Histopathological alterations of mercuric chloride toxicity in marine fish (Acanthopagrus latus)

The present study was conducted to understand the mechanisms of mercury toxicity in marine yellowfin seabream, Achanthopagrus latus fish. The histopathological effects of mercuric chloride exposure (10, 20, 40, 80 μg/L), for 3 weeks were studied. Samples of gills, liver, intestine and kidneys were studied by light microscopy. The gill at all doses of HgCl₂ showed desquamation, aneurism in secondary lamellae, lifting of the lamellar epithelium, oedema, epithelial hyperplasia and fusion of the secondary lamellae. Degenerative changes in hepatocytes, aggregation of macrophages and focal necrosis were found in the liver in dose dependent manner. Lesions in the kidney were characterized by degeneration in the epithelial cells of renal tubules, dilation of glomerular capillaries, hypertrophy of tuber epithelial cells, narrowing of tubular lumen, and hyaline degeneration. Focal degeneration of villi with swollen tips, increased goblet cells activity, leukocytic infiltration and mast cells aggregation were observed in intestinal folds.