Studies on the effect of dimecron on the digestive system of a fresh water fish, Channa punctatus.

The effect of exposure to a sublethal concentration (0.32 mg/L) of Dimecron for 20 days on the digestive system of a fresh water teleost fish, Channa punctatus has been studied. The most conspicuous pathological changes in the liver were vacuolation of the cytoplasm of hepatocytes, enlargement of nuclei, rupture of the cell membrane, liver cord disarray, damage of connective tissue, infiltration of phagocytes and necrosis. The mucosa of stomach was ruptured and the gastric glands were degenerated. The mucosal epithelium of intestine and pyloric caeca was also degenerated. The mucus secreting goblet cells showed hyperactivity and the intestinal lumen was filled with mucus. No conspicuous changes were noted in the rectum except for hypersecretion of mucus. Histochemical tests revealed that alkaline phosphatase and glucose-6-phosphatase were inhibited by Dimecron treatment. However, acid phosphatase showed slight increase in activity. Biochemical tests for enzyme activity confirmed the histochemical findings. Alkaline phosphatase activity was significantly inhibited in liver and intestine. There was a slight elevation in the activity of acid phosphatase in the liver and pyloric caeca of exposed fish, but this was not statistically significant. The glucose-6-phosphatase activity was significantly inhibited in the liver, intestine and pyloric caeca.