Distúrbios fisiológicos em pós-larva de macrobrachium rosenbergii submetidos a exposição aguda por glifosato: efeitos na defesa antioxidante, colinesterase e metabolismo de aminoácidos

Abstract

Agriculture has been bringing several impacts to the environment in the way it is currently done, where production entails high use of pesticides, which has an important role mainly due to the toxic potential, lack of efficient mechanisms of degradation, accumulation in the body and transference between the trophic chains. The continental cultivation of the freshwater shrimp Macrobrachium rosenbergii, in areas permeated by crops, raises the question as to the effect of glyphosate exposure on these animals. Thus, this work aimed to analyze the effect of glyphosate exposure on physiological parameters in post-larvae of freshwater shrimp (M. rosenbergii) through the analysis of biochemical biomarkers. Freshwater shrimp M. rosenbergii post-larvae, which underwent acclimatization and were exposed to glyphosate, were used in 1500 animals with a mean weight of 0.024 g. The trial was carried out separating the experimental group exposed to glyphosate with 100 mg/L and the control group, and the animals were collected for subsequent biochemical tests in 2, 6, 9, 12, 24, 48, 96 hours. Tests for antioxidant defense, amino acid metabolism and neurotoxic effects (cholinesterases) were performed. In the experiment, 41 animal deaths were identified within the first 6 hours, in addition to irregular swimming behavior in the first 12 hours in the exposed group. An increase in cholinesterase activity was observed at 2, 6, and 9 hours, and then a decrease in cholinesterase activity at 48 hours. There was no significant variation in CAT activity throughout the experiment. In 6 hours of the experiment there was an increase in GST activity and a decrease in 9 hours. There was an increase in GSH concentration at 12, 24 and 48 hours after exposure. The concentration of LPO increased at 96 hours after the beginning of the experiment and exposure. AST showed induction in 6 hours, ALT showed the same in 6, 48 and 96 hours after the beginning of the experiment. GLDH showed decreased activity at 9 hours, increased at 48 hours, and decreased at 96 hours in the exposed group. The glyphosate exposure causes lethal effects, behavioral and physiological changes in M. rosenbergii after acute exposure. The physiological changes are related, among others, to interferences in amino acid metabolism, cholinesterases and in the antioxidant defense of the animals.