Response of liver and gills of Mystus gulioto the heavy metal pollutants and metacercarian infection

Mystus gulio collected from the polluted waters of Veli lake in the Thiruvananthapuram district of Kerala, India was subjected to histopathological observations to study the effect of the pollutants on the tissue of the fishes. The epithelial layer of the secondary lamellae was lifted and detached from the underlying tissue, and was also seen in a degenerative form. The hepatocytes have lost their shape and regular arrangement, and was seen accumulated in a syncitial mass. Pycnotic nuclei, enlargement of nuclei and condensation of nuclear material were observed all through. Brownish pigments were scattered throughout the tissue which shows the possibility of accumulation of heavy metals. Inflammatory reaction of the liver against a metacercarian cyst was also demonstrated.