Analysis Of Sequence Variability Among White Spot Syndrome Virus (WSSV) And Selection Of Four Immunoenhancement Against WSSV

White spot syndrome virus (WSSV) is one of the most serious shrimp dsDNA viruses.Since the first explosion of cultured shrimp death in Taiwan during1992, WSS has exploded in nearly all shrimp culture areas all around the world and caused huge economic losses to the industry of world shrimp culture. Elucidating the mechanisms of epidemiology would contribute to the control of WSSV. In recent years, several outbreaks of shrimp disease happened frequently in coastal areas of Jiangsu, it caused mass mortalities of cultured Exopalamon carincauda.PCR (polymerase chain reaction) had been performed to analysis the epidemiology of WSSV at the molecular level in this study. We used a typical onset of Exopalaemon carinicauda which carried WSSV as the experimental object, and extracted the genome used8pairs of special primers for the variable loci to detect the differences between the isolated strains with the3whole genome sequences published by the GenBank or others. From the experimental we found that8sequences of the isolates had differences mainly manifest in a number of different repeat unit, single nucleotide mutation, single nucleotide polymorphism and single nucleotide insertion. The results were compared with the other isolates, variable region sequences were significantly different, envolutionary relationship between DY001isolate and Taiwan isolate, Thailand isolate was closer than the others. DY001isolate is relative independent evolution with the other isolate from a common ancestor by deletion/insertion/single nucleotide polymorphisms of the genome, and there were many similarities among these loci. But DY001is difference from WSSV-TH、WSSV-CH and WSSV-TW, these results indicated that the WSSV carried in Exopalaemon carinicauda in Jiangsu has its unique characteristics.Exopalamon carincauda were fed with diet supplemented0.5%trehalose,0.5%chitosan,1.0%propolis and1.0%photosynthetic bacteria respectively, and then we analysed the effects of nonspecific immunity function. Exopalamon carincauda were divided into10groups, including two groups control for feeding with normal diet and others feeding enhencments. The Exopalamon carincauda in the experiment were weight at3.33±1.24g, length in3.50±1.21cm. We had fed them30days in the experiment, we sampled ten times3th,6th,9th,12th,15th,18th,21th,24th,27th and30th d. We detected peroxidase activity (POD), acid phosphatase (ACP), alkaline phosphatase (AKP) and superoxide dismutase (SOD) in using muscle tissue homogenate and discussed effects from these four substances as immunologic agents to the nonspecific immune of Exopalamon carincauda. The experimental results showed that, in a certain period trehalose, chitosan, propolis and photosynthesis bacteria could improve activities of AKP, ACP, POD and SOD in the Exopalaemon carinicauda tissues. And trehalose and chitosan on Exopalaemon carinicauda tissue in AKP, ACP, SOD and POD activity were significant effects. And groups of propolis and photosynthetict were better than groups of trehalose and chitosan. The result indicated that propolis and photosynthetic bacteria can be used as two ideal adjuvant for enhance immune respond of Exopalaemon carinicauda. Therefore,we suggested that photosynthetic bacteria can improve the nonspecific immunity level of Exopalae-mon carinicauda and can be as immunity enhancement agent in Exopalaemon carinicauda,it will have a good application prospect.