工厂化淡水养殖凡纳滨对虾甲壳溃疡症病因与防治研究

Study on the cause and control of Carapace ulcer of Litopenaeus vannamei in factory freshwater aquaculture

为探明工厂化淡水养殖凡纳滨对虾甲壳溃疡症的病因和防控方法,进行了病原分离鉴定、毒力基因检测、攻毒试验和外用内服药敏试验。从患虾肝胰腺和发病池水中经TCBS琼脂分离纯化菌株,经培养特性、形态学、生理生化和16S rRNA基因序列分析,分别鉴定得凡隆气单胞菌F-L株和点状气单胞菌F-W株。进一步从凡隆气单胞菌F-L株中检出气溶素、细胞毒性肠毒素、酯酶、鞭毛、核酶、丝氨酸蛋白酶、热不稳定性肠毒素和弹性蛋白酶8种毒力基因,点状气单胞菌F-W株则检出气溶素、热不稳定性肠毒素、酯酶、鞭毛、弹性蛋白酶和溶血素6种毒力基因。两株菌浸泡攻毒都能引起凡纳滨对虾死亡,半数致死浓度分别为10 7.68 和10 7.8 cfu/mL,可初步判定气单胞菌为本病病原。药敏试验和防治试验结果显示,恩诺沙星内服、菌毒克外用消毒以及促进创伤愈合、调控虾池水质和虾肠肝健康有利于本病防控。此研究能为防控气单胞菌引起的凡纳滨对虾甲壳溃疡提供借鉴。

In order to determine the pathogen of the Carapace ulcer of Litopenaeus vannamei in factory freshwater aquaculture and provide the methods of prevention and treatment, analysis of isolation and identification of pathogens, virulence genes, toxicity test, the influence of phase related antibiotics and topical disinfectants on the aquatic animal were couducted. Samples were collected and isolated from the hepatopancreas of diseased shrimps and attacked water, and cultured with TCBS medium, screening for dominant strains of each group, respectively called F-L and F-W. Each group was identified based on the culture characteristics and forms, sequences of 16S rRNA gene and biochemical identification. The result of the F-L was Aeromonas veronii , and of the F-W was Aeromonas punctata . In virulence genes test, F-L strains detected 8 genes, respectively were aerA , Act , Lip , Fla , Exu , Ser , Alt and ahyB , and F-W strains had aerA , Alt , Lip , Fla , ahyB and hlyA . In toxicity test, both strains of bacteria could cause the death of Litopenaeus vannamei , and median lethal dose was 10 7.68 and 10 7.8 cfu/mL, respectively. The study would provide a basis of the effective prevention and control of Carapace ulcer of Litopenaeus vannamei caused by Aeromonas .