三角帆蚌钩介幼虫寄生胁迫对黄颡鱼耗氧率和排氨率的影响

Effect of infection stress by glochidia of Hyriopsis cumingii on respiratory metabolism in yellow catfish,Pelteobagrus fulvidraco

采用静水呼吸室法研究了三角帆蚌钩介幼虫寄生胁迫对黄颡鱼耗氧率和排氨率的影响,并统计分析了被寄生状态下黄颡鱼的成活率和钩介幼虫最适寄生量。结果显示:对照组、正常寄生组和重度寄生组的黄颡鱼在钩介幼虫完全脱落后的成活率分别为100%、93.3%和50%;寄生胁迫对黄颡鱼耗氧率未产生显著影响(P>0.05);钩介幼虫寄生胁迫使寄主鱼排氨率显著增加(P<0.05),钩介幼虫寄生数量与排氨率的增加存在正相关性,与寄主鱼死亡率呈正相关关系;呼吸代谢O∶N显著降低,寄生组(B、C组)分别为29.64、27.22,接近以蛋白质和脂肪功能的比值24,未寄生组(A组)O∶N未出现明显变化。

The triangle pearl mussel,Hyriopsis cumingii,has uninominal special life cycle,and the glochidia need to undergo a short parasitic life and intake of adequate nutrition from the host fish to ensure that they could complete juvenile metamorphosis. The hydrostatic breathing room method was applied to study effects of infection stress by glochidia of triangle pearl mussel on oxygen consumption rate and ammonia excretion rate in yellow catfish Pelteobagrus fulvidraco, then the survival rate and the appropriate number of glochidia parasitized were analyzed. The results showed survival rate in experimental groups of Pelteobagrus fulvidraco were 100%,93. 3% and 50. 0% after the glochidia falling completely; and there was no significant difference in the oxygen consumption rate of the host fish infected by glochidia（ P〉0.05）; the ammonia excretion rate was significantly increased and O/N ratio decreased（ P〈0.05）,and,there was a positive correlation between the quantity of glochidia and ammonia excretion rate,and positive with the mortality of host fish. So it could be concluded that： after being parasitized by the glochidia,a large number of cysts were induced to affect the respiratory system of host fish,thus hindering its use of oxygen.