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Tadeu AD, Duarte J, Trindade D, Costa P, Venâncio C, Lopes I, Oliveira V, Gomes NCM, Almeida A, Pereira C. Bacteriophages to control Vibrio alginolyticus in live feeds prior to their administration in larviculture. J Appl Microbiol 2024; 135:lxae115. [PMID: 38710582 DOI: 10.1093/jambio/lxae115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/16/2024] [Accepted: 05/04/2024] [Indexed: 05/08/2024]
Abstract
AIMS This study aimed to evaluate the efficiency of two phages [VB_VaC_TDDLMA (phage TDD) and VB_VaC_SRILMA (phage SRI)] alone and in a cocktail to control Vibrio alginolyticus in brine shrimp before their administration in larviculture. METHODS AND RESULTS Phages were isolated from seawater samples and characterized by host spectrum, growth parameters, adsorption rate, genomic analysis, and inactivation efficiency. Both phages belong to the Caudoviricetes class and lack known virulence or antibiotic-resistance genes. They exhibit specificity, infecting only their host, V. alginolyticus CECT 521. Preliminary experiments in a culture medium showed that phage TDD (reduction of 5.8 log CFU ml-1 after 10 h) outperformed phage SRI (reduction of 4.6 log CFU ml-1 after 6 h) and the cocktail TDD/SRI (reduction of 5.2 log CFU ml-1 after 8 h). In artificial marine water experiments with Artemia franciscana, both single phage suspensions and the phage cocktail, effectively inactivated V. alginolyticus in culture water (reduction of 4.3, 2.1, and 1.9 log CFU ml-1 for phages TDD, SRI, and the phage cocktail, respectively, after 12 h) and in A. franciscana (reduction of 51.6%, 87.3%, and 85.3% for phages TDD, SRI, and the phage cocktail, respectively, after 24 h). The two phages and the phage cocktail did not affect A. franciscana natural microbiota or other Vibrio species in the brine shrimp. CONCLUSIONS The results suggest that phages can safely and effectively control V. alginolyticus in A. franciscana prior to its administration in larviculture.
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Affiliation(s)
- Amanda Dias Tadeu
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - João Duarte
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - David Trindade
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Pedro Costa
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Cátia Venâncio
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Isabel Lopes
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Vanessa Oliveira
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Newton C M Gomes
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Adelaide Almeida
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
| | - Carla Pereira
- Department of Biology and CESAM, University of Aveiro, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal
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Leiva-Rebollo R, Gémez-Mata J, Castro D, Borrego JJ, Labella AM. Immune response of DNA vaccinated-gilthead seabream ( Sparus aurata) against LCDV-Sa infection: relevance of the inflammatory process. Front Immunol 2023; 14:1209926. [PMID: 37346045 PMCID: PMC10279854 DOI: 10.3389/fimmu.2023.1209926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Accepted: 05/22/2023] [Indexed: 06/23/2023] Open
Abstract
Lymphocystis disease is one of the main viral pathologies affecting cultured gilthead seabream (Sparus aurata) in the Mediterranean region. Recently, we have developed a DNA vaccine based on the major capsid protein (MCP) of the Lymphocystis disease virus 3 (LCDV-Sa). The immune response triggered by either LCDV-Sa infection or vaccination have been previously studied and seem to be highly related to the modulation of the inflammatory and the IFN response. However, a comprehensive evaluation of immune-related gene expression in vaccinated fish after viral infection to identify immunogenes involved in vaccine-induced protection have not been carried out to date. The present study aimed to fulfill this objective by analyzing samples of head-kidney, spleen, intestine, and caudal fin from fish using an OpenArray® platform containing targets related to the immune response of gilthead seabream. The results obtained showed an increase of deregulated genes in the hematopoietic organs between vaccinated and non-vaccinated fish. However, in the intestine and fin, the results showed the opposite trend. The global effect of fish vaccination was a significant decrease (p<0.05) of viral replication in groups of fish previously vaccinated, and the expression of the following immune genes related to viral recognition (tlr9), humoral and cellular response (rag1 and cd48), inflammation (csf1r, elam, il1β, and il6), antiviral response (isg15, mx1, mx2, mx3), cell-mediated cytotoxicity (nccrp1), and apoptosis (prf1). The exclusive modulation of the immune response provoked by the vaccination seems to control the progression of the infection in the experimentally challenged gilthead seabream.
