How can different land use impact aquatic organisms? An evaluation of metabolic alterations during embryonic development of freshwater fish, Rhamdia quelen

Abstract

Chemical compounds used in agricultural activities are constantly leaching to water bodies where they can potentially cause damage to non-target organisms. In this study, we attempt to understand how the change in land use and exposure to xenobiotic substances may alter the metabolism and neurotoxicity during the development of native fish. Embryonic development of Rhamdia quelen was used as a quality indicator of two different aquatic environments, a stream considered impacted (Tormenta) and another reference (Manoel Gomes). The eggs were exposed to water collected from the reference and impacted streams during the development period (12h, 24h, 48h, and, 72h). Changes in the activity of energy metabolism enzymes (HK, PFK, LDH, CS, MDH) and the antioxidant defense system (CAT, GPX, GR, GST) were observed in animals exposed to impacted stream water. The entry of xenobiotic compounds into rivers through the leaching of chemical molecules existent in the soil causes activation of enzymes with a detoxification function. Furthermore, inhibition of cholinesterase enzyme activity indicates contamination by anticholinesterase compounds such as organophosphates and carbamates. Sites with constant use of these compounds can trigger harmful effects to organisms in the early stages of fish development and alter the body's metabolic and defense enzymatic activities.