中国对虾黑鳃病病原及病变机理的研究

Studies on the Pathogens and Pathogenesis of Black Gill diseases of Penaeus chinensis

采用组织、扫描电镜和透射电镜方法 ,研究了中国对虾海虾和养殖虾的黑鳃病的发病率、病原和病变机理。发现不管是海虾还是养殖虾均有黑鳃病个体 ,海虾患黑鳃病的比例为 2 0 % ;养殖虾患黑鳃病的比例为 90 %。引起黑鳃病的病原有弧菌、丝状菌、镰刀菌、链格孢、聚缩虫、病毒等。另外水质污染和污物等也能引起对虾黑鳃病。病原生物多数具有固着特点 ,其致病机理是 :大量病原的附着使鳃的代谢功能受阻、通透性降低 ,进而鳃组织坏死 ;病原产生的毒素或分泌的酶类使鳃组织受毒害而坏死 ;一些有毒的金属物或化学物质附着于鳃上 ,使鳃失去代谢能力而坏死。失去代谢能力的鳃 ,首先表面几丁质层出现混浊 ,层次消失 ,进而变黑 ,向表皮层内部侵入 ,使鳃组织的细胞溃散 ,进而出现空泡 ,最后鳃组织变脆 。

By using histological and electron microscopic methods,we studied the incidence,pathogens and pathogenesis of the black gill diseases of Penaeus chinensis.Both wild and farmed shrimps have individuals with black gill diseases at percentages of 20% and 80%,respectively.The pathogens include Vibrio sp.,Leucothrix sp.,Fusarium sp.,Altamaria sp.Zoothanium sp.,virus,etc.Water pollution and dirt can also result in black gill diseases.Most of the pathogens have the ability to adhere themselves on the surface of shrimp gills.The adhered pathogens hinder the gills from metabolizing,and reduce the permeability of the gills,which lead to necrosis of the gill tissue.The toxins and enzymes secreted by some of the pathogens,and toxic metals or other chemical materials can also reduce the metabolizing ability of the gills and eventually lead to necrosis of the gill tissue.When the gills lose the metabolizing ability,there will appear turbidity in the chitinous cuticle and the distinct gradation of the cuticular layers disappear,then the gills become black.The pathological changes intrude into the gill tissue,and the cells are destroied,then there appear empty cavities in the gill tissue which will eventually become fragile and rupture.