Histopathological alterations in the liver and intestine of Nile tilapia Oreochromis niloticus exposed to long-term sublethal concentrations of cadmium chloride
Hossam, YOUNIS Elsayed 1, ** , ABDEL-WARITH Abdel-Wahab 1, 2 , AL-ASGAH Nasser 1, EBAID . 2015
Fingerlings of Nile tilapia Oreochromis niloticus were exposed to 1.68, 3.36, and 5.04 mg/L
cadmium (as CdCl 2 ), which represent 10%, 20%, and 30% of their previously determined 96-h LC 50 .
After exposure for 20 days, sections of the liver and intestine of treated fi sh were examined histologically.
Histopathological changes varied from slight to severe structural modifi cation, depending on the exposure
concentration. The hepatic tissues of fi sh exposed to 10% LC 50 showed markedly increased vacuolation
of the hepatocytes and coarse granulation of their cytoplasm. Abundant erythrocytic infi ltration among
the hepatocytes was observed in fi sh exposed to 20% LC 50 . In the intestinal tissues of fi sh exposed to all
doses, goblet cells proliferated and were greatly increased in size, the longitudinal muscularis mucosa was
disturbed and, in the crypts of the sub-mucosal layer, apoptosis increased, indicated by large numbers of
degenerated nuclei. Large numbers of infl ammatory cells and dilated blood vessels were observed in the
intestine of the group treated with 30% LC 50 .
