Indentification The Bacterial Pathgeon Of The Milk Disease Of Cultured Swimming Crab Portunus Tritubercularus (Portunidae) And Study On The Histopathology

The swimming crab portunus tritubercularus was became oceanic cultured objection in our country in 1982.Form the 1950s the ocenic scientist of bioscience of our country do some researches about it continuously.Because of the swimming crab grow rapid,have good ability to adapt the circumstance,suffer from little diseases,high price and the price stabilization and so on.All of those merits made its culture become hotspot and more and more popular.The crab was extensively cultured along the coast in China.However,due to the cultured scale increase,high stoching density and poor management,disease occurred frequently.especially the bacterial diseases,they often caused high mortalities.Causing serious economic losses and becoming one of the limiting factors in the sustainable development of this industry.Epidemiologic investigation from 2004 to 2005 showed that there have a terrible acute bacterial disease caused a great deal death.this disease infect rapidly,broken out large-scale;once discovered little cases, will be spread all of the pond in short time.this disease happened from September to February next year,and form September to November more often.The incidence of the disease reach to 60%,the mortality reach to 100% by and large.The gross signs of the disease crab displayed move slowly, respiration difficult,feedback slowly or no feedback to external stimulations and hidden in the bottom of pond at the beginning.Along with the development of the disease,the respiration more difficult,often floating out or climb to shore because of lack of oxygen. Several dayd later,they have no appetite,we can see muscle emulsificate from the theca of all legs.If we cut off the legs,there will be have ivory-white liquid alike milk dript naturally.Open up the tergum,a part of gills became dark,sometimes we can find sands or clay in it.The purtenance were destroyed badly,heart and digestive system destroyed lightly,usually.The hepatopancreas, germen et al,were emulsificated into milky liquid.Based on the symptom and the habit of native,we caledl the disease as"milk disease".Three pathogenic strains S1,S2,A1 were isolated from the swimming crab which were infected the milk disease at laboratory.There were Germ-negative,curved or right rods shape,they have movement ability,growth well in common culture medium. They were confirmed to be the pathogen of the disease by the artificial infection experiment.They were shown from the conventional physiological and biochemical test contrast results that S1,...