Antioxidant defenses and biochemical changes in the neotropical fish pacu, Piaractus mesopotamicus: responses to single and combined copper and hypercarbia exposure.
This study investigated the potentially detrimental effects of copper and elevated aquatic CO(2) (hypercarbia), alone or in combination, on pacu, Piaractus mesopotamicus. Fish were exposed for 48 h to control (no copper addition in normocarbia), to 400 μg Cu(2+)L(-1), to hypercarbic (1% CO(2); PCO(2) = 6.9 mm Hg) water and to 400 μg Cu(2+)L(-1) + hypercarbia. In liver the single factors caused an increase in lipid hydroperoxide concentration that was not observed when the factors were combined. Copper exposure elicited increased hepatic superoxide dismutase activity, irrespective of aquatic CO(2) level. On the other hand, the effects of copper on hepatic glutathione peroxidase activity were dependent on water CO(2) levels. The two stressors combined did not affect hepatic catalase activity. Hypercarbic water caused a decline in plasma glucose concentration, but this was not observed when hypercarbia was combined with copper exposure. Copper caused a decrease in branchial Na(+)/K(+)-ATPase activity that was independent of water CO(2) level. Copper caused an increase in branchial metallothionein concentration that was independent of water CO(2) level. Thus, branchial metallothionein and Na(+)/K(+)-ATPase were effective biomarkers of copper exposure that were not affected by water CO(2) level.
Brazilian Agricultural Research Corporation, EMBRAPA, Environment, Ministry of Agriculture, Livestock and Food Supply, Jaguariúna, SP, Brazil.
Fernanda Garcia
FG
Sampaio
Cheila de Lima
Cde L
Boijink
Laila Romagueira Bichara
LR
dos Santos
Eliane Tie
ET
Oba
Ana Lúcia
AL
Kalinin
Alfredo José Barreto
AJ
Luiz
Francisco Tadeu
FT
Rantin
D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D001774:Blood Chemical Analysis / Q000379:methods; D002245:Carbon Dioxide / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D060126:Characidae / Q000378:metabolism*; D003300:Copper / Q000633:toxicity*; D004781:Environmental Exposure / Q000032:analysis*; D005880:Gills / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008099:Liver / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D008668:Metallothionein / Q000378:metabolism; D010084:Oxidation-Reduction; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism; D013482:Superoxide Dismutase / Q000378:metabolism; D018675:Toxicity Tests / Q000379:methods; D014873:Water Pollutants / Q000633:toxicity
D000975:Antioxidants; D014873:Water Pollutants; D002245:Carbon Dioxide; D003300:Copper; D008668:Metallothionein; D002374:Catalase; D013482:Superoxide Dismutase; D000254:Sodium-Potassium-Exchanging ATPase