Laboratório de Ecofisiologia Animal - Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, Km 380. C.P. 10011, CEP: 86051-970, Londrina, Paraná, Brazil.
Laboratório de Ecofisiologia Animal - Departamento de Ciências Fisiológicas, Universidade Estadual de Londrina, Rodovia Celso Garcia Cid, Km 380. C.P. 10011, CEP: 86051-970, Londrina, Paraná, Brazil.
Aquat Toxicol. 2022 Nov;252:106315. doi: 10.1016/j.aquatox.2022.106315. Epub 2022 Sep 27.
Copper waterborne toxicity is well understood in aquatic organisms. However, the dietary copper effects are much less known, especially in tropical fish. The toxicity of copper via the trophic route could be influenced by the composition of the food, and diets naturally impregnated with copper seem to have greater toxicity at lower concentrations than artificially impregnated ones. Thus, our objective was to investigate the effects of copper on juveniles of the Neotropical fish Hoplias malabaricus fed on live prey (Astyanax altiparanae) previously exposed to the metal (20 µg L ) for 96 h. The prey fish were given to H. malabaricus every 96 h, totaling 10 doses at the end of the experiment. Thus, after 40 days fish were killed and tissues were sampled. Blood showed to be the only tissue in which copper accumulated. Anemia was found and there was damage to the DNA of erythrocytes. Furthermore, ionic imbalances were observed in plasma. There was an increase in the concentration of Na and Cl and a decrease in Ca, which were associated with increased copper uptake in the gastrointestinal tract of fish fed on copper exposed prey. All the antioxidant enzymes evaluated in the gills showed decreased activity compared to the control group. Copper seems to have interfered in the energy metabolism of H. malabaricus, since a lower condition factor and feed conversion efficiency rate were observed in fish fed with copper diet. The present study confirms the trophic route as an important copper toxicity pathway for H. malabaricus and reinforces the idea that metal toxicity can be increased when it is naturally impregnated in the prey tissues, even if the prey has been exposed to the metal only for a short period of time.
铜的水生毒性在水生生物中已得到充分认识。然而，铜的膳食效应却知之甚少，尤其是在热带鱼类中。通过食物链摄入铜的毒性可能会受到食物组成的影响，并且天然浸渍铜的食物似乎比人工浸渍的食物在较低浓度下毒性更大。因此，我们的目的是研究铜对摄食活饵（Astyanax altiparanae）的新热带鱼类Hoplias malabaricus 幼鱼的影响，这些活饵之前曾暴露于金属（20 µg L-1）中 96 h。每隔 96 h 给 H. malabaricus 投喂一次活饵，实验结束时总共投喂 10 次。因此，在 40 天后处死鱼类并采集组织样本。结果显示，血液是唯一积累铜的组织。研究发现鱼类出现贫血现象，并且红细胞的 DNA 受到损伤。此外，还观察到血浆离子失衡。暴露于铜的饵料会导致鱼体胃肠道对铜的吸收增加，进而导致血液中 Na 和 Cl 浓度升高，Ca 浓度降低。与对照组相比，鳃中所有评估的抗氧化酶活性均降低。铜似乎干扰了 H. malabaricus 的能量代谢，因为投喂铜饲料的鱼的体况系数和饲料转化率较低。本研究证实了食物链是 H. malabaricus 铜毒性的重要途径，并进一步证实了当金属天然浸渍在猎物组织中时，即使猎物只暴露于金属很短的时间，金属毒性也可能增加。
