title: Biochemical and histopathological changes in liver of the Nile tilapia from Egyptian polluted lakes.
abstract: The aim of the present study was to analyze the impact of environmental contamination on oxidative stress and histopathologic biomarkers in liver of the Nile tilapia, Oreochromis niloticus, collected from four sites that differ in their extent of pollution load, including heavy metals: the southeast basin (SEB), main basin (MB), and northwest basin (NWB) of Lake Mariut as well as Boughaz El-Maadiya, a channel in Lake Edku. The SEB was the less-impacted site, and thus considered as a reference. High concentrations of heavy metals (cadmium, copper, iron, lead, zinc, and manganese) were detected in fish liver at sites with anthropogenic pressure. All biomarkers, lipid peroxidation (in the MB, NWB, and Lake Edku), superoxide dismutase (in the MB and NWB), and glutathione peroxidase, and reduced glutathione (in the NWB) were found to be significantly higher compared to the reference values. Catalase, glutathione reductase, and glucose-6-phosphate dehydrogenase showed a varied response and displayed significantly lower activities in the polluted sites. Certain hepatic lesions, detected microscopically, were stimulated in fish from the MB and NWB, reflecting the high contamination of these areas. These included foci of necrosis, melanomacrophage infiltration, congestion, nuclear pyknosis, and extensive vacuolation corresponding to relatively higher lipid content. Overall, our results suggest that the selected biomarkers are useful for the assessment of pollution impacts in natural aquatic environments influenced by multiple pollution sources. The existence of chronic background pollution of the test sites implies that the observed biomarker responses cannot be solely attributed to heavy metals.
authors.affiliation: Department of Biological Sciences, Faculty of Science, King Faisal University, Al-Hassa, Saudi Arabia Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt aabdelmoneim@kfu.edu.sa.
authors.forename: Ashraf M
authors.initials: AM
authors.lastname: Abdel-Moneim
authors.affiliation: Department of Zoology, Faculty of Science, Alexandria University, Alexandria, Egypt Department of Biology, Faculty of Applied Sciences for Girls, Um Al Qura University, Mecca, Saudi Arabia.
authors.forename: Amina E
authors.initials: AE
authors.lastname: Essawy
authors.affiliation: Department of Zoology, Faculty of Science, Mansoura University, Mansoura, Egypt.
authors.forename: Nariman K
authors.initials: NK
authors.lastname: Badr El-Din
authors.affiliation: Department of Zoology, Faculty of Science, Mansoura University, Mansoura, Egypt Department of Biological Science, Faculty of Science and Home Economics, King Khalid University, Jedda, Saudi Arabia.
authors.forename: Nahed M
authors.initials: NM
authors.lastname: El-Naggar
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis; D023681:Cichlids; D004534:Egypt; D006651:Histocytochemistry; D060106:Lakes; D008099:Liver / Q000737:chemistry / Q000187:drug effects / Q000473:pathology; D019216:Metals, Heavy / Q000032:analysis*; D018384:Oxidative Stress / Q000187:drug effects; D014874:Water Pollutants, Chemical / Q000032:analysis*; D014877:Water Pollution, Chemical / Q000032:analysis*
chemical_list: D015415:Biomarkers; D019216:Metals, Heavy; D014874:Water Pollutants, Chemical
keywords: Biomarkers; fish; histopathology; liver; oxidative stress