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Affiliation(s)
| | | | | | | | - Alejandro M. Labella
- Department of Microbiology, Faculty of Sciences, University of Malaga, Malaga, Spain
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Hartman LM, Blackall LL, van Oppen MJH. Antibiotics reduce bacterial load in Exaiptasia diaphana, but biofilms hinder its development as a gnotobiotic coral model. Access Microbiol 2022; 4:000314. [PMID: 35252752 PMCID: PMC8895603 DOI: 10.1099/acmi.0.000314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 12/07/2021] [Indexed: 12/02/2022] Open
Abstract
Coral reefs are declining due to anthropogenic disturbances, including climate change. Therefore, improving our understanding of coral ecosystems is vital, and the influence of bacteria on coral health has attracted particular interest. However, a gnotobiotic coral model that could enhance studies of coral–bacteria interactions is absent. To address this gap, we tested the ability of treatment with seven antibiotics for 3 weeks to deplete bacteria in Exaiptasia diaphana, a sea anemone widely used as a coral model. Digital droplet PCR (ddPCR) targeting anemone Ef1-α and bacterial 16S rRNA genes was used to quantify bacterial load, which was found to decrease six-fold. However, metabarcoding of bacterial 16S rRNA genes showed that alpha and beta diversity of the anemone-associated bacterial communities increased significantly. Therefore, gnotobiotic E. diaphana with simplified, uniform bacterial communities were not generated, with biofilm formation in the culture vessels most likely impeding efforts to eliminate bacteria. Despite this outcome, our work will inform future efforts to create a much needed gnotobiotic coral model.
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Affiliation(s)
- Leon M. Hartman
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
- Swinburne University of Technology, Hawthorn, VIC, Australia
- Monash University, Clayton, VIC, Australia
| | - Linda L. Blackall
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Madeleine J. H. van Oppen
- Australian Institute of Marine Science, Townsville, QLD, Australia
- School of BioSciences, The University of Melbourne, Melbourne, VIC, Australia
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Initial Evidence That Gilthead Seabream ( Sparus aurata L.) Is a Host for Lymphocystis Disease Virus Genotype I. Animals (Basel) 2021; 11:ani11113032. [PMID: 34827765 PMCID: PMC8614504 DOI: 10.3390/ani11113032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 10/12/2021] [Accepted: 10/19/2021] [Indexed: 11/29/2022] Open
Abstract
Simple Summary Nodular lesions were observed on the skin and fins of 95% of one and a half million juvenile gilthead seabreams cultured in Egypt, shortly after importation from Europe. We undertook a study to describe the clinical disease course, identify the causative agent, and investigate the origin of the causative agent. Preliminary diagnosis based on gross lesions and postmortem examination suggested lymphocystis disease caused by lymphocystis disease virus, Lymphocystivirus, Iridoviridae. Histopathological and ultrastructural pictures were typical of lymphocystis disease virus infections. Polymerase Chain Reaction followed by sequencing and phylogenetic analysis of the major capsid protein gene demonstrated the presence of lymphocystis disease virus genotype I, originally associated with lymphocystis disease in Northern European countries, with 99.7% and 100% nucleotide and deduced amino acid identity values, respectively. Lymphocystis disease virus genotype I has never been reported in this species or in the region. Regardless of whether it has maintained a previously undetected state of endemicity in Egypt or was introduced through importation or contamination of ship ballast water, the findings of this study add to existing knowledge about the lymphocystis disease’s ecology, and lymphocystis disease virus genotypes and their host range. Abstract Marine and brackish water aquacultures are rapidly expanding in the Mediterranean basin. In this context, Egypt recently received a shipment of a 1.5 million juvenile gilthead seabream (Sparus aurata L.) from European Mediterranean facility. Within a few weeks of their arrival, 95% of the imported fish developed nodules on their skin and fins that lasted for several months. This study was undertaken to describe the clinical disease course, to identify the causative agent, and to investigate its origin. Preliminary diagnosis based on gross lesions and postmortem examination suggested lymphocystis disease (LCD), caused by the lymphocystis disease virus (LCDV; genus Lymphocystivirus, family Iridoviridae). Histopathological and ultrastructural features were typical of LCDV infections. PCR followed by sequencing and phylogenetic analysis of a 306-bp fragment of the major capsid protein (MCP) gene demonstrated the presence of LCDV genotype I, originally associated with LCD in Northern European countries, with 99.7% and 100% nucleotide and deduced amino acid identity values, respectively. LCDV genotype I has neither been reported in this species nor in the region. Regardless of the source of infection, findings of this study add to existing knowledge about the ecology of LCDV genotype I and its host range.
