Effects of waterborne exposure to the antidepressant fluoxetine on swimming, shoaling and anxiety behaviours of the mosquitofish Gambusia holbrooki.

F. J. MEIJIDE; R. H. DA CUñA; J. P. PIETRO; L. S. DORELLE; P. A. BABAY; F. L. LO NOSTRO

ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Lugar: Amsterdam; Año: 2018 p. 646 - 655

0147-6513

Chemicalpollution from pharmaceuticals is increasingly recognized as a major hazard tothe aquatic biota. Among the wide variety of pharmaceuticals, fluoxetine (FLX)is one of the most widely prescribed antidepressants, and therefore, it is frequentlyidentified in the aquatic environment. As FLX is designed to alter human behaviourand many physiological pathways are conserved across vertebrates, this drug mayaffect the behaviour of fish living in FLX-polluted environments. Here, we exposedgroups of female mosquitofish Gambusiaholbrooki to waterborne FLX for 14 days, under semi-static conditions withdaily renewal of test solutions. Following exposure, we conducted a set ofbehavioural assays in individual fish, aimed at assessing the effects of FLX ontheir locomotor activity and behavioural responses. We found that FLX impaired swimmingbehaviour at high concentrations (25 ìg/L and 50 ìg/L) but not at low concentrationsclose to environmental levels (1 ìg/L and 5 ìg/L). When swimming activity wasassessed 5 min after transfer of the focal fish to the testing tank, 50 ìg/LFLX was the only concentration showing significant effects. However, when thesame trials were performed 24 h later, 25 ìg/L FLX turned out to be an effectconcentration in addition to 50 ìg/L. Interestingly, these concentrations wouldelicit fish plasma concentrations comprised within the range of humantherapeutic doses. When subjected to a light/dark preference test, fish showedtendency to remain less time in the dark area at high FLX concentrations, thussuggesting an anti-anxiety response. Shoaling behaviour was not affected by FLXexposure. Our study contributes to the growing body of literature evaluatingthe effects of FLX on animal behaviour. Regarding the experimental design usedin behavioural testing, our findings suggest that focal fish should besubjected to long habituation periods, namely of at least a few hours, in orderto better assess the effects of drug exposure.