低氧胁迫对九孔鲍免疫防御因子的影响

为了解低氧胁迫条件下九孔鲍免疫防御因子的变化及机体抗病力变化, 将九孔鲍置于不同的溶解氧环境中, 观测相关免疫因子变化。结果显示, 在水温为(22.1?1.3) oC, 盐度为30.72?0.54, pH值为8.20?0.14的海水环境中, 溶解氧含量由(7.49?0.14) mg/L下调至(2.53?0.16) mg/L后120 h内, 平均体质量为(14.25±2.21) g的九孔鲍未见死亡, 而每只鲍注射5.0?10⁵ CFU 副溶血弧菌后120 h内实验鲍的累计死亡率高达91.11%?7.70%, 比对照组(11.11%?3.83%)累计死亡率高出80%, 血淋巴抑菌清除率下降至?(3 340.47%?298.57%), 显而易见, 低氧胁迫使得九孔鲍拮抗副溶血弧菌感染的抵抗力显著下降。低氧(2.53?0.16) mg/L胁迫下, 九孔鲍血淋巴细胞数量(THC)下降30.62%?4.87%、血淋巴细胞吞噬率下降62.77%?5.79%、呼吸爆发产生的超氧阴离子数量下降22.21%?5.89%。低氧胁迫下九孔鲍血淋巴细胞内MPO活性上升(9.63%?7.59%)~(22.90%?13.73%)、CAT活性提高(7.68%?6.83%)~(56.28%?13.96%), 反映出低氧胁迫下九孔鲍体内应激反应产生的物质氧化加剧, 血淋巴细胞内产生大量的活性氧自由基。溶解氧含量由(7.49?0.14) mg/L下调至(4.51?0.12) mg/L后九孔鲍已明显处于低氧胁迫和应激反应状态, 120 h内的累计死亡率达到37.78%?3.85%, 血淋巴抑菌率下降至883.56%?123.22%; THC、血淋巴细胞吞噬率、呼吸爆发产生的超氧阴离子O₂^- 数量等最大降幅分别达到12.51%?6.59%、21.90%?15.84%、12.93%?5.74%; MPO活性在原有水平的?(10.61%?4.20%)~(7.13%?6.45%)之间波动, CAT活性在?(5.17%?18.08%)~(16.26%?10.85%)之间变化。

Effect of hypoxia on the immune response of the abalone Haliotis diversico-lor supertexta and its susceptibility to pathogen Vibrio parahaemolyticus.

The abalone Haliotis diversicolor supertexta is the most important aquatic species in many marine farms in China. For the purpose of qualitative observation on the variation of immune defense and natural resistance of animals, the abalones were put into waters with different dissolved oxygen and some immune effectors involved in defense were detected. In this paper the immune response of the abalone and susceptibility to pathogen Vibrio parahaemolyticus under hypoxia stress condition were described. The abalones with an average body weight (14.25±2.21) g could tolerate 120 hours for exposure to a hypoxic condition when dissolved oxygen was reduced from (7.49?0.14) mg/L to( 2.53?0.16) mg/L without onset mortality occured at a water temperature (22.1 ?1.3) °C, and a salinity level of 30.72?0.54, and pH 8.20?0.14, but they suffered 91.11%?7.70% cumulative mortality rate which was 80% higher than the control animals due to being chal-lenged with V. parahaemolyticus at a dose of 5.0?10⁵ cells per abalone, and a clearance efficiency in the haemolymph of H. diversicolor supertexta decreased to -(3 340.47% ? 298.57)% inhibition rate. Obviously, the resistance of the abalones to V. parahaemolyticus infection decreaced and the susceptivity inceassed correspondingly under the hypoxic stress above, in which the total haemocytes counts (THC) and percentage of phagocytosis and the amount of superoxide anion (O₂^- ) produced by respiratory burst decreased by 30.62%?4.87%, 62.77%?5.79%, and 22.21%?5.89% respectively. That intracellular MPO activity and CAT activity went up from 9.63%?7.59% to 22.90%? 13.73% and 7.68?6.83% to 56.28%?13.96% respectively while dissolved oxygen reduced from (7.49? 0.14) mg/L to (2.53?0.16) mg/L suggests that the intracellular oxidation introduced by hypoxic stress response intensified and there must be much more oxyradicals. The trial abalones of H. diversicolor supertexta possessed a cumulative mortality rate of 37.78?3.85% and a haemolymph inhibition rate of ?(883.56%?123.22)%, and the maximal downtrends of 12.51%?6.59%, 21.90%?15.84%, 12.93%?5.74)% in THC and percentage of phagocytosis and the amount of O2- production respectively, and a variation of MPO activity ranges from ?(10.61%?4.20%) to 7.13%?6.45% and CAT activity from ?(5.17%?18.08%) to 16.26%?10.85% while not only dissolved oxygen went down from (7.49?0.14) mg/L to (4.51?0.12) mg/L but also infection with V. parahaemolyticus occurred due to the obvious hypoxic stress.