Cellular biomarker responses of bagrid catfish, Chrysichthys nigrodigitatus in a contaminated coastal ecosystem
An assessment of the pollution status of Agboyi creek, a water body associated with various anthropogenic activities was carried out in order to determine responses induced in Catfishes, Chrysichthys nigrodigitatus inhabiting it. Cellular biomarkers of stress including the antioxidative stress enzyme, catalase (CAT), lipid peroxidation measured as thiobarbituric acid reactive substance (TBARS), as well as serum enzymes alanine aminotransferase (ALT) and Aspartate aminotransferase (AST) were evaluated in C. nigrodigitatus from Agboyi creek and compared to a control (non-polluted) water body, Epe Lagoon. The results of physicochemical assessments of both water bodies showed significant differences (P<0.05) with Agboyi creek having high levels of total suspended solids (TSS), phosphate as well as total dissolved solids (TDS) and heavy metal concentrations which exceeded National Environmental Regulations (NESREA) safe limits. The mean concentration (Mean ± SD) of TBARS in the liver of C. nigrodigitatus at Agboyi Creek (2455.43 ± 1440.0 nmol/mg protein) was about twice the levels at Epe Lagoon (1398.31 ± 1446.50 nmol/mg protein). Inhibition of CAT activity was observed in liver samples of catfishes at Agboyi Creek (48.17 ± 60.23 μmol/min/mg protein) compared to Epe Lagoon (87.97 ± 13.00 μmol/min/mg protein). The mean activities of ALT and AST were significantly higher (P<0.05) at Agboyi Creek (12.67 ± 15.04 and 151.67 ± 76.76 U/L) compared to Epe Lagoon (2.33 ± 0.52 and 6.00 ± 3.46 U/L). The present study shows altered biochemical conditions in fishes sampled in the water body impacted by anthropogenic contaminants and suggest that those parameters could be used as reliable biomarkers of contaminant exposure to fish.
Keywords: Biomonitoring, water pollution, oxidative stress, fish health.