Análise do Transcriptoma de Fígado do Tambaqui (Colossoma macropomum) Exposto ao Organofosforado Triclorfon

Abstract

Organophosphate compounds are commonly used in fish farming systems to control fish parasites that can affect production and cause economic damage. However, studies over the years have shown that these compounds can not only combat the proliferation of parasites, but also cause harm to the animals being treated. Trichlorfon is one of the organophosphate compounds used in fish farming for this purpose, with its dosage varying according to the organism it seeks to eliminate. Reports of damage to oxidative stress pathways, imbalance in biochemical pathways responsible for cellular respiration, damage to DNA, impairment of ionic transport pathways, activation of pathways linked to tumorigenesis and apoptosis and autophagy pathways are common in exposed fish. Furthermore, damage to tissues, especially the liver and gills, is common. This work sought to define the LC50-96h of trichlorfon for the species Colossoma macropomum (tambaqui) and evaluate, through RNA-Seq, the genes related to the response in the liver of tambaqui specimens exposed to 50% of the LC50-96h (0.435 mg/ L) of trichlorfon for 96 hours. The LC50-96h for the species was defined at a value of 0.870 mg/L, points of necrosis were also found in some tissues of the exposed fish and they lost their swimming balance when exposed to the last concentration (3.2 mg/L). RNA-Seq analysis showed about 176 genes differentially expressed in the samples exposed to trichlorfon, compared to the control group where these genes participate in several exposure response pathways. GO analysis showed the enriched functions, where most of the mapped genes are solute carriers and participate in functions such as transmembrane transport activity, transport activity and ion transport. The analysis of enriched pathways through KEGG showed around 63 pathways enriched by exposure, including the xenobiotic metabolism pathway through cytochrome p450, the drug metabolism pathway through cytochrome p450 and the drug metabolism pathway involving other enzymes. The data found in this work corroborate results described in the literature for other fish species, as well as providing support for further studies on the exposure of fish to organophosphate compounds, mainly trichlorfon.