Publication
Probiotic treatment restores protection against lethal fungal infection lost during amphibian captivity
Publisher:
The Royal Society
Date:
28-09-2016
DOI:
10.1098/RSPB.2016.1553
Abstract: Host-associated microbiomes perform many beneficial functions including resisting pathogens and training the immune system. Here, we show that hibians developing in captivity lose substantial skin bacterial ersity, primarily due to reduced ongoing input from environmental sources. We combined studies of wild and captive hibians with a database of over 1 000 strains that allows us to examine antifungal function of the skin microbiome. We tracked skin bacterial communities of 62 endangered boreal toads, Anaxyrus boreas , across 18 time points, four probiotic treatments, and two exposures to the lethal fungal pathogen Batrachochytrium dendrobatidis ( Bd ) in captivity, and compared these to 33 s les collected from wild populations at the same life stage. As the hibians in captivity lost the Bd -inhibitory bacteria through time, the proportion of in iduals exposed to Bd that became infected rose from 33% to 100% in subsequent exposures. Inoculations of the Bd -inhibitory probiotic Janthinobacterium lividum resulted in a 40% increase in survival during the second Bd challenge, indicating that the effect of microbiome depletion was reversible by restoring Bd -inhibitory bacteria. Taken together, this study highlights the functional role of ongoing environmental inputs of skin-associated bacteria in mitigating a devastating hibian pathogen, and that long-term captivity decreases this defensive function.