Diazepam em concentração ambiental altera comportamento em Betta splendens

Abstract

The presence of drugs in the aquatic environment has been reported for some years. However, the impacts on organisms present in these ecosystems are poorly understood. Thus, we investigated the effects of acute exposure to diazepam on the feeding, locomotor, aggressiveness and anxiety-like behaviors in Betta splendens. Behavioral tests were performed on all fish prior to exposure to the drug, designated pre-treatment. After this period, the animals were exposed to the drug for five days, a so-called treatment period, and the tests were performed after 24, 72 and 120 hours of exposure. Three experimental groups were used: Control; Diaz 0.88 μ /L (environmental concentration); and Diaz 8.8 μg/L (concentration 10 times higher than the environmental concentration). Our results demonstrated that diazepam in the environmental concentration is able to reduce aggression and anxiety-like behavior, while in the concentration 10 times greater it is able to increase the locomotor activity. Fish with such behavioral changes can cause changes in the structures of aquatic communities, as they influence growth and reproduction and also increase the risk of predation of exposed organisms. Thus, these data suggest that the presence of psychoactive drugs, such as benzodiazepines, in aquatic ecosystems can cause ecologically important behavioral changes on non-target organisms.