Hepatic function and structure in feral pigeons (Columba livia domestica) exposed to zinc oxide nanoparticles

Background Broad applications of nanoparticles have invoked the concerns about their impacts on living organisms. This study aimed to evaluate the possible changes that could take place in the liver of feral pigeons ( Columba livia domestica ) after oral ingestion of zinc oxide nanoparticles (nano-ZnO). Methods Pigeons were acclimatized to the laboratory conditions with a photoperiod of 12:12 h at 20 ± 2 ˚C for 14 days and maintained on seed mixture and clean tap water ad libitum. The birds were randomly assigned to five groups of 10, including one control group and four experimental groups orally receiving 0, 30, 50, and 75 mg/kg b.w. of nano-ZnO through oral gavage for 7 and 14 consecutive days. Results The oxidative stress (OS) biomarkers, namely lipid peroxidation content and catalase activity in the liver samples, and the level of hepatic necrosis markers (ALT, AST, and ALP) in the blood sera were increased in a concentration-dependent manner. Meanwhile, the total antioxidant capacity of liver samples measured by FRAP test was reduced. Histopathological changes revealed inflammatory cell infiltration, swelling area, vacuolization, and expansion of interstitial spaces in liver samples exposed to 75 mg/kg nano-ZnO. Conclusions Nano-ZnO induced obvious hepatotoxicity in the liver of pigeons, where the OS pathway may be the potential mechanism underlying this toxicity.