Evaluation of lead exposition length on the liver and intestinal histoarchitecture of eared dove (Zenaida auriculata)

Abstract

Lead (Pb) is a metal that can produces irreversible damage in living organisms. Some studies had reported that Pb produces histophysiological alterations in the digestive system (mainly liver) of birds; however, the effect of this metal on small intestine has not been fully examined. Additionally, little information is available on Pb disturbances in native birds of South America. The present study aimed to evaluate the effect of different Pb exposure times on blood δ-aminolevulinic acid dehydratase (δ-ALAD) activity and on the histological and morphometric characteristics of the digestive system (liver and proximal intestine) of eared doves (Zenaida auriculata). A decrease of the blood δ-ALAD activity, dilatation of blood vessels and leukocyte infiltrates in intestinal submucosa and muscular layers, and reduction of the enterocyte nuclear diameter and Lieberkühn crypts area were observed. In liver were noted steatosis, proliferation of bile ducts, dilated sinusoids, leukocyte infiltrates, and melanomacrophage centers. The portal tract area and the thickness of the portal vein wall were increased. In conclusion, the results showed that Pb produces histological and morphometric alterations on the liver and small intestine according to the exposure time, which should be considered when the dangerousness of environmental pollutants is evaluated in wild animals.