First evidence of lead-induced impairment of intestinal digestive enzyme activity in birds

Lead (Pb) is a prevalent toxic metal in contaminated ecosystems, posing a real threat to living organisms. Although birds are highly sensitive to Pb, there is little information on its impact on the avian digestive system. This study was designed to compare the effects of chronic Pb exposure (for 15 and 30 days) on the activities of digestive enzymes-aminopeptidase-N (APN), maltase-glucoamylase (MG), and sucrase-isomaltase (SI)-between eared doves (Zenaida auriculata) and house sparrows (Passer domesticus). Our results showed that Pb-exposed sparrows exhibited inhibited digestive enzyme activities compared to the control, while treated doves did not show significant changes in enzyme activity. This difference in sensitivity between sparrows and doves may be due to physiological differences and water consumption. In conclusion, this study provides the first evidence of inhibited APN, MG, and SI activity in sparrows as a result of chronic Pb exposure through drinking water. Furthermore, our work contributes to the understanding of Pb toxicology in the digestive system of birds and its effect on the acquisition of energy, which should be considered when evaluating the impact of environmental pollutants on wildlife.