microorganisms Article 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 1, Isabel M. Cerezo 2 , Francisco A. Guardiola 1 , José María García-Beltrán 1, M. Carmen Balebona 2 , Miguel Ángel Moriñigo 2 and María Ángeles Esteban 1,* 1 Immunobiology for Aquaculture Group, Department of Cell Biology and Histology, Faculty of Biology, Campus Regional de Excelencia Internacional “Campus Mare Nostrum”, University of Murcia, 30100 Murcia, Spain;
[email protected] (M.C.-R.);
[email protected] (F.A.G.);
[email protected] (J.M.G.-B.) 2 Departamento de Microbiología, Universidad de Málaga, 29071 Málaga, Spain;
[email protected] (I.M.C.);
[email protected] (M.C.B.);
[email protected] (M.Á.M.) * Correspondence:
[email protected] 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 Citation: Cámara-Ruiz, M.; and non-infected fish were studied and compared. Regarding the local immune response (skin Cerezo, I.M.; Guardiola, F.A.; mucus) a decrease in the protease activity was observed in infected fish. Meanwhile, at a systemic García-Beltrán, J.M.; Balebona, M.C.; level, a decrease in protease and lysozyme activity was reported while peroxidase activity showed a Moriñigo, M.Á.; Esteban, M.Á.