Dados do Trabalho

Título

LONG-TERM APPLICATION OF COMPOSTED MANURES AND ITS EFFECTS ON ANTIBIOTIC RESISTANCE GENES IN TROPICAL SOILS

Resumo

Animal manure management strategies, such as thermophilic composting and stockpiling, should be investigated in order to find effective alternatives in the reduction of antibiotic resistance genes (ARGs) in manure, mitigating the risk of dissemination of these pollutants in the soil . Additionally, the interface between the application of manure and heavy metals in the soil on ARGs is poorly known. Thus, the objective of this work is to evaluate the long-term effect of the application of composted manure in ARGs, in two sets of parallel soils with acceptable levels of heavy metals and a set of parallel soils polluted with these elements. For this, samples were collected from three areas: i) one treated with annual application of chicken litter plus cattle manure compost and contaminated with heavy metals; ii) other treated with poultry litter compost, and iii) another treated with stockpiled pig manure. Samples without manure application were also collected on parallel areas, in all locations. The identification of ARGs was performed by sequencing the soil metagenome, using the DeepArg software. ARGs composition and soil physicochemical attributes connections were evaluated using Redundancy analysis (RDA). For all sets of soils, there was no increase in the abundances of ARGs after successive manure applications. In the uncontaminated soils, ARGs profile was modulated by soils’ pH and available P contents that enhanced with manuring. In contaminated soils, the high heavy metal contents, especially of Cu, dictated ARGs profile, that did not differ whether manured or not. Therefore, the use of composted manure seems to be a good strategy to remediate the dissemination of ARGs in soils. In addition, high heavy metal content is a major factor modulating ARGs profile in soils, followed by pH and available P contents in uncontaminated soils.

Palavras-chave

ARGs; soil; manure

Instituição financiadora

FAPESP, CAPES e CNPq