Effect of triclosan (TCS) on the protein content and associated histological changes on tilapia, Oreochromis mossambicus (Peters, 1852)

Triclosan is a chlorinated phenolic antimicrobial agent having a wide application in commercial and healthcare products. The toxic effects of the emerging pollutant, triclosan (TCS), on behavior, protein content, and associated histological alterations in the muscle tissue of the freshwater fish Oreochromis mossambicus were studied. Healthy fishes were exposed to five different acute concentrations of TCS, viz., 0.131, 0.262, 0.523, 1.046, and 2.092 ppm for a period of 96 h. The 96-h LC50 of TCS for O. mossambicus was determined as 0.715 ppm using probit analysis. The fishes were also chronically exposed to the five different concentrations of TCS based on LC50 to study the toxic effects of long-term exposure. The protein content of the fish muscle gradually decreased with an increase in the concentration of TCS. Further, the histological alterations such as splitting of myotomes, vacuolar degeneration, degenerated myotomes, multifocal degeneration of myocytes, degeneration of myoepithelium, myolysis, melanomacrophage in the dermis, vacuolation in the epidermis, atrophy of myotomes, and necrosis were observed during the acute and chronic exposure of fishes to TCS. The study revealed that TCS can affect the aquatic organisms even at a minimum concentration of 0.715 ppm causing changes in the behavior and biochemical constituents of tilapia.