This study focused on two areas (Abu-Zaabal and El-Tal El-Kabir) of the Ismailia canal. The samples represented the effect of the factories' effluent discharge onto the canal. Physical characteristics (water temperature and pH) and chemical characteristics (total hardness, dissolved oxygen, biological oxygen demand and chemical oxygen demand) were measured to identify the water quality in the two areas of the Ismailia canal. These measurements showed slight variations between the two stations. Additionally, the histological and histochemical analyses in the liver of Bagrus bayad fish samples were done. Histological studies of liver showed more severe degeneration in the fish samples of El-Tal El-Kabir station. Histochemical studies on protein and glycogen contents in the liver of B. bayad showed a progressive decrease in their staining intensity to bromophenol blue and periodic acid Schiff at two stations. This study, therefore, concludes that Ismailia canal water (Abu-Zaabal and El-Tall El-Kabir) stations create metabolic crisis and impairment in fish liver. The depletion in the levels of protein and glycogen points leads to the exhaustion of cell energy that is of high demand for fish during stressful conditions. Therefore, it is imperative for the authorities concerned to ensure that treated effluent discharge comply with acceptable standards to save our environment from destruction.

T he effect of the heavy metals Cu, Zn, Cd and Pb on the gill and liver tissues of the Nile tilapia, Oreochromis niloticus was examined in the laboratory. One hundred and fifty adult fish were divided into five groups (control, copper, zinc, cadmium and lead) each group containing 30 fish. They were continuously exposed to sub-lethal concentration of each metal (lmg/L) for a period of 10 days. From each group, the gills and liver of six fish were removed after 10 days and the remaining fish were transferred to tap water for : a recovery period (21days). The tissue samples of gills and liver of both treated and recovery fish were dissected for histological examination. The results showed that the extent of distortion of the gills and liver was more pronounced in the fish group that were exposed to Cd&Pb.

No abstract

The Nile River islands are recognized as the most productive lands in Egypt. Although, these islands are vulnerable to several natural and man-made crises. The present study was aimed to evaluate the consequences of different anthropogenic activities on the heavy metals load and histological alterations in O. niloticus and S. galilaeus collected from four different Nile River islands along the Great Cairo sector (Egypt), and the possible health risks for human consumers. Metals were accumulated in both fish muscles in the following order: Fe > Zn > Cu > Mn > Pb. S. galilaeus was recorded higher metal pollution index than O. niloticus, while El-Warrak Island was documented the highest MPI and hazard quotient among all sampling sites. All sampled tissues were recorded histopathological lesions in both fish. The present study may be considered as an early alert for habitual consumers, particularly at high consumption rates of some fish species.

Fish is a good indicator for monitoring of heavy metals risks. The present study was conducted to evaluate the effects of Chlorella vulgaris and Spirulina platensis dietary supplementation on Oreochromis niloticus growth under normal conditions. Additionally, evaluation of their effects on the growth performance, growth-related genes expression and antioxidant enzymes of O. niloticus exposed to a mixture of heavy metals. The results showed that the highest growth performance of O. niloticus was recorded in the groups supplemented with 10 and 15% of S. platensis compared to C. vulgaris and control groups. The expression of ghrelin, leptin and insulin-like growth factor genes (IGF-1) were improved in fish that fed on 10% and 15% of S. platensis more than C. vulgaris against the toxic impact of heavy metals. 15% of C. vulgaris improved the activity of catalase (CAT), while the activity of superoxide dismutases (SOD) was improved at 10% of both C. vulgaris and S. platensis. C. vulgaris and S. platensis increased glutathione peroxidase (GPx) activity compared to the normality. Our results concluded that S. platensis can effectively provide a protection in terms of growth-related genes expression in O. niloticus. Further, both C. vulgaris and S. platensis modulated heavy metals-induced oxidative stress.