The present study investigated the effects of chronic exposure to a sublethal concentration (20 mg/L) of the inorganic fertilizer ammonium chloride for 30 days on the snakehead fish Channa punctatus. Histopathological alterations were observed in several vital organs of the treated fish. Significant pathological changes were evident in the gills, liver, intestine, and kidney compared to the control group. The gills of ammonium chloride–exposed fish exhibited lamellar fusion, deterioration of secondary lamellae, haemorrhage, and destruction of gill arches. The liver showed marked pathological changes, including hyperaemia, vacuolar degeneration, necrosis, and mononuclear cell infiltration in the portal regions. In the intestine, distinct alterations such as hydropic degeneration, necrosis, desquamation of epithelial cells at the apex of the villi, and mononuclear cell infiltration in the lamina propria were observed. The kidney of treated fish revealed cellular shrinkage in the proximal and distal tubules, nuclear pyknosis, and vacuolar degenerative changes in the tubular epithelium. The findings of the present investigation clearly demonstrate that chronic exposure to ammonium chloride induces severe histopathological damage and dysfunction in vital organs of C. punctatus. The study suggests that contamination of fish culture pond water with ammonium chloride fertilizer should be strictly avoided to ensure sustainable fish production and aquatic health.
Sameen Anjum (Thu,) studied this question.