The effects of heavy metals on growth, intermediary metabolism and enzyme activities were investigated in yellow perch (Perca flavescens), sampled in summer and fall from lakes situated along a contamination gradient of Cd, Zn and Cu in the mining region of Rouyn-Noranda, Québec. An exposure-dependent decrease in condition factor was observed in both seasons. Liver glycogen and triglyceride reserves were higher in summer than in fall in fish from the reference lake, while the seasonal pattern was different in fish from the contaminated lakes. Plasma free fatty acids (FFA) levels were also influenced by season and contamination. Activities of malic enzyme (ME) and glucose 6-phosphate dehydrogenase (G6PDH) in the liver were higher in the summer than in the fall in reference lakes whereas no seasonal variations were detected in fish from contaminated lakes. Activities of pyruvate kinase (PyK), aspartate transaminase (AST), phosphoenolpyruvate carboxykinase (PEPCK) and malate dehydrogenase (MDH), were higher in fish from contaminated lakes in fall but not in summer. Chronic exposure of yellow perch to sublethal levels of heavy metals impairs growth and alters the seasonal cycling of liver glycogen and triglycerides as well as the activities of metabolic enzymes.
Bibliographical noteFunding Information:
The study was funded by Canadian Network of Toxicology Centers (Reproduction and Endocrine Toxicology Program). Metals were measured by S. Premont at INRS-Eau, Université de Québec; the analyses were funded by MITE-RN (Metals in the Environment-Research Network). We thank A. Lacroix, G. Sherwood, J. Dorval, A. Gravel and J. Doire, for help in the field, V. Leblond for help in the laboratory.
- Intermediary metabolism
- Yellow perch