Evaluating mucus exudation dynamics through isotopic enrichment and turnover of skin mucus fractions in a marine fish model. Issue 1 (1st December 2020)

• Record Type: Journal Article
• Authors: Ordóñez-Grande, Borja; Fernández-Alacid, Laura; Sanahuja, Ignasi; Sánchez-Nuño, Sergio; Fernández-Borràs, Jaume; Blasco, Josefina; Ibarz, Antoni
• Editors: Cooke, Steven
• Is Part Of: Conservation physiology. Volume 8:Issue 1(2020)
• Publication Date: 2020-12-01
• Subjects: exudation -- isotopic natural abundance -- mucus renewal -- Sparus aurata -- skin mucus fractions; Nature -- Effect of human beings on -- Periodicals; Conservation biology -- Periodicals; 577.05
• DOI: 10.1093/conphys/coaa095
• Languages: English
• ISSNs: 2051-1434

Abstract

Abstract : Isotopic signature of fish skin mucus represents an advantageous non-invasive way to study fish ecology and applied biology. Our results demonstrate that stable isotope enrichment in skin mucus is modified by one meal, and the rate of isotope allocation depends on the soluble or insoluble components of the mucus. Abstract: Fish skin mucus is composed of insoluble components, which form the physical barrier, and soluble components, which are key for interrelationship functions. Mucus is continuously secreted, but rates of production and exudation are still unknown, as are the underlying mechanisms. Using stable isotope analysis, here, we evaluate skin mucus turnover and renewal in gilthead sea bream, separating raw mucus and its soluble and insoluble fractions. Isotopic abundance analysis reveals no differences between mucus and white muscle, thus confirming mucus samples as reliable non-invasive biomarkers. Mucus production was evaluated using a single labelled meal packaged in a gelatine capsule, with both 13 C and 15 N, via a time-course trial. 13 C was gradually allocated to skin mucus fractions over the first 12 h and was significantly (4-fold) higher in the soluble fraction, indicating a higher turnover of soluble mucus components that are continuously produced and supplied. 15 N was also gradually allocated to mucus, indicating incorporation of new proteins containing the labelled dietary amino acids, but with no differences between fractions. When existent mucus was removed, dietary stable isotopes revealed stimulated mucus neoformation dependent on the components. All this is novel knowledge concerning skin mucus dynamics and turnover in fish and could offer interesting non-invasive approaches to the use of skin mucus production in ecological or applied biological studies such as climate change effects, human impact, alterations in trophic networks or habitat degradation, especially of wild-captured species or protected species.