Biochemical properties and heavy metal analysis of a commercial fish Opisthopterus tardoore

Abstract

Aim: The study was designed to evaluate various biochemical parameters, protein expression, antioxidant enzymes and heavy metals by testing an edible fish Opisthopterus tardoore. Methodology: The experimental fish were collected from five major fish markets of Bhubaneswar, India and distribution of carbohydrate, lipid and protein content were assessed in muscle tissues. To enhance the understanding of molecular mechanism, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of crude proteins was conducted. Catalase (CAT) and guaiacol peroxidase (GPX) activities were determined both spectrophotometrically and by native gel electrophoresis. For heavy metal analysis, three toxic elements viz.,chromium, cadmium and lead were examined by atomic absorption spectrophotometer. Results: The muscle tissues showed variation in the concentrations of carbohydrate (0.17 ± 0.02 to 0.28 ± 0.04 % f.wt.), lipid (3.48 ± 0.27 to 6.62 ± 0.44 % d. wt.) and protein (1.56 ± 0.11 to 2.92 ± 0.16 % f. wt.) with respect to the markets from where fish samples were collected. The protein profiling study revealed the disappearance as well as de novo synthesis of some proteins. The activities of CAT and GPX were determined for establishing a possible bioindicator of metal toxicity in fish. A rapid disturbance in their enzymatic actions was noticed which was also confirmed through native polyacrylamide gel electrophoresis with respect to fish samples. The heavy metals analysis manifested a varying level of accumulation of Cr whereas Pb and Cd were found below the detection limits. Interpretation: The biochemical disturbances and accumulation of Cr in muscle tissues of O. tardoore reflect the pollution status of nearby coastal areas of the Bay of Bengal, Odisha. Key words: Biochemical analysis, Chromium toxicity, Guaiacol peroxidase, Opisthopterus tardoore, Protein expression