Effects of exogenous elevation of corticosterone on immunity and the skin microbiome of eastern newts ()

DOI

10.1098/rstb.2022.0120

Document Type

Journal Article

Publication Date

7-31-2023

Publication Title

Philosophical transactions of the Royal Society of London. Series B, Biological sciences

Volume

378

Issue

1882

First Page

20220120

Keywords

chytridiomycosis, glucocorticoid, physiology, salamander, skin bacteria, stress

Abstract

The amphibian chytrid fungus, () threatens salamander biodiversity. The factors underlying susceptibility may include glucocorticoid hormones (GCs). The effects of GCs on immunity and disease susceptibility are well studied in mammals, but less is known in other groups, including salamanders. We used (eastern newts) to test the hypothesis that GCs modulate salamander immunity. We first determined the dose required to elevate corticosterone (CORT; primary GC in amphibians) to physiologically relevant levels. We then measured immunity (neutrophil lymphocyte ratios, plasma bacterial killing ability (BKA), skin microbiome, splenocytes, melanomacrophage centres (MMCs)) and overall health in newts following treatment with CORT or an oil vehicle control. Treatments were repeated for a short (two treatments over 5 days) or long (18 treatments over 26 days) time period. Contrary to our predictions, most immune and health parameters were similar for CORT and oil-treated newts. Surprisingly, differences in BKA, skin microbiome and MMCs were observed between newts subjected to short- and long-term treatments, regardless of treatment type (CORT, oil vehicle). Taken together, CORT does not appear to be a major factor contributing to immunity in eastern newts, although more studies examining additional immune factors are necessary. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.

Open Access

37305906 (pubmed); PMC10258667 (pmc); 10.1098/rstb.2022.0120 (doi)

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