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

María Cámara-Ruiz,M Carmen Balebona,Isabel M Cerezo,María Ángeles Esteban,Francisco A Guardiola,José María García-Beltrán,Miguel Ángel Moriñigo

doi:10.3390/microorganisms9050964

María Cámara-Ruiz, M Carmen Balebona + Show 5 more

Open Access

https://doi.org/10.3390/microorganisms9050964

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Journal: Microorganisms	Publication Date: Apr 29, 2021
Citations: 23	License type: CC BY 4.0

Affiliation: University of Murcia, Universidad de Málaga

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.

Highlights

Due to the intensification of the aquaculture industry, outbreaks of disease are being increasingly reported and represent a challenge to the expansion of aquaculture production causing significant economic losses to the sector [1]
The presence of bacterial growth from MK and HK samples and ulcers indicated the infection by vibriosis of the animals with symptoms, so the fish were divided into infected and non-infected groups for further analysis
Most infections caused by microorganisms start at or affect the mucosal epithelia of fish [25]

Summary

Introduction

Due to the intensification of the aquaculture industry, outbreaks of disease are being increasingly reported and represent a challenge to the expansion of aquaculture production causing significant economic losses to the sector [1]. The spread of infectious diseases negatively affects varied subsectors related to aquaculture [2]. In marine aquaculture in particular, many Vibrio spp. are serious opportunistic pathogens, which represent the most prevalent bacterial diseases affecting invertebrate and vertebrate species (e.g., finfish, shellfish, and shrimp) [3,4]. Other external changes observed are ulcerative skin lesions, abdominal distension, gill necrosis and darkened skin. Vibrio spp. bacteria usually colonize gills, skin, gut, among other internal organs of the infected host [5]. The infection may become systemic, leading to the mortality of the host [3]

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