Moderate early-life stress improves adult zebrafish (Danio rerio) spatial short-term memory but does not affect social and anxiety-like responses

Early-life stress (ELS) is defined as a short or chronic period of trauma, environmental or social deprivation, which can affect different neurochemical and behavioral patterns during adulthood. Zebrafish (Danio rerio) have been widely used as a model system to understand human neurodevelopmental disorders and display translationally relevant behavioral and stress-regulating systems. In this study, we aimed to investigate the effects of moderate ELS by exposing young animals (six weeks post-fertilization), for three consecutive days, to three stressors, and analyzing the impact of this on adult zebrafish behavior (sixteen weeks post-fertilization). The ELS impact in adults was assessed though analysis of performance on tests of unconditioned memory (free movement pattern Y-maze test), exploratory and anxiety-related task (novel tank diving test) and social cohesion (shoaling test). Here, we show for the first time that moderate ELS increases the number of pure alternations compared to pure repetitions in the unconditioned Y-maze task, suggesting increased spatial short-term memory, but has no effect on shoal cohesion, locomotor profile or anxiety-like behavior. Overall, our data suggest that moderate ELS may be linked to adaptive flexibility which contributes to build resilience in adult zebrafish by improving short-term spatial memory performance.