Genotoxic analysis of Blue-and-Yellow Macaw (Ara ararauna) nestlings in an urban environment in the Central-West region of Brazil

The use of biomarkers for the evaluation of environmental quality allows for early detection of biological effects caused by genotoxins. Free-living birds in urban environments are excellent organisms for modeling studies of the biological effects of environmental pollutants. This study investigated the frequency of micronuclei and other erythrocyte nuclear abnormalities in Ara ararauna nestlings born in an urban environment. We monitored 180 nests with a total of 123 nestlings, and from these we collected blood samples from 48 individuals to conduct micronucleus analysis and scan for other erythrocyte abnormalities. Nests were grouped based on environmental characteristics such as the presence of vegetated areas and movement of vehicles in adjacent areas. A total of 37 micronuclei and 1047 other nuclear abnormalities were documented, wherein cells with notched nuclei were the most frequently witnessed abnormality (44.6%), while anucleate cells were the least frequent abnormal characteristic described (2.8%). The average frequency of micronuclei was 0.7/5,000, and the average frequency of other nuclear abnormalities was 22.5/5,000. The proportion of nuclear abnormalities was greater in nests near areas with a high volume of vehicle traffic and a reduced area of vegetation. This is the first study that documents the presence of nuclear abnormalities in erythrocytes in free-living nestlings of Ara ararauna in urban environments. These results highlight the importance of green areas in urban environments to support better conditions for animals.