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Environmental Science and Pollution Research
springer
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Abstract: |
Methyl mercury chloride “MMC” (CH3ClHg) is an ubiquitous environmental toxicant that causes a variety of adverse effects. In
the present study, we investigated the effects of sub-chronic toxicity ofMMC on Nile tilapia (Oreochromis niloticus) through the
evaluation of growth performance and hematological, biochemical, and oxidative stress biomarkers. From 150 healthy fish, five
equally sized treatment groups were created: a control (CT) group fed with a basal diet and fourMMC treatment groups exposed
to 0.5, 1, 1.5, and 2 mg ofMMC per kg of basal diet for 60 days. MMC exposure significantly reduced the growth performance
and survival of O. niloticus and decreased red blood cell count and hemoglobin concentration. Treated fish exhibited normocytic
normochromic anemia in addition to leucopenia, lymphopenia, granulocytopenia, and monocytopenia. Moreover, MMC exposure
significantly affected liver function, including a reduction in the total protein levels while increasing cholesterol and
triglyceride levels. It also markedly increased the production of stress biomarkers such as glucose and cortisol levels.
Furthermore, MMC significantly elevated the levels of hepatic enzymes, induced tissue damage, and caused inflammation, as
indicated by the upregulation of mRNA expression of hepatic metallothionein. Finally, MMC exposure induced oxidative stress
by altering the antioxidant status of the liver and downregulating the mRNA expression of superoxide dismutase, glutathione
peroxidase, and glutathione S-reductase. In conclusion, MMC toxicity induced hematological and biochemical alterations,
leading to an enhanced state of oxidative stress in O. niloticus.
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