Effects of exposure to multiple trace metals on biochemical, histological and ultrastructural features of gills of a freshwater fish, Channa punctata Bloch

Abstract The trace metals are frequently encountered as mixtures of essential and non-essential elements. Therefore, evaluation of their toxic effects individually does not offer a realistic estimate of their impact on biological processes. We studied effects of a mixture of four essential and toxic metals (Cu, Cd, Fe and Ni) on biochemical and morphological characteristics of the gills of a biomarker freshwater fish Channa punctata (Bloch) using environmentally relevant concentrations. Fish were exposed to metal mixture through tank water for 7, 15 and 30 days. Biochemical studies as well as light microscopy (LM) and scanning electron microscopy (SEM) revealed significant metal exposure-induced alterations in gills. Besides ultastructural changes, activities of antioxidant enzymes such catalase (CAT), glutathione S -transferase (GST) and superoxide dismutase (SOD) were significantly altered in the gills of exposed fish. The reduced glutathione (GSH) was significantly ( p p