Effect of nitrite on immune response of Taiwan abalone Haliotis diversicolor supertexta and its susceptibility to Vibrio parahaemolyticus.
Taiwan abalones Haliotis diversicolor supertexta held in 30% per thousand seawater and 26 degrees C were injected with tryptic soy broth (TSB)-grown Vibrioparahaemolyticus (1.6 x 10(5) CFU [colony-forming units] abalone(-1)), and then placed in water containing different concentrations of nitrite-N (nitrite as nitrogen): 0.01 mg l(-1) (control), 1.05, 3.04, 5.10 and 10.06 mg l(-1). Mortality of the abalones increased in direct parallel to ambient nitrite-N concentration. Over 12 to 48 h, the mortality of V. parahaemolyticus-injected abalones held in 3.04 mg l(-1) nitrite-N was significantly higher than that of abalones in the control solution. Abalones that had been exposed to control, 0.96, 2.95, 5.03 and 10.16 mg l(-1) nitrite-N for 24, 72 and 120 h were examined for THC (total hemocyte count), phenoloxidase activity, respiratory bursts (release of superoxide anion), phagocytic activity, and clearance efficiency of V. parahaemolyticus. The THC increased in abalone after 72 h exposure to 0.96 and 2.95 mg l(-1) nitrite-N, but decreased in abalones after 24 h exposure to 5.03 and 10.16 mg l(-1) nitrite-N. Phenoloxidase activity and respiratory bursts increased, while phagocytic activity and clearance efficiency decreased in abalones exposed to > or = 0.96 mg l(-1) nitrite-N for 24 h. It is concluded that nitrite-N in water at concentrations as low as 0.96 mg l(-1) weakens the immune response and increases mortality of H. diversicolor supertexta infected with V. parahaemolyticus.
Cheng
Winton
W
Department of Aquaculture, National Pingtung University of Science and Technology, Pingtung, Taiwan, 912, ROC.
Hsiao
I-Shan
IS
Chen
Jiann-Chu
JC
D000818:Animals; D006434:Hemocytes / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000378:metabolism; D009573:Nitrites / Q000633:toxicity*; D010587:Phagocytosis / Q000187:drug effects; D016897:Respiratory Burst / Q000187:drug effects; D012908:Snails / Q000187:drug effects* / Q000276:immunology* / Q000382:microbiology*; D013624:Taiwan; D013997:Time Factors; D014736:Vibrio parahaemolyticus / Q000472:pathogenicity*
D009573:Nitrites; D014442:Monophenol Monooxygenase