Alteration of the Immune Response and the Microbiota of the Skin during a Natural Infection by Vibrio harveyi in European Seabass (Dicentrarchus labrax)

Abstract

Disease outbreaks continue to represent one of the main bottlenecks for the sustainable development of the aquaculture industry. In marine aquaculture, many species from the Vibrio genus are serious opportunistic pathogens responsible for significant losses to producers. In this study, the effects on the immune response and the skin microbiota of European sea bass (Dicentrarchus labrax) were studied after a natural disease outbreak caused by V. harveyi. Data obtained from infected and non-infected fish were studied and compared. Regarding the local immune response (skin mucus) a decrease in the protease activity was observed in infected fish. Meanwhile, at a systemic level, a decrease in protease and lysozyme activity was reported while peroxidase activity showed a significant increase in serum from infected fish. A clear dysbiosis was observed in the skin mucus microbiota of infected fish in comparison with non-infected fish. Moreover, V. harveyi, was identified as a biomarker for the infected group and Rubritalea for healthy fish. This study highlights the importance of characterizing the mucosal surfaces and microbial composition of the skin mucus (as a non-invasive technique) to detect potential disease outbreaks in fish farms.

A strategic model of a host–microbe–microbe system reveals the importance of a joint host–microbe immune response to combat stress-induced gut dysbiosis

“…Infection or other stress factors elicit an acute immune response that will remove resources from other fish metabolic processes, including transcription of host genes usually involved in maintaining gut homeostasis in the host fish (Tort, 2011 ; Nardocci et al, 2014 ; Cámara-Ruiz et al, 2021 ).…”

Skin Culturable Microbiota in Farmed European Seabass (Dicentrarchuslabrax) in Two Aquacultures with and without Antibiotic Use

“…For example, Photobacterium damselae causes photobacteriosis in European seabass with a mortality rate between 60% and 80% [1]. Vibrio species are ubiquitous in aquatic ecosystems, while many Vibrio species are serious opportunistic pathogens causing the most common bacterial diseases [3][4][5]. Control of bacterial pathogens in aquaculture production is routinely achieved by the administration of antibiotics.…”

“…Although studies of the European seabass skin microbiota are not numerous [3,6,7], one study examined the basic diversity of skin microbiomes and gills of farmed seabass and gilthead sea bream [7], but the link to the history of antibiotic therapy remained unclear. Some recent reports have studied the health problems of European seabass in aquaculture [3,6], but only one correlates the abundance of bacteria with problems that are associated with subsequent antibiotic treatment with oxytetracycline [6].…”

“…Although studies of the European seabass skin microbiota are not numerous [3,6,7], one study examined the basic diversity of skin microbiomes and gills of farmed seabass and gilthead sea bream [7], but the link to the history of antibiotic therapy remained unclear. Some recent reports have studied the health problems of European seabass in aquaculture [3,6], but only one correlates the abundance of bacteria with problems that are associated with subsequent antibiotic treatment with oxytetracycline [6]. The abundance of taxa belonging to the non-pathogenic marine group NS3a, and Polaribacter 4 decreased in the skin microbiome of diseased fish with oxytetracycline therapy [6], while the pathogens Pseudomonas and Stenotrophomonas increased significantly.…”

Heat Stress Weakens the Skin Barrier Function in Sturgeon by Decreasing Mucus Secretion and Disrupting the Mucosal Microbiota

“…Specifically, we observed an increase in the abundance of the potential pathogen ( Vibrio , Mesorhizobium , and Phyllobacterium ) under the heat stresses. Vibrio was reported to impair the innate immune system by reducing the mucus protease activity in fish skin ( Guardiola et al, 2014 ; Cámara-Ruiz et al, 2021 ). And, changes in the abundance of intestinal pathogenic bacteria, Mesorhizobium and Vibrio , were associated to pathogen infection ( Yang et al, 2017 ).…”