Abordagens in situ e in silico no uso das aves para o biomonitoramento ambiental de genotoxicidade em áreas agrícolas no Cerrado

Abstract

Birds have often played an important role as environmental bioindicators, and different species can be useful due to their bioaccumulating capacity. The micronuclei test is a cytologic technique used for accessing DNA and is a biomarker for damage to DNA. This study analysed the Cerrado avian community, especially the efficiency of the blue-black grassquit (Volatinia jacarina) in response to pesticide contamination in situ on different-sized coffee farms in southeast Brazil, we proposed an in silico approach to build a phylogenetic gene tree based on the COI gene, owing, especially, to compare the species of the birds most related. The specific aims of the work were (a) to feature a set of community of birds of the Cerrado as environmental indicators associated with pesticides uses performing the erythrocytes micronuclei test of the birds; (b) to assess if the micronuclei frequency was related with the trophic guild of the birds; (c) to verify allometric relationships between birds and the MN frequency; (d) to build with bioinformatics tools, a phylogenetic gene tree based on mtDNA with a better way to compare, evolution assumptions. The birds were captured in three group sizes of farms located at Monte Carmelo, Minas Gerais, Brazil. All farms use the same classes of pesticides but with a progressive increase of concentration and frequency of application. Blood samples were collected in all birds collected via the metatarsal vein with a needle and a syringe of appropriate size. After that, one or two drops of blood were smeared on a slide to perform the staining techniques. Eighty-two individuals of 21 bird species belonging to 11 families that were found in all study areas were used to evaluate micronuclei (MN) frequency. Two hundred and fifty-two MN were counted in every area of the study. The MN average count was 3/10,000 erythrocytes, and 17.1% of all bird species exhibited no MN. The average MN was 1.29 ± 0.69 in small farms, 2.59 ± 1.65 in medium farms, and 5.41 ± 1.34 in large farms. Small farms accounted for 14.3% of MN frequency, medium farms 27.8%, and large farms 57.9%. V. jacarina was the most abundant species found and displayed a sensitive response to environmental contamination. Pesticides appear to induce MN formation in a dose-dependent way when farms are analysed according to their area. Therefore, biomonitoring birds remains an efficient means to detect environmental pollutants, especially pesticides. V. jacarina responds as a sensitive biomonitor, showing a dose-dependent response to pesticides used in coffee farms. Due to the high diversity of birds in Brazil, we propose an alternative tool to cluster different species of birds in the same analysis just to help in researches the need of a cheap and fast data collection, as with the case of environmental biomonitoring using the MN test, as the principle technique, being faster and cheaper than possibly before. Therefore, a huge sample effort would violate these principles. V, jacarina was the specie most frequently sampled and showed a sensitive response to environmental contamination. Moreover, birds as biomonitors remain efficient in detection of environmental pollutants, especially pesticides. V. jacarina acted as a sensitive biomonitor, showed a size-dependent response to pesticides used in the coffee farms.