DNA damage and physiological responses in an Indian major carp Labeo rohita exposed to an antimicrobial agent triclosan

This study is aimed to evaluate the toxic effects of triclosan (TCS) in an Indian major carp Labeo rohita. The 96-h LC50 value of triclosan to L. rohita was found to be 0.39 mgL(-1). Fish were exposed to two sublethal concentrations (0.039 mg L-1, treatment I and 0.078 mg L-1, treatment II) of TCS for 35 days, and certain hematobiochemical, antioxidant, histopathological responses were measured. Compared to the control group, there was a significant (p < 0.05) decrease in the values and genotoxicity of hematological parameters such as hemoglobin (Hb), hematocrit (Hct), and erythrocyte (RBC) in TCS-exposed fish, but the values of leucocyte count (WBC), mean corpuscular volume (MCV), and mean corpuscular hemoglobin (MCH) were found to be increased. A biphasic response in mean corpuscular hemoglobin concentration (MCHC) value was observed during the study period (35 days). Significant (p < 0.05) alterations in plasma biochemical parameters (glucose and protein), electrolytes (Na+, K+, and Cl-), and transaminases (GOT and GPT) were observed in fish treated with TCS in both treatments. Gill Na+/K+-ATPase activity was found to be decreased in fish treated with TCS in both treatments. Enzymatic and nonenzymatic antioxidant index levels have also fluctuated in all the tissues (gill, liver, and kidney). The histological lesions were comparatively more severe in the gill than the liver and kidney. Comet assay showed DNA damage on exposure at two sublethal concentrations. The present results suggest that TCS is highly toxic to fish even at sublethal concentrations.