الفهرس 
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Abstract
The use of biomarkers has become an important tool for modern environmental assessment as they can help to predict pollutants involved in the monitoring program. Here we present data on bioaccumulation, biochemical and tissues bio-markers in Nile tilapia, Oreochromis niloticus as early warning indicators of pollution. Nile tilapia collected from contaminated aquatic habitats (Lake Qaroun and its neighboring fish farm), in comparison with fish from a non-polluted reference site.
Methods: Physico-chemical parameters i.e. electric conductivity, total hardness, total alkalinity, dissolved oxygen, nitrite and nitrate were determined in the studied sites. Heavy-metal concentrations (Fe, Mn, Zn, Cu and Cd) in water and tissue samples were recorded. Liver and kidney function tests with some blood parameters were measured in Nile tilapia. Oxidative stress biomarkers (MDA, GSH, GST and catalase), Endoplasmic Reticulum (ER) stress biomarker (Caspase-12) and Hypoxia related biomarker (VEGF) were determined in blood and tissue samples. Histopathological examination of liver, kidney, gills and muscles with SDS electrophoresis of serum and muscle proteins are used to study the effect of aquatic pollution on Nile tilapia from contaminated aquatic habitats.
Results: Water quality of samples collected from Qaroun fish farm and Lake Qaroun showed highly significant difference from reference site. Concentration of heavy metals in water samples from contaminated aquatic habitats was significantly higher than reference site. Bioaccumulation of either of the studied heavy metals in liver, kidneys, gills and muscles of the Nile tilapia; Oreochromis niloticus collected from Qaroun fish farm and Lake Qaroun was much higher than that of fish collected from reference site. The results showed significant increase in liver and kidney function tests in fish from polluted locations. A highly significant difference in stress (oxidative stress, ER stress and hypoxia) related biomarkers was recorded in fish from Qaroun fish farm and Lake Qaroun when compared to reference site. Histopathological alterations and evident damages were observed in liver, kidney, gill and muscle of Nile tilapia collected from Qaroun fish farm and Lake Qaroun compared with those from the reference site. The results of the present study revealed differences in the banding pattern of serum and muscle proteins of Nile tilapia collected from polluted sites compared to reference site.