Ecotoxicology of azametifos insecticide and development of environmental safety protocol for tambaqui (Colossoma macropomum)

Abstract

Among the main problems during the productive cycle of fish, the occurrence of ecto and endoparasites causes economic losses due to the mortalities in the stages of larviculture, raising and in the initial phases of fattening. Among the parasites of fish can be highlighted: the monogenetic ones that present great diversity in number, morphology and ecology. Organophosphorus compounds have been widely used as insecticides, acaricides and anthelmintic compounds for decades in world aquaculture. Among the drugs with potential to be used as ectoparasiticide is the azamethiphos organophosphate used as a moderately toxic, non-bioaccumulative, highly water-soluble, volatile insecticide and should not be leached into groundwater. It is a neurotoxic chemical and acetylcholinesterase inhibitor. Thus, the objective of this research proposal will be: i) to evaluate the acute toxicity of azamethiphos to non-target organisms and bioindicators of environmental exposure (aquatic plants - Azolla caroliniana, Lemna minor and Wolffia brasiliensis), for shrimp mollusc Pomacea canaliculata freshwater pitu (Macrobrachium acanthrus) and zebrafish (Danio rerio) and mato grosso (Hyphessobrycon eques); ii) evaluate the acute and chronic toxicity of the tambaqui (Colossoma macropomum) target organism; to analyze the histological and hematological effects on tambaqui (C. macropomum) of exposure to azamethiphos; iii) analyze protein expression to evaluate the degradation of acetylcholine from tambaqui fish (C. macropomum) after azamethiphos application. For this purpose, acute toxicity tests for bioindicator organisms will be performed in accordance with current national and international standards. For tambaqui (C. macropomum) acute and chronic toxicity tests will also be performed in accordance with current national standards. To determine the possibility of use and the possible effects of exposure of tambaqui to azamethiphos, a treatment simulation and exposure recovery assay will be performed to evaluate the possible histopathological, hematological and protein expression effects involved in the azamethiphos response. (AU)