Reducing the Noise in Behavioral Assays: Sex and Age in Adult Zebrafish Locomotion

Abstract

Many assays are used in animal model systems to measure specific human disease-related behaviors. The use of both adult and larval zebrafish as a behavioral model is gaining popularity. As this work progresses and potentially translates into new treatments, we must do our best to improve the sensitivity of these assays by reducing confounding factors. Scientists who use the mouse model system have demonstrated that sex and age can influence a number of behaviors. As a community, they have moved to report the age and sex of all animals used in their studies. Zebrafish work does not yet carry the same mandate. In this study, we evaluated sex and age differences in locomotion behavior. We found that age was a significant factor in locomotion, as was sex within a given age group. In short, as zebrafish age, they appear to show less base level locomotion. With regard to sex, younger (10 months) zebrafish showed more locomotion in males, while older zebrafish (22 months) showed more movement in females. These findings have led us to suggest that those using the zebrafish for behavioral studies control for age and sex within their experimental design and report these descriptors in their methods.

Assessing Social Engagement in Heterogeneous Groups of Zebrafish: A New Paradigm for Autism-Like Behavioral Responses

“…Recent studies [37], [38] confirm our view that male and female zebrafish show clearly distinct behavioral patterns. We used only females as to avoid complicating social cohesion by occurrences of antagonistic behaviors.…”

Evidence of an Association between Age-Related Functional Modifications and Pathophysiological Changes in Zebrafish Heart

“…A limitation of the current research is that the zebrafish life span data in the present study did not include sex-specific data although sex-specific differences in behavior [40] and gene expression [8] have been reported in aging. Also, although female zebrafish were used in the initial population, accurate sex determination based upon subjective morphological criteria such as the criteria we used is difficult to ascertain with certainty in zebrafish.…”

Zebrafish models for translational neuroscience research: from tank to bedside

“…Similarly, in the cocaine withdrawal model, females exhibit earlier onset of behavioral withdrawal symptoms than male fish (who show more robust anxiogenic-like withdrawal phenotypes [22]). Given well-known sex differences in human behaviors, the effects of sex on zebrafish phenotypes in various behavioral models necessitate further experimentation (e.g., see recent data on sex and age differences in zebrafish locomotion [117]).…”