Effect of Fadrozole Exposure on Socioreproductive Behaviors and Neurochemical Parameters in Betta splendens.

Induction of all-male population in Siamese fighting fish, Betta splendens, has potential application in ornamental fish trade. In addition, the sexually dimorphic nature of aggressive behavior exhibited by this species has made it into an emerging model for behavioral studies. Fadrozole, an aromatase inhibitor, which has been used widely in masculinization, has captivated us to use it in this study. Twenty one days postfertilization (dpf), B. splendens fry were subjected to discrete immersion treatment with various concentrations of fadrozole, and eventually, analyses of various socioreproductive behaviors and analyses of stress markers such as dopamine in brain samples, sex hormones, cortisol, and glucose in plasma samples were performed. We observed that 91% of 50 μg/L fadrozole treated fish developed as males. Interestingly, reproductive analyses of these males gave rise to two subgroups (A and B). Subsequent sociobehavioral analyses demonstrated a timid and subdued behavior in subgroup B males. Furthermore, estimation of stress markers such as dopamine levels in the brain tissue, cortisol, and glucose levels in blood plasma and sex hormone levels in blood plasma exhibited an endocrine disruption-mediated stress leading to altered behavior in these males. These findings will help in understanding the fadrozole-mediated masculinization and behavioral alterations following endocrine disruption.