Isolation, identification and effect of pathogenic Vibrio parahaemolyticus VP0630 strain on non-specific immune enzyme activities of Pacific white leg shrimp Litopenaeus vannamei
LI Chunyan1，BAI Xiaohui1, LIU Yi1, ZHANG Zhenguo1, ZHANG Li2,LIU Keming1, HAO Shuang1, LUO Zhang1, YOU Hongzheng1
1.Tianjin Fisheries Research Institute, Tianjin 300221, China；2.Tianjin Animal Disease Prevention and Control Center，Tianjin 300402, China
Abstract: Dominant pathogenic bacterium VP0630 strain was isolated from hepatopancreas of diseased Pacific white leg shrimp Litopenaeusvannamei by physiological and biomedical tests, 16S rRNA gene sequence alignment, and AP4 nested PCR method. The immune enzyme activities were determined by an artificial infection experiment. The experiment consisted of a control group and a infected group, with triplicates and 30 shrimps in each parallel. The infected group shrimps were injected with 25 μL V.parahaemolyticus (3×107 CFU/mL )and the control group shrimps were injected with 0.86% sterile physiological saline. The immune enzyme activities in Pacific white leg shrimp were detected at 3, 6, 9, 12, 24, 48, 72 and 96 h. The traditional physiological and biomedical tests indicated that VP0630 strain was determined to be V.parahaemolyticus with identification percent of 99%. The AP4 nested PCR revealed that the pir-like toxins of VP0630 were positive. The artificial infection test showed that the challenged Pacific white leg shrimp had cumulative mortality rate of 78.37% at 96 h. The activities of six enzymes including lysozyme (LYS), phenol oxidase (PO), superoxide dismutase (SOD), acid phosphatase (ACP), and alkaline phosphatase (ALP), and total antioxidant capacity (T-AOC) were found to be all increased significantly within 6-12 h and subsequently decreased in serum and hepatopancreas in the infected group, most enzymes being decreased to the control level at 72-96 h, without significant change in the control group from 3 to 96 h. There were only the activities of SOD and PO in hepatopancreas and ACP in serum were decreased to a lower level than those in the control group at 96 h (P<0.05). The findings indicated that VP0630 strain isolated from naturally infected shrimps in Tianjin was V.parahaemolyticus which had strong destructive effect on the non-specific immune defense system of Pacific white leg shrimp.
李春艳, 白晓慧, 刘义, 张振国, 张丽, 刘克明, 郝爽, 罗璋, 尤宏争. 致病性副溶血弧菌VP0630株的分离鉴定及其对凡纳滨对虾免疫酶活力的影响[J]. 大连海洋大学学报, 2020, 35(4): 502-508.
LI Chunyan, BAI Xiaohui, LIU Yi, ZHANG Zhenguo, ZHANG Li, LIU Keming, HAO Shuang, LUO Zhang, YOU Hongzheng. Isolation, identification and effect of pathogenic Vibrio parahaemolyticus VP0630 strain on non-specific immune enzyme activities of Pacific white leg shrimp Litopenaeus vannamei. Journal of Dalian Ocean University, 2020, 35(4): 502-508.
2020, Vol. 35 
