Animals (Aug 2023)

Assessing Chronodisruption Distress in Goldfish: The Importance of Multimodal Approaches

  • Nuria Saiz,
  • Lisbeth Herrera-Castillo,
  • Nuria de Pedro,
  • María Jesús Delgado,
  • Sven David Arvidsson,
  • Miguel Ángel Marugal-López,
  • Esther Isorna

DOI
https://doi.org/10.3390/ani13152481
Journal volume & issue
Vol. 13, no. 15
p. 2481

Abstract

Read online

Chronodisruption caused by factors such as light at night and mistimed meals has been linked to numerous physiological alterations in vertebrates and may be an anxiogenic factor affecting welfare. This study aims to investigate whether chronodisruption causes measurable changes in the anxiety responses of goldfish under two conditions: randomly scheduled feeding (RF) and continuous light (LL). Anxiety-like behavior was assessed in the open field with object approach and black/white preference tests, which had been validated using diazepam. An increased thigmotaxis response and decreased object exploration under both chronodisruption protocols indicated anxiety states. Furthermore, locomotor activity was increased in LL fish. The black/white preference test discriminated anxiolysis induced by diazepam but was unable to detect anxiety caused by chronodisruption. Plasma cortisol increased in both RF and LL fish throughout the experiment, confirming that both conditions caused stress. The LL fish also showed an apparently desensitized hypothalamus–pituitary–interrenal HPI axis, with a decrease in pomc and crf expression. Individual analysis found no correlation between anxiety-like behavior and stress axis activation nor between scototaxis and thigmotaxis responses. However, individual differences in sensitivity to each test were detected. Altogether, these results highlight circadian disruption as a stressor for fish and endorse a multiple variable approach for reliably assessing animal discomfort.

Keywords