养殖裸盖鱼(Anoplopoma fimbria)疥疮病病原菌的分离与鉴定

裸盖鱼(Anoplopoma fimbria)是一种名贵的冷水经济鱼类,已在我国北方地区开展小规模的工厂化繁育和养成.目前,我国关于裸盖鱼的病害研究仍是空白.本研究对山东烟台一养殖场自然发生疥疮病的裸盖鱼进行了病原分析,从发病鱼体内分离得到形态一致的优势菌株,命名为AF-1,并对其进行了致病性检测、菌种鉴定及药物敏感性研究.人工感染实验证明,AF-1对裸盖鱼有致病性,呈现症状与自然发病状态一致;结合形态观察、革兰氏染色、生理生化特征、16S rRNA和gyrB基因序列进化树分析,将AF-1鉴定为杀鲑气单胞菌(Aeromonas salmonicida);药物敏感性实验结果显示,AF-1对青霉素、阿莫西林、头孢噻吩等13种抗生素具有耐药性,对氟苯尼考、氟甲喹等16种抗生素敏感.综上所述,本研究首次报道了我国养殖裸盖鱼感染杀鲑气单胞菌病例,为裸盖鱼养殖过程中的疾病防控和疫苗开发提供了参考.

Isolation and Identification of Aeromonas salmonicida Associated with Furunculosis in Cultured Sablefish (Anoplopoma fimbria)

Sablefish (Anoplopoma fimbria), also known as black cod, is a sleek, black-skinned and valuable cold water benthic fish species that lives in the north Pacific Ocean. They possess high content of unsaturated fatty acids. Sablefish have been cultured in British Columbia of Canada, and in recent years, they were introduced into the aquaculture industry in Shandong Province in north China. In this study, we reported the observation of furunculosis found in cultured sablefish in China. AF-1, a strain of bacterial pathogen was isolated from the diseased sablefish. Sablefish infected with this bacterium showed typical symptoms of furunculosis such as subcutaneous hemorrhage in the abdomen and the fin, abscess, ulcer and liver congestion. AF-1 was confirmed to be the pathogen of sablefish furunculosis through the artificial injection experiment, in which the injected fish showed the same symptoms. A series of methods including biochemical and biophysical tests and phylogenetic analysis of 16S rRNA and gyrB genes were used to identify the pathogen. The API ID32E results showed that AF-1 belonged to Aeromonas sp. The 16S rRNA and gyrB genes were amplified and sequenced, and the submission numbers were KU359246 and KU362567. Phylogenetic analysis of gene sequences showed that AF-1 was Aeromonas salmonicida. The chemotherapeutant sensitivity test showed that AF-1 was resistant to 13 antibiotics such as penicillin, amoxicillin and cephalothin, but was sensitive to another 16 antibiotics such as fumequine and florfenicol. According to the antibiotics sensitivity test result, florfenicol was added into diets to control furunculosis in sablefish. Our study indicated that A. salmonicida could infect cultured sablefish in our country, and provided information on the disease control in cultured sablefish.