Evaluation of potential immunotoxic effects of iron oxide nanoparticles (IONPs) on antioxidant capacity, immune responses and tissue bioaccumulation in common carp (Cyprinus carpio)

Nanoparticles can be toxic and put human and animals' life at risk. The present work was carried out to evaluate the possible immunosuppressive effects of water borne iron oxide nanoparticles (IONPs) and the FeCl3 on immune components of common carp (Cyprinus carpio). Fish were exposed to a series of chronic levels of 25%, 50%, and 75% of IONPs LC50 96 h concentration (referred to as control, NP1, NP2, and NP3 respectively) or FeCl3 (same concentrations as IONPs referred to as S1, S2, and S3 respectively) for 21 days. Results revealed alterations in blood parameters, where IONPs significantly decreased number of white blood cells at all concentrations. Glucose and cortisol increased in all exposed fish after 21 days, suggesting activation of the maintenance mechanism cascade against a chronic stressor. IONPs or FeCl3 significantly accumulated in liver tissue of exposed fish. Immune responses were remarkably decreased in serum and skin mucus in response to IONPs or FeCl3. These components were at lowest levels in fish exposed to the highest concentrations of IONPs and FeCl3. The findings of the present study suggested that IONPs is accumulated in fish liver and intestine, where they may exhibit immunotoxicity. [Display omitted] •Iron oxide nanoparticles severely suppress common carp's immune system.•Intestine tissue seems to accumulate larger amounts of iron oxide nanoparticles.•Iron oxide nanoparticles were found more immunotoxic than FeCl3 salt for common carp.•Both iron oxide nanoparticles and FeCl3 activate stress responding cascade.