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) is a unique, diverse group of enzymes that catalyze the oxidation of organic pollutants such as polycyclic hydrocarbons (PAHs). Both levels of cyp1a expression in Oreochromis aureus organs and the accumulation of PAHs in water were determined in five different locations of Lake Manzala; namely, El-Inaniya, El-Serw, El-Temsah, El-Gamil, and El-Bashtir during December 2011. The area of Al-Qanater was included as a reference site from the River Nile. The cyp1a gene was highly expressed in the liver of all fish populations followed by gill, testis, ovary and muscle. The liver and gonads of the fish population in the El-Gamil location exhibited the greatest cyp1a gene expression, while the gills and muscles in the El-Serw fish population were the highest in the expression pattern among Lake Manzala regions. A higher accumulation profile of PAHs in water was found in the El-Gamil location followed by El-Serw, El-Bashtir, El-Inaniya and El-Temsah. The correlation between PAHs and cyp1a expression of fish organs showed a significant positive correlation. The highest positive correlation was observed between the gill and liver based on the expression of cyp1a. The obtained cDNA of the cyp1a gene from O. aureus was 569 base pairs, and it exhibited 86.8% of the identity with cyp1a of O. niloticus. The phylogenetic tree of cyp1 family genes showed a closer relationship between cyp1a and cyp1d subfamily compared to cyp1b or cyp1c subfamily members. The results showed the sensitivity of cyp1a expression in fish as a biomarker for PAHs concentrations in the regions of Lake Manzala.]]>
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0.05) was found when compared to watermeal cultivated at 1.0 ml/l (treatment 3). Watermeal cultivated with the highest level of hydroponic fertilizer resulted in the highest nitrate content at 61.53±0.34 mg/kg of fresh weight, which is higher than a lower one (treatment 3) by about sixfold. The suitable level of hydroponic fertilizer for watermeal cultivation was 1 ml/l of water. The tilapia fish were reared by CD and FWM in combined feeding. Fish cultivated in the control treatment (100% CD feeding) showed the highest growth with no significant difference (p>0.05) when compared to fish cultivated at 70:30 of CD and FWM feeding. The control treatment had the lowest survival rate at 52.00±17.43%, recording a significant difference (p < 0.05) when compared to other treatments. Fish in treatment 2 (70%CD:30%FWM) showed the highest specific growth rate (SGR) as 3.33±0.02 %/day, but no significant difference was detected when compared to 100% CD feeding. Therefore, a combined feeding of 70%CD and 30%FWM was found to be a suitable practice in FWM utilization for rearing the Nile tilapia, Oreochromis niloticus.]]>
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. and Escherichia coli. The isolation of bacterial flora in fish serves as an indicator organism of anthropogenic pressures/activities of the aquatic environment. Their presence causes diseases for humans. The association of pathogenic bacterial species in fish may lead to food safety hazards for the consumers if the fish are handled or prepared improperly.]]>
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winter> autumn> summer, while the concentrations of manganese showed the following results: summer> winter> autumn> spring. Levels of lead in the musculature of both Siganus rivulatus and Pomadasys stridens exceeded the permissible limits proposed by FAO/WHO. Nevertheless, manganese recorded concentrations were within the limits proposed by FAO/WHO for food standards of fish. Heavy metals concentrations were markedly higher in fish tissues compared to water. Liver and gill tissues showed metal concentrations higher than other tissues. In conclusion, these findings indicate that fish can be used as a biomarker for heavy metal pollution in aquatic ecosystems.]]>
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0.05). Value of slope ‘b’ indicated an isometric growth pattern for the majority of parameters. Though the data recorded would aid in fisheries and aquaculture management, further research is recommended with respect to the habitats, gender, and size groups of the species under study.]]>
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