养殖大菱鲆黑瘦症的病原菌鉴定及杀菌中草药筛选

摘要

从患黑瘦症的大菱鲆幼体内分离得到一株优势菌株,人工感染实验证实其为大菱鲆致病菌,并经过生理生化及16S rDNA序列分析鉴定为灿烂弧菌Vibrio splendidus.组织病理学显示,病鱼的肝脏、肾脏、脾脏、肠道及脑均呈现不同程度的组织破坏.用煎煮法提取11种常用中草药成分,测定该致病菌对中草药的杀菌效果.实验表明,五倍子和白头翁的杀菌效果最好,黄柏、穿心莲次之,当归、党参、杜仲、秦皮、金银花、乳香和没药的杀菌效果最差.以五倍子、白头翁为主要成分的初步治疗试验证明,药浴和口服给药可有效治愈大菱鲆苗期的黑瘦症.%Dark-thin syndrome often occurred at stages of larval turbot Scophthalmusrnmaximus, causing lower metamorphosis and more than 80% of mortality. One bacterial strain was isolated from the diseased larvae, and it was confirmed to be the pathogen causing the disease through artificial infection tests. The pathogenic bacterium was identified as Vibrio splen-didus by conventional physiological and biochemical tests as well as 16S rDNA sequence analysis. In addition, histopathological studies demonstrated that the bacterium could cause infectious changes in the liver, kidney, spleen, intestine and brain. The effective components of 11rn Chinese herbs were extracted respectively by the methond of decoction, and they were tested for the susceptibility against V. splendidus. The results showed that Galla chinensis and Radix pulsatillae had the best inhibitory effect on the bacterium, with minimal bactericidal concentration (MBC) of 25mg/ml. MBC for both Phellodendronchinen.se and Herba andrographitis was 50mg/ml. While Chinese angelica , Radix codonopsisand , Eucommia bark , Codex fraxini , Flos Inicerae , Bosxvellia carterii and Commiphora molmol had the weakest inhibition effect with MBC more than l00mg/ml. The preliminary tests indicated that G. chinensis and R. pulsatillae were good treatments by oral and immersion administration.