant change of blood physiological signs and NBT positive cell number.The activity of lysozyme in serum was higher than spleen,but both of them were first increased and then decreased,at last they went to an accordant tendency.So we conclude that the activation of stress response and non-specific immunity function's happened at the early stage of infection.The pathogenic vibrio showed different influences,with a time lag,on the non-specific immunity.