镉暴露对鲢幼鱼游泳行为影响的研究

为了探讨水体镉(Cd)污染对鱼类的生态毒理效应,在实验室条件下,测定了不同浓度Cd(0、0.36、0.73、1.09和1.46 mg/L)暴露对鲢(Hypophthalmichthys molitrix)幼鱼半致死浓度、组织(肝、鳃、肌肉)Cd累积量、相对临界游泳速度(Ucrit)、以及耗氧率(MO_2)的影响。结果显示:Cd暴露导致重金属在幼鱼组织中累积,与对照组比较,Cd在鳃和肌肉中累积量差异不显著;肝脏中累积量差异显著,暴露浓度为0.73 mg/L时肝脏中镉累积量最高。鲢幼鱼相对临界游泳速度随着Cd暴露增加显著降低,浓度为1.46 mg/L时Ucrit为对照组的69.75%。临界游泳速度与鳃和肌肉组织中镉累积量呈显著负相关,相关系数分别为-0.96(P=0.01)和-0.90(P=0.04)。Cd暴露导致鲢幼鱼耗氧代谢范围增加,暴露浓度为0.73 mg/L时耗氧代谢范围较对照组增加了19.32%。低浓度Cd暴露导致鳃和肌肉损伤,并引起鲢幼鱼游泳过程中耗氧代谢效率降低,有氧运动能力和游泳能力下降。

Swimming behavior of juvenile silver carp (Hypophthalmichthys molitrix) exposed to cadmium

In this investigation, the eco-toxicological effects of cadmium on the swimming performances of juvenile silver carp ( Hypophthalmichthys molitrix) were measured. Cadmium concentrations were measured in tissues ( gill, liver and muscle) . The relative critical swimming speed ( Ucrit ) , as well as oxygen metabolic rate ( MO2 ) range were measured in juvenile silver carp after a 96 h exposure to a range of cadmium concentrations (0, 0. 36, 0. 73, 1. 09 and 1. 46 mg/L). The results showed that cadmium exposure had significant effects on the cadmium concentrations in tissues, especially, in the liver (F=4. 32, P=0. 038). Besides, cadmium exposure had significant effects on the Ucrit and MO2 range. The Ucrit was 30. 25% of the control after 96 h exposure to1. 46 mg/L cadmium. The correlation coefficients of critical swim-ming speed and cadmium accumulation in gill and muscle tissue were negative, -0. 96 (P=0. 01) and 0. 90 (P=0. 04) respectively. The metabolic range increased with the increasing of cadmium concentration. At 1. 46 mg/L of cadmium ex-posure, the metabolic range increased by 19. 32% than that of the control. The results indicated that cadmium exposure
would have significant effects on swimming capabilities and the metabolic rate of juvenile silver carp. Cadmium has inhibi-tory effect on juvenile silver carp behavior, and low Cd concentrations exposure resulted in gill and muscle damage, and caused a decrease in oxygen metabolic efficiency, aerobic capacity and swimming ability of juvenile silver carp.