铜暴露对草鱼幼鱼代谢行为的影响

Effect of copper exposure on metabolism behavior of juvenile grass carp(Ctenopharyngodon idella)

为了探讨水体中铜污染对鱼的生态毒理效应和游泳能力的影响,在实验室条件下,测定了铜暴露草鱼(Ctenopharyngodon idella)幼鱼半致死浓度、不同浓度铜暴露(0、0.025、0.050、0.075、0.10 mg·L^(-1))96 h后组织(肝、鳃、肌肉)铜累积量、相对临界游泳速度(U_(crit))以及耗氧率(MO_2)。结果表明:与对照组比较,铜暴露对组织(肝、鳃、肌肉)铜累积量无显著影响(P>0.05),铜对草鱼幼鱼的安全浓度为0.008 mg·L^(-1)。铜暴露草鱼幼鱼相对临界游泳速度受抑制显著(P<0.05),不同浓度暴露后U_(crit)分别较对照组下降了18.4%、21.8%、33.8%和38.1%。随着游泳速度的增加,其速度-代谢率关系为MO_2=a+b×U^c,随着暴露浓度增加,速度参数c值增加,不同浓度铜暴露后c分别比对照组增加了37.78%、33.33%、56.67%和61.11%,表明游泳能量利用率下降。铜暴露导致草鱼幼鱼有氧代谢范围增加,0.1 mg Cu·L^(-1)时有氧代谢范围比对照组增加了37.48%。铜暴露对草鱼幼鱼的游泳能力以及氧代谢行为产生影响,尤其是导致游泳效率降低、抑制游泳能力。

In this investigation, the eco-toxicological effects of copper on the swimming capability of juvenile grass carp（Ctenopharyngodon idella） were measured. Copper concentrations were measured in the gill, liver and muscle tissues of juvenile grass carp after a 96 h exposure to a range of copper concentrations; 0, 0.025, 0.050, 0.075 mg·L^-1 and 0.10 mg·L^-1. Relative critical swimming speed（Ucrit） and metabolic rate（MO2） range were also measured after exposure. While the exposure did not significantly affect tissue concentrations（P〉0.05）, it did significantly affect Ucrit and MO2 range（P〈0.05）. The safe concentration for juvenile grass carp was 0.008 mg Cu·L^-1. Compared to the control group, Ucrit decreased by 18.4%, 21.8%, 33.8% and 38.1% after 96 h exposure to 0.025, 0.05, 0.075 mg Cu·L^-1 and 0.10 mg Cu·L^-1, respectively. The oxygen consumption rate increased exponentially with swimming speed; MO2=a＋b×U^c. The speed parameter, c, increased with copper concentration by 37.78%, 33.33%, 56.67% and 61.11%, indicating a decrease in swimming efficiency. MO2 range increased by 37.48% after exposure to 0.10 mg Cu·L^-1 copper. Exposure to copper polluted environment significantly affects the metabolism and swimming performance of juvenile grass carp, especially resulted in the decrease of swimming efficiency, inhibited swimming ability.