为探明刺激隐核虫感染对褐菖生理机能的影响,研究分别用2500、5000、7500和10000幼虫/鱼的刺激隐核虫感染褐菖,并分别检测感染后24h、48h、72h 和96h各时间点血清中皮质醇(COR)、血糖(GLU)、总蛋白(TP)含量;肝脏中丙二醛(MDA)和维生素 C(VC)含量,超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活力;鳃和皮肤中溶菌酶(LZM)活力。结果显示,随着感染浓度的增加,血液中 COR 和 GLU 含量均出现不同程度的升高,其中2500、5000和7500幼虫/鱼组COR含量的最高值均出现在感染后第3天;而TP含量总体呈现逐步下降的趋势,尤其当感染浓度达到5000幼虫/鱼后, TP 含量的下降程度明显增加;肝脏中 MDA含量呈先降后升的变化趋势,其中24h、48h和72h 各点MDA含量的最大值均出现在10000幼虫/鱼组,最小值则集中出现于在2500和5000幼虫/鱼组;而VC含量则与MDA含量的趋势相反;SOD和CAT活力均出现不同程度的升高;鳃和皮肤 LZM 活力总体呈先上升后回落的变化趋势。综上可知,刺激隐核虫感染会对鱼体造成氧化胁迫和脂质过氧化反应,其严重程度与感染的虫细胞浓度相关。低浓度感染组的鱼所受胁迫较轻,在滋养体脱落后仍具有一定的自我修复能力;而高浓度感染组鱼免疫因子的释放受到抑制或出现紊乱,即便在虫体脱落后,其体质也很难恢复。
To investigate the effects of a Cryptocaryon irritans infection on the biochemical functions and immune re-sponses of the marbled rockfish Sebastiscus marmoratus, this study utilized C. at concentrations of 2,500, 5,000, 7,500, and 10,000 theronts/fish to infect marbled rockfish weighing (45±3) g. Within 96 hours after the infection we measured a variety of parameters at different time points, including (in the serum) cortisol (COR), glucose (GLU), total protein (TP) contens, (in the liver) the malondialdehyde (MDA) and vitamin C (VC) contents, the superoxide dismutase (SOD) and catalase (CAT) activities, and (in the gill and skin) the lysozyme (LZM) activities of the marbled rockfish. The re-sults showed that the serum COR and GLU contents of the marbled rockfish gradually increased along with the infection concentration and the lapse of time after the infection. However, the TP content decreased while infection concentration increased. Compared to the control, MDA contents in the liver decreased significantly in the 5 000 theronts/fish infec-tion group, then increased significantly and reached the maximum in the 10000 theronts/fish infection group. VC con-tents in the liver initially rose and then dropped. Compared to the control group, the SOD and CAT activities of the fish were significantly elevated. The LZM activities in the gill and skin initially increased and then decreased. In conclusion, C. irritans infection may result in adverse effects on the rockfish, probably through oxidative stress and lipid peroxida-tion. The physiological functions of the fish infected with low concentrations of C. irritans theronts could be effectively restored after the removal of trophont from the host; however the infection with high concentrations irreversibly im-paired the release of immune factors.