Assessment of Kidney Function Biomarkers in Mystus seenghala Following Malathion Exposure

Abstract

The increased reliance on organophosphate pesticide use in agriculture has created concerns regarding how these products may affect freshwater ecosystems. One example would be malathion, as it is one of the most widely used organophosphate insecticides and has high-levels of toxicity toward aquatic organisms (especially fishes). The goal of this study was to determine sub-lethal effects of malathion on the function of kidney biomarker function in the freshwater catfish (Mystus seenghala). The study used healthy fish that were held in acclimation conditions within a laboratory prior to treatment, so they would understand the conditions of being held under normal circumstances. All of the fish used in this project were treated with malathion at 1/10th (one-tenth) of their respective 96-hour LC₅₀ concentration (malathion), for a total of 6 durations (1, 7, 15, 30, 45 and 60 days). Serum samples of the fish were analyzed for levels of urea, creatinine and ammonium (as dissolved) in accordance with standard biochemical methods. Compared with the control, the results of the trial showed the three markers were significantly elevated, with a duration-dependent effect on all markers over time. The elevation in urea and creatinine was indicative of glomerular function impairment, while the increase in dissolved ammonia indicated a disruption of nitrogen metabolism and poor elimination efficiency. Although there was no evidence of mortality, the trend (progressive) of increased biochemical values supports nephrotoxicity from chronic exposure. These results indicate that kidney biomarkers are sensitive early indicators of pesticide stress on freshwater fish; therefore, ongoing kidney biomarkers biomonitoring is needed to protect freshwater fish and promote/intervene in the ecological balance.