Remediation of toxic effect of Mercuric Chloride on the Nile Tilapia, Oreochromis niloticus using Selenium

Abstract

The present results showed that heavy metals (HgCl 2 ) have affected the biological parameters of Oreochromis niloticus. These effects depended on the duration of the exposure and the concentration of the heavy metal used. The effect of various doses level of HgCl 2 on the erythrocyte count (Red blood cells) decreased under the effect of the high doses of HgCl 2 (0.08 mg/l or more). A significance difference was recorded in comparison with the control fish (p<0.05).The total white blood cells counts significantly increased as the concentration of HgCl 2 increase when compared to the control fish. In contrast, hemoglobin (Hb) levels significantly (p<0.05) decreased after the fish exposed to high level doses of HgCl 2 . Addition of selenium (Na 2 SeO 3 ) at doses of 1.0 and 2.0 mg/kg to fish food for a period of 20 days of treatment with HgCl 2 improved blood constituent. Treated gills with high doses of HgCl 2 showed alteration on both of primary and secondary lamellae and an increase in the mucous secretion when compared with the control tissue. No abnormalities occurred in the liver of control fish. The main alterations in the liver of fish were observed after treatment with high doses level of HgCl 2 (0.06-0.08mg/l). The hepatocytes were hypertrophied and the nuclei showed necrosis.

Toxic Effects of Mercuric Chloride (HgCl2) on the Common Carp (Cyprinus carpio) Larvae and Recovery Using Selenium and Vitamins

“…Among the aquatic fauna, fish are the most sensitive group for heavy metal (El-Gamal 2002; El-Mattary et al, 2019). Moreover, mercuric chloride (HgCl 2 ) is considered one of the most dangerous heavy metals in the aquatic environment (Asefi & Zamani, 2015;El Mattary et al, 2019). Exposure to a high level of inorganic mercuric chloride causes a permanent damage to the kidney and brain of fish…”