The Primary Research On Specialized Strain Of Macrobrachium Rosenbergii In Disease-resistant

Macrobrachium rosenbergii was introduced into China from Japan in1976, itscultivation hm2s expanded rapidly, and it hm2d become China’s major freshwateraquaculture shrimp species.However, in recent years, with the M.rosenbergii’s farmingconstant expansion and aquaculture water pollution increasing, various diseases followed,bring a serious hm2rm to the M.rosenbergii aquaculture.At present, facing various diseasesof M.rosenbergii farming industry, there main use antibiotics to prevent and treat, but theuse of drug exist safety and resistance issues, so the new specialized strain ofM.rosenbergii about disease-resistant breeding is very important.In this study, the M.rosenbergii disease-resistant breeding is for the Vibrioalginolyticus, the M.rosenbergii which hm2ve atresia breeding for15years coming fromShm2nghm2i Shencao Special Fisheries Development Company.Through determining andanalysing27morphology shm2pe indicators of391M.rosenbergiis，dividing M.rosenbergiiinto nine groups. In accordance with the first abdominal segment wid th and body lengthratio the M.rosenbergii are divided into A₁（less thm2n0.17299）,A₂（0.17299～0.18893）and A₃（larger thm2n0.18893）；in accordance with the height of the first abdominalsegment and body length ratio the M.rosenbergii are divided into B₁（less thm2n0.15008）,B₂（0.15008～0.17427）and B₃（larger thm2n0.17427）；inaccordance withtheCarapace and body length ratio the M.rosenbergii are divided into C₁（less thm2n0.19536）,C₂（0.19536～0.22105）and C₃（larger thm2n0.22105）,and according to theselection criteria directional selecting the base population of M.rosenbergii and diseaseresistance groups.Kinds of bacteria were isolated and purified from M.rosenbergii broodstock breedingwater, through infection experiments selecting the Vibrio alginolyticus as the infectionbacteria of the study. Through infection experiments of different patterns of infection,different levels of infection and different infection agents, determining inject infection wasthe best method of infection, and selecting104CFU/g as the best experimental infectiondose. Through determining CAT,T-SOD,GSH-px,ACP and AKP of M.rosenbergii muscleand hepatopancreas after infecting, the results showed thm2t: Only T-SOD and ACPactivity of muscle tissue there hm2d significant differences （p <0.05） after infecting20d.Within96h,CAT, T-SOD of muscle and AKP activity rose first and then dropped，thechm2nges were significantly； T-SOD and GSH-px activity of hepatopancreas rosegradually, the Chm2nges were very significantly; only at48h the ACP activity of muscletissue was significantly lower thm2n the control （p <0.05）. The results of this studyindicated thm2t: immune enzyme activities of Macrobrachium rosenbergii were infectedby Vibrio alginolyticus more significantly, among them,CAT, T-SOD, GSH-px and AKPare sensitive indexes.Through determining the number of Vibrio alginolyticus in M.rosenbergii tissueswhich were survival after infecting injection, finding thm2t the number of Vibrioalginolyticus in the tissues showed a rising trend, while five enzymes（CAT,T-SOD,GSH-px,AKP,ACP） activities hm2ve dramatic chm2nges in preliminary afterinfection and at a low level the late, especially the T-SOD and GSH-px activities inhepatopancreas and AKP activity in muscle, late enzyme activity significantly lower thm2npre-infection, this reflected thm2t a certain relationship between the Vibrio alginolyticusnumber and immune activity, the two complement each other reflecting thedisease-resistance strength of the M.rosenbergii.In addition, through infection on offspring of A₂,A₃,B₂,B₃,C₂and C₃with104CFU/g,finding thm2t the B₃M.rosenbergii hm2s the highest survival rate，the female shrimpsurvival rate was55.8%, there hm2s significant difference compared to A₂, A₃, B₂, C₂andC₃; the male shrimp survival rate was36.1%, significantly higher thm2n A₃. Therefore setB₃for the strongest disease-resistance type initially. Again infecting a number of B₃M.rosenbergii with102CFU/g, from the survival shrimp selecting the health M.rosenbergiiwhich large,strong vitality and the body surface without injury. These M.rosenbergii as thedisease-resistance broodstock, each group1male and4females, putting into a broodstockbreeding barrel cultivate, a total of three groups are elected to remain. So three M.rosenbergii hm2lf-sib disease-resistance family2011-12-B₃-0-1，2011-12-B₃-0-2and2011-12-B₃-0-3are established initially.