Characterization of sickness behavior in zebrafish

• Published in: Brain, behavior, and immunity Vol. 73; pp. 596 - 602
• Main Authors: Kirsten, Karina, Soares, Suelen Mendonça, Koakoski, Gessi, Carlos Kreutz, Luiz, Barcellos, Leonardo José Gil
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.10.2018
• Subjects: Animals; Behavior, Animal - physiology; Brain; Brain - metabolism; Cytokine; Cytokines - metabolism; Disease Models, Animal; Exploratory behavior; Exploratory Behavior - physiology; Female; Illness Behavior - physiology; Immune system; Immune System - metabolism; Interpersonal Relations; Locomotion - immunology; Locomotion - physiology; Male; Motor Activity - physiology; Neurons - metabolism; Social behavior; Zebrafish - immunology; Zebrafish - physiology; Brain; Social behavior; Exploratory behavior; Cytokine; Immune system
• ISSN: 0889-1591; 1090-2139; 1090-2139
• DOI: 10.1016/j.bbi.2018.07.004

•After an inflammatory response zebrafish reduces locomotion, social interaction and exploration.•The pro-inflammatory cytokines are upregulated in zebrafish brain after an inflammatory process in periphery.•The immune system causing behavior changes in zebrafish. In a previous study we showed a clear relationship between immune system and behavior in zebrafish and we hypothesized that the immune system is capable of inducing behavioral changes. To further investigate this subject and to address our main question, here we induced an inflammatory response in one group of fish by the inoculation of formalin-inactivated Aeromonoas hydrophila bacterin and compared their social and exploratory behavior with control groups. After the behavioral tests, we also analyzed the expression of cytokines genes and markers of neuronal activity in fish brain. In the bacterin-inoculated fish, the locomotor activity, social preference and exploratory behavior towards a new object were reduced compared to the control fish while the expression of proinflammatory cytokines in the brain was upregulated. With this study we demonstrated for the first time that the immune system is capable of causing behavioral changes that are consistent with the sickness behavior observed in mammals.