Juvenile zebrafish: Some environmental enrichment paradigms produce anxiolytic-like effects and improve immunity

Different Influences of Anxiety Models, Environmental Enrichment, Standard Conditions and Intraspecies Variation (sex, personality and strain) on Stress and Quality of life in Adult and Juvenile Zebrafish: A Systematic Review. Jhon Buenhombre et al. Neuroscience & Biobehavioral Reviews, September 27 2021. https://doi.org/10.1016/j.neubiorev.2021.09.047

Highlights

• Some environment>al enrichment paradigms produce anxiolytic-like effects and improve immunity.

• Unpredictable chronic stress and aquarium-related stressors induce anxiogenic-like effects.

• Developmental, social, intraspecies variation and test-related factors affect environmental manipulations.

• Comparison of different levels of stress would define optimal ranges of husbandry, standardisation and stress resilience.

Abstract: Antagonist and long-lasting environmental manipulations (EM) have successfully induced or reduced the stress responses and quality of life of zebrafish. For instance, environmental enrichment (EE) generally reduces anxiety-related behaviours and improves immunity, while unpredictable chronic stress (UCS) and aquarium-related stressors generate the opposite effects. However, there is an absence of consistency in outcomes for some EM, such as acute exposure to stressors, social enrichment and some items of structural enrichment. Therefore, considering intraspecies variation (sex, personality, and strain), increasing intervention complexity while improving standardisation of protocols and contemplating the possibility that EE may act as a mild stressor on a spectrum between too much (UCS) and too little (standard conditions) stress intensity or stimulation, would reduce the inconsistencies of these outcomes. It would also help explore the mechanism behind stress resilience and to standardise EM protocols. Thus, this review critically analyses and compares knowledge existing over the last decade concerning environmental manipulations for zebrafish and the influences that sex, strain, and personality may have on behavioural, physiological, and fitness-related responses.

Keywords: Stress resiliencezebrafishenvironmental enrichmentstrainsexpersonalityneurophysiologybehaviour

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EE can be housing conditions promoting social interactions, sensory-motor and cognitive stimulation with novel stimuli and physical exercise