Exploring bacterial community composition and immune gene expression of European eel larvae (Anguilla anguilla) in relation to first-feeding diets.

Autor: Bandara KA; Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark.; Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway., Benini E; Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark., Politis SN; Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark., Conceição LEC; SPAROS Lda, Área Empresarial de Marim, Lote C, Olhão, Portugal., Santos A; SPAROS Lda, Área Empresarial de Marim, Lote C, Olhão, Portugal., Sørensen SR; Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark., Tomkiewicz J; Technical University of Denmark, National Institute of Aquatic Resources, Lyngby, Denmark., Vadstein O; Department of Biotechnology and Food Science, NTNU-Norwegian University of Science and Technology, Trondheim, Norway.
Jazyk: angličtina
Zdroj: PloS one [PLoS One] 2023 Jul 27; Vol. 18 (7), pp. e0288734. Date of Electronic Publication: 2023 Jul 27 (Print Publication: 2023).
DOI: 10.1371/journal.pone.0288734
Abstrakt: European eel (Anguilla anguilla) is a commercially important species for fisheries and aquaculture in Europe and the attempt to close the lifecycle in captivity is still at pioneering stage. The first feeding stage of this species is characterized by a critical period between 20 to 24 days post hatch (dph), which is associated with mortalities, indicating the point of no return. We hypothesized that this critical period might also be associated with larvae-bacterial interactions and the larval immune status. To test this, bacterial community composition and expression of immune and stress-related genes of hatchery-produced larvae were explored from the end of endogenous feeding (9 dph) until 28 dph, in response to three experimental first-feeding diets (Diet 1, Diet 2 and Diet 3). Changes in the water bacterial community composition were also followed. Results revealed that the larval stress/repair mechanism was activated during this critical period, marked by an upregulated expression of the hsp90 gene, independent of the diet fed. At the same time, a shift towards a potentially detrimental larval bacterial community was observed in all dietary groups. Here, a significant reduction in evenness of the larval bacterial community was observed, and several amplicon sequence variants belonging to potentially harmful bacterial genera were more abundant. This indicates that detrimental larvae-bacteria interactions were likely involved in the mortality observed. Beyond the critical period, the highest survival was registered for larvae fed Diet 3. Interestingly, genes encoding for pathogen recognition receptor TLR18 and complement component C1QC were upregulated in this group, potentially indicating a higher immunocompetency that facilitated a more successful handling of the harmful bacteria that dominated the bacterial community of larvae on 22 dph, ultimately leading to better survival, compared to the other two groups.
Competing Interests: The authors have declared that no competing interests exist.
(Copyright: © 2023 Bandara et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)
Databáze: MEDLINE
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