ENVIRONMENTALLY RELEVANT DOSES OF BISPHENOL A TRIGGER SEX - AND DOSE-SPECIFIC BEHAVIORAL CHANGES IN DANIO RERIO

Resumo

INTRODUCTION: Bisphenol A (BPA) is a chemical widely found in plastics and resins, leading to continuous exposure to both humans and animals. Even at low concentrations, BPA acts as an endocrine disruptor, potentially affecting neurological functions and inducing behavioral changes. OBJECTIVE: This study aimed to investigate whether BPA concentrations considered safe for humans induce behavioral alterations in adult zebrafish. MATERIALS AND METHODS: Danio rerio adults (WT) were maintained in tanks with water at a controlled temperature of 27 °C, under a 14 h light/10 h dark photoperiod. Fish were fed twice daily at 3% of their body weight. The animals were exposed for 60 days to one of the following diets: control, BPA 4 µg/kg, or BPA 50 µg/kg. Every 15 days, body weight was measured to adjust feeding. After exposure, three behavioral tests were conducted: (i) Novel Tank Task, where fish were introduced to a novel environment; (ii) Social Preference Test, with a tank containing conspecifics placed at one end of the testing tank; and (iii) Aggression Test, using a mirror positioned at a 45° angle to simulate an intruder. Behaviors were recorded and analyzed using Any-Maze, and statistical analyses were performed with GraphPad Prism. Although housed in groups, males and females were assessed separately. RESULTS AND CONCLUSION: In the Novel Tank Task, exposure to 4 µg/kg BPA significantly increased immobility time and frequency in both sexes, indicating an anxiogenic effect. BPA 50 µg/kg did not alter behavior in this test. In the Social Preference Test, females exposed to BPA 4 µg/kg showed more entries and less time spent near conspecifics; and males exhibited similar alterations at both concentrations. In the Aggression Test, increased biting behavior was observed only in females fed on BPA50 µg/kg, with no changes in proximity to the mirror across groups. BPA induced sex- and concentration-specific behavioral effects in Danio rerio, with 4 µg/kg causing anxiogenic and social alterations in both sexes, and 50 µg/kg increasing aggression in females. The findings highlight the neurobehavioral sensitivity to environmentally relevant BPA concentrations. Key-words: Endocrine disruptors; Behavioral alterations; zebrafish This work was financed by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Brazil.