title: The immune response of the white shrimp Litopenaeus vannamei and its susceptibility to Vibrio infection in relation with the moult cycle.
abstract: The white shrimp Litopenaeus vannamei (8.0-14.4 g) was examined for haemocyte count, phenoloxidase activity, respiratory burst (release of superoxide anion), phagocytic activity, and clearance efficiency to the pathogen Vibrio alginolyticus in relation with moult cycle (postmoult, A, B; intermoult, C; premoult, D(0)/D(1)D(2)/D(3)). Granular cells were the highest at C and D(0)/D(1)stage, and the lowest at A stage. Hyaline cells and THC (total haemocyte count) were higher at C stage, but lower at postmoult stages. Phenoloxidase activity was the highest at C stage, and the lowest at A stage. Respiratory burst was lower at A stage. Phagocytic activity of shrimps against V. alginolyticus decreased significantly at postmoult and premoult stages. Additionally, the clearance efficiency of shrimps to V. alginolyticus was significantly lower for shrimps at A stage than those at C stage. In another experiment, L. vannamei at different moult stages were injected with tryptic soy broth (TSB)-grown V. alginolyticus (1x10(5)cfu shrimp(-1)) and then held in 34% seawater. After 10 h, the mortality of V. alginolyticus-injected shrimps was significantly higher for shrimps at postmoult stage than those at intermoult stage. Over 48-120 h, the mortality of V. alginolyticus-injected shrimps was 50.0%, 33.3% and 40.0% at postmoult, intermoult and premoult stage, respectively. It is concluded that L. vannamei showed a decrease in resistance at A stage through a reduction of its haemocyte count, phenoloxidase activity, respiratory burst, phagocytic activity and clearance efficiency against V. alginolyticus.
authors.affiliation: Department of Aquaculture, College of Life and Resource Sciences, National Taiwan Ocean University, Keelung, 202, Taiwan, ROC.
authors.forename: Chun-Hung
authors.initials: CH
authors.lastname: Liu
authors.forename: Su-Tuen
authors.initials: ST
authors.lastname: Yeh
authors.forename: Sha-Yen
authors.initials: SY
authors.lastname: Cheng
authors.forename: Jiann-Chu
authors.initials: JC
authors.lastname: Chen
mesh_terms: D000818:Animals; D001772:Blood Cell Count; D004198:Disease Susceptibility / Q000276:immunology; D006434:Hemocytes / Q000276:immunology; D018978:Molting / Q000276:immunology*; D014442:Monophenol Monooxygenase / Q000378:metabolism; D033561:Penaeidae / Q000276:immunology* / Q000382:microbiology*; D010587:Phagocytosis / Q000276:immunology; D016897:Respiratory Burst; D044149:Vibrio alginolyticus
chemical_list: D014442:Monophenol Monooxygenase