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为研究无乳链球菌感染吉富罗非鱼后病原菌在体内的动态分布规律,本研究采用q RT-PCR方法,以人工感染无乳链球菌的吉富罗非鱼抗病家系组和易感家系组为测试对象,检测了感染后不同时间段两组的肝脏、脾脏、前肾及脑组织的无乳链球菌含量。结果表明:(1)抗病组和易感组出现死亡时间均主要集中在12~96 h,死亡率分别为25%和61.9%;(2)感染后3 h抗病组和易感组的肝脏、脾脏、前肾及脑组织的无乳链球菌数量逐渐增加,其中脑组织达到高峰值分别为感染后72 h和18 h,无乳链球菌含量分别为(11 366.86±739.04)copies/μL和(16 371.59±655.65)copies/μL,96 h后两组体内的无乳链球菌浓度逐渐减少,感染后144 h停止死亡,感染后30 d存活的个体中4个组织的无乳链球菌浓度逐渐下降至感染初期水平。本研究结果为罗非鱼无乳链球菌病的药物防治及抗病育种提供了技术依据。
In order to study the dynamic distribution of pathogen in Streptococcus agalactiae infected by Streptococcus agalactiae in the body, qRT-PCR method was used in this study. As the test object, the content of Streptococcus agalactiae in the liver, spleen, anterior kidney and brain tissue of the two groups was tested at different time points after infection. The results showed that: (1) The time of death in both disease-resistant and susceptible groups was mainly between 12 and 96 h with mortality rates of 25% and 61.9%, respectively; (2) The number of Streptococcus agalactiae in liver, spleen, anterior kidney and brain increased gradually, and the peak value of brain tissue peaked at 72 h and 18 h after infection, respectively. The content of Streptococcus agalactiae was (11366.86 ± 739.04) copies / μL And (16 371.59 ± 655.65) copies / μL, respectively. After 96 h, the concentration of Streptococcus agalactiae in both groups gradually decreased and died after 144 h. The concentrations of Streptococcus agalactiae in the four tissues at 30 d after infection Gradually decreased to the initial level of infection. The results of this study provide technical basis for drug prevention and disease-resistant breeding of S. agalactiae in tilapia.