Immunological status of some edible fishes exposed to parasitic infections in relation to heavy metals pollution

In this study, six heavy metals (Pb, Fe, Cu, Ni, Cd, and Mn) have been measured in water, and muscles from mullet ( Mugil cephalus ), tilapia ( Oreochromis niloticus ), and African catfish ( Clarias gariepinus ) collected from Lake Manzal, Egypt. In addition, the existence of different encysted metacercariae in fish muscle with an evaluation of cell-mediated immune response in infected muscles was also investigated. Water samples generally contained less than the permissible level of heavy metals. The metal accumulation levels in muscle were: Pb > Ni > Cd > Cu > Fe > Mn. The levels of Pb and Ni in the muscles exceed the permissible limits, while the concentration of Mn varied significantly ( p