Immunologic Defence Of Astaxanthin To Litopenaeus Vannamei And Water Quatity Monitoring WSSV Detecion In Shrimp Culture

In this paper, the astaxanthin was added to the feedstuff of Litopenaeus vannamei. The effect of astaxanthin upon L. vannamei was studied in terms of anti-oxidation at individual cell and molecular levels so as to give an overall appraisal of astaxanthin used to improve L. vannamei physiological function and resistance to disease. Furthermore the mechanism of astaxanthin action could be predicted. The effect of astaxanthin to L. vannamei is discussed as below:The effect of astaxanthin to L. vannamei after challenged with WSSV; the effect of astaxanthin on transcription activity of anti-oxidase gene in L. vannamei liver. Evaluation factors were selected according to various experiment aims:immunological index in hemolymph(total haemocyte counts, phagocytic percentage of haemocyte, phagocytic index, serum anti-bacterial activity, serum lysozyme activity, serum phonoloxidase activity, serum anti-superoxide radical activity); resistance to disease (the mortality of L. vannamei after challenged with WSSV); index in molecular level(SOD CAT and GPX mRNA leve 1).The results showed that astaxanthin could increase immunological index in hemol-ymph(p<0.05), the mortality of L. vannamei after challenged with WSSV was 76.3% in the supplementation level of 80 mg/kg group, the relative percent suvrival(RPS)valu e of the test group reached 23.7%. The effect of astaxanhin on gene expression of an ti-oxidase was determined using semiquantitative reverse transcription polymerase chaim reaction(RT-PCR) analysis, the results suggest that astaxanhin can impove the transcri ption acivities of anti-oxidase gene in L. Vannamei liver(p<0.05).In view of frequent occurrence of epidemic disease in shrimp culture, this paper studies on the relationship between WSSV and environmental factors in shrimp culture ponds of Fenaeus chinensis. By water quality monitoring and WSSV detection, it was shown from the analysis that when WSSV of cultured shrimp outbreak in august, dissolved oxygen in the culture ponds decreased rapidly, the variable ranges of temperature was from 24.3℃to 28.4℃in which F. chinensis can easily suffer from WSSV, pH changed acutely, ammonium and nitrate contents in the water increased suddenly. Apparently, aggravation of water quality can decrease the resistance of F. Chinensis and suffer from WSSV easily, while penaeid acute viremia survivors may die of hyperirritability.