Effect of nitrite on interaction between the giant freshwater prawn Macrobrachium rosenbergii and its pathogen Lactococcus garvieae

Diseases of Aquatic Organisms

Chun-Hung Liu¹  Winton Cheng¹  Jiann-Chu Chen¹ 

关键词: Macrobrachium rosenbergii;    Lactococcus garvieae;    Nitrite;    Challenge;    Virulence;    Hemocyte count;    Phenoloxidase activity;    Superoxide anion;   

DOI  :  10.3354/dao050189

学科分类：生物科学（综合）

来源: Inter-Research

【 摘 要 】

ABSTRACT: Addition of nitrite-N at 1.5 mg l^-1 in tryptic soy broth (TSB) significantly (p < 0.05) decreased the growth rate of the bacterial pathogen Lactococcus garvieae and significantly (p < 0.05) reduced mortality compared tozero nitrite controls when injected into giant freshwater prawns Macrobrachium rosenbergii at 5 x 10⁵ colony-forming units (CFU) per prawn. In other experiments, whereby prawns were injected with TSB-grownL. garvieae (5 x 10⁵ CFU prawn^-1) and then held in water containing nitrite-N, mortality at 72 h post-injection was significantly (p < 0.05) higher for prawns held in water containing 1.68 mgl^-1 nitrite than at lower concentrations. Prawns exposed to different concentrations of nitrite-N were examined for THC (total hemocyte count), phenoloxidase activity, respiratory burst, phagocytic activity and bacterial clearance efficiency.No significant differences in THC and phenoloxidase activity were observed among treatments. With prawns exposed to nitrite-N for 168 h (7 d) at 1.59 mg l^-1, phagocytic activity and clearance efficiency decreased, while at 1.15 mgl^-1 or more, respiratory burst increased, generating the superoxide anion at levels considered cytoxic to the host. We conclude that nitrite-N at 1.68 mg l^-1 causes depression in the immune response and increased mortality in M.rosenbergii infected with L. garvieae.

【 授权许可】

Unknown