Effect of subleathal concentrtion of imidacloprid on the histology of heart, liver and kidney in Labeo rohitr

Randomly selected 500 fingerlings of Labeo rohita were collected from fish seed hatchery Muzaffar Garh. Six groups of 40 fish each were exposed to subleathal concentration of Imidacloprid [120 mg L[-1]] under short-term [2, 4 and 8 days] and long term [16, 32 and 64 days] conditions to assess the effect of this most extensively used insecticide on the heart, liver and kidney of economically most important fresh water fish, L. rohita, in Pakistan. Separate control groups were used for each Imidacloprid treatment. No drastic histopathological changes were observed in heart structure following short and long term treatment with Imidacloprid. Exposure of liver to Imidacloprid resulted in severe degenerative changes, which were directly related to exposure time. Wrinkling of hepatocyte cell membrane, hepatocyte necrosis and degeneration, dislocation of nucleus, dilation of blood sinusoid and pycnosis of hepatic nuclei were the visible changes in liver histology in various experimental treatments. Comparison of treated and untreated kidney of L. rohita revealed wide Bowman's space, renal tubular lumen enlargement, necrosis and inflammation of cells. Our results are the pioneer report indicating that imidacloprid can act as strong toxic agent for L. rohita