Personality and repeated social defeat affect health condition and gene expression in the skin and intestines in zebrafish

Abstract

Personality traits and acquired experience affect the capacity of an individual to cope with environmental and social changes. Behavioural adaptation and physiological alterations are important to prepare the body for these potential challenges. Whether inherited traits or acquired social rank (reflecting stress levels) are more important and how different personality-social rank combinations affect an individual's health is not well understood. One important aspect of health status is the function of biological barriers, as they represent the first line of defence of an organism. In the current study, we used a model of social defeat stress applied to a bold and a shy line of zebrafish. The Fulton's condition factor was determined, and gene expression analysis was performed on skin and intestines. The differences between lines explained a major part of the transcriptional changes observed as compared to differences in social rank. Additionally, shy fish that experienced repeated social defeat presented a poor body condition, accompanied by changes in gene expression suggesting inflammation in the gut. In the skin, shy fish showed a transcriptional enrichment of pathways related to cell division as well as increased expression of the stress response-associated gene crh2r. Together, these results complement our previous work and show that shy loser fish experience important changes not only in behaviour but also in their biological barriers, potentially putting their overall health at higher risk.