الفهرس 
1Pollution of the environment 6 1.2- Oreochromis niloticus (Nile tilapia) 7Only 14 pages are availabe for public view
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Abstract
The fish Nile tilapia Oreochromis niloticus collected from different
pollution stations along the River Nile to assess the insulin-like growth
factor-1 (IGF-1), antioxidant enzymes, and heavy metals. Moreover water
samples were collected from River Nile to evaluate levels of some
physicochemical parameters and heavy metals. The results showed that
the physicochemical concentrations of the water samples were:
temperature 16.3-36.5 C°, transparency 54.3-80.2 cm, electrical
conductivity 268-320μS/cm, pH 7.5-8.3, dissolved oxygen 7.3-11.2 mg/l,
biochemical oxygen demand 1.3-3.3 mg/l, chemical oxygen demand 6.3-
10.7 mg/l, and ionized ammonia 0.57-0.96 mg/l. Heavy metals namely
Fe, Mn, Cu, Zn, and Pb in water showed maximum value:
(5.8,0.51,0.350,0.230 and 0.90 mg/l) and (5.2, 0.42, 0.13, 0.47, and 0.27
mg/l) in summer and winter, respectively. The obtained results of the
same metals in fish muscle and gills of Nile tilapia were higher than that
found in water. The results of the present study further exhibited
increased activities of aspartate aminotransferase (AST) and alanine
aminotransferase (ALT), and levels of urea, uric acid, glucose, and
cholesterol in the blood of O. niloticus, and insulin-like growth factor-1
(IGF-1) levels were higher in fish collected from polluted sites ( iron and
steel factory at helwan, sugar cane factory at el-hawamdia, road el-farag,
and electricity station at shobra el-khima ). The activities of catalase
(CAT) and superoxide dismutase (SOD), and level of malondialdehyde
(MDA) showed significant increase (P<0.05) when compared to
reference station ( V ) EL-Qanater.
The results revealed a significant increase and decrease (P> 0.05) in the
chemical composition of O. niloticus muscle. The moisture, protein,
lipid, ash, carbohydrates and calorific values varied between
(80.10–80.15% , 80.33-80.38%), (17.01–17.11% , 17.15-17.36%),
(1.16–1.22% , 1.11-1.29%), (1.1–1.19% , 1.09-1.13%), (0.32–0.63% ,
0.10-0.32% ) and (80.7–81 kcal/100 g , 79.8-81.6 kcal/100 g) in summer
and winter, respectively.
The results of the present study exhibited increased activities of AST,
ALT and levels of urea and uric acid in the blood of O.niloticus fish
sample at site (I) which may be due to heavy metals in water.
Keywords:Nile tilapia, IGF-1, Antioxidant activity, Heavy metals,
Biochemical parameters