RESUMEN
This work assesses the concentration of As, Cd, Pb, Hg, and Al in three of Tilapia species and catfish caught from Lake Mariut. As well as the human health risk and muscle biochemical composition. Besides, the antioxidant responses of different species. The average metal concentration order was Pb> As> Cd> Al> Hg. The Cd and Pb levels in all species; besides, the Hg levels in Oreochromis niloticus and Oreochromis aureus exceeded the maximum limits set by FAO, European legislation, and FAO/WHO. The human health risk was assessed using estimated dietary intakes, the target hazard quotient (THQ), and the carcinogenic risk (CR). THQAs was >1 in all examined fishes and closer to 1 in THQCd, Hg. As well, CR level for As was higher than the permissible value. Tilapia zillii showed significant decreases in carbohydrates compared to Clarias gariepinus; also, ash content compared to C. gariepinus, O. niloticus, and O. aureus. Furthermore, water content compared to O. aureus. In contrast, significant increases of SOD in O. niloticus compared to C. gariepinus. In addition, CAT and GPx in O. aureus compared to C. gariepinus. Also, GR in both O. niloticus and O. aureus compared to C. gariepinus, and GSH in all of Tilapia spp. compared to C. gariepinus. Data obtained provide evidence of health risks to the consumers. Therefore, more caution is required.
RESUMEN
The effects of chronic exposure to total ammonia nitrogen (TAN) concentrations on the brain monoamines and ATPases of Nile tilapia, Oreochromis niloticus fingerlings, were studied. The period of exposure was 70 consecutive days, and the initial weight of the fingerlings was 18+/-2.1g. In addition to the control, three treatment groups exposed to 2.5 (low), 5 (medium), and 10 (high) mg TANL(-)(1) concentrations were tested. The unionized ammonia nitrogen (NH(3)) levels calculated in mgL(-)(1) were 0.059, 0.185, and 0.575 in aquaria at 26 degrees C. The brain monoamines were serotonin (5-HT), dopamine (DA), and norepinephrine (NE), as well as their derivatives, 5-hydroxyindoleacetic acid (5-HIAA) and dihydroxyphenylacetic acid (DOPAC). Compared with the controls, the levels of brain monoamines and Na(+)/K(+)- and Ca(2+)-ATPase activities were not significantly altered in fish exposed to low TAN concentration. However, there was a significant decrease in 5-HT, DA, and NE levels, and a significant increase in both serotonergic (5-HIAA/5-HT) and dopaminergic (DOPAC/DA) activities of fish exposed to medium TAN and high TAN concentrations. The activities of brain Na(+)/K(+)- and Ca(2+)-ATPases of fish exposed to medium TAN and high TAN concentrations significantly increased, while Mg(2+)-ATPase did not significantly change compared with that of the controls. The quantity of the detected alterations increased in fish exposed to high TAN concentration.