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Leiva-Rebollo R, Castro D, Moreno P, Borrego JJ, Labella AM. Evaluation of Gilthead Seabream ( Sparus aurata) Immune Response after LCDV-Sa DNA Vaccination. Animals (Basel) 2021; 11:ani11061613. [PMID: 34072482 PMCID: PMC8228267 DOI: 10.3390/ani11061613] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 02/07/2023] Open
Abstract
Simple Summary Lymphocystis disease is the main viral pathology in gilthead seabream aquaculture. Currently, there are no treatments or vaccines to control this disease, thus our main goal was to construct a DNA vaccine that can be used in the future to stop the spread of this pathology in sea farms. The vaccine consisted of a plasmid DNA that contains a known viral gene. Once it was established that the vaccine drives the expression of the antigenic viral protein in fish, vaccination experiments were conducted to determine if the vaccinated fish become protected against the viral infection. In addition, the immune response triggered by the vaccine was also evaluated in order to understand the mechanisms underlying such protection. The obtained results showed that in vaccinated fish an activation of several genes relating to both the inflammatory process and the mucosal immunity were produced, as well as specific anti-viral antibodies. Although limited, our results deserve further investigation to assess the efficacy of the vaccine in bigger fish populations and to confirm the mode of action of the vaccine. Abstract Lymphocystis disease is the main viral pathology reported in gilthead seabream. Its etiological agent is Lymphocystis disease virus 3 (LCDV-Sa), genus Lymphocystivirus, family Iridoviridae. There are no effective treatments or vaccines for LCDV control, thus the main aim of this study was to develop a DNA vaccine, and to evaluate both the protection conferred against LCDV-Sa infection and the immune response in vaccinated fish. The vaccine was constructed by cloning the mcp gene (ORF LCDVSa062R) into pcDNA3.1/NT-GFP-TOPO. Two independent vaccination trials were conducted. In the first one, 5–7 g fish were intramuscularly injected with the vaccine (pcDNA-MCP) or the empty-plasmid, and the distribution and expression of the vaccine was investigated. Furthermore, vaccinated fish were challenged with LCDV-Sa in order to access the protective capacity of the vaccine. In the second trial, 70–100 g fish were vaccinated as specified, and the immune response was evaluated analyzing the expression of 23 immune-related genes and the production of specific antibodies. The results showed that the vaccine triggers an immune response characterized by the overexpression of genes relating to the inflammatory process, but not the innate antiviral immunity relating to type I IFN (interferon), and also induces the production of specific neutralizing antibodies, which could explain the protection against LCDV-Sa in vaccinated fish.
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Vázquez-Salgado L, Olveira JG, Dopazo CP, Bandín I. Role of rotifer ( Brachionus plicatilis) and Artemia ( Artemia salina) nauplii in the horizontal transmission of a natural nervous necrosis virus (NNV) reassortant strain to Senegalese sole ( Solea senegalensis) larvae. Vet Q 2021; 40:205-214. [PMID: 32813983 PMCID: PMC7734120 DOI: 10.1080/01652176.2020.1810357] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Marine invertebrates are provided as a first feed for marine fish larvae because of their strict nutritional requirements, despite also being a potential source of infectious agents. AIM To assess horizontal transmission of a nervous necrosis virus reassortant strain (NNV) to sole larvae via Artemia and rotifers. MATERIALS AND METHODS Rotifer (Brachionus plicatilis) and Artemia (Artemia salina) nauplii cultures were bath infected with a reassortant (RGNNV/SJNNV) NNV strain isolated from gilthead sea bream and viral internalisation was confirmed by IFA. Senegalese sole (Solea senegalensis) larvae were fed on infected Artemia and disease signs and mortality were recorded. In addition, NNV viability was checked in cultures of either unfed invertebrates or invertebrates fed on phytoplankton and in the supernatant of microalgae cultures. All samples were tested by RT-qPCR and inoculation in cell culture. RESULTS Both rotifers and Artemia internalised NNV. Experimental transmission to sole larvae was achieved using infected Artemia and subsequently 60% mortality was recorded. At 24 h post-infection, orally infected individuals contained 9.34 × 104 copies of viral RNA, whereas the bath infection yielded 2.05 × 106 RNA copies larvae-1. Viral presence in both invertebrates was detected up to 8 days post infection but viral load decreased over time. Feeding with microalgae decreased viral detection even more and microalgae supernatants were demonstrated to significantly affect NNV viability. CONCLUSIONS Our results demonstrate that both invertebrates can bioaccumulate NNV and that Senegalese sole larvae fed on infected Artemia might develop viral encephalopathy and retinopathy and high mortality.
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Affiliation(s)
- L Vázquez-Salgado
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - J G Olveira
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - C P Dopazo
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
| | - I Bandín
- Instituto de Acuicultura, Departamento de Microbiología y Parasitología, Universidade de Santiago de Compostela, Santiago de Compostela, Spain
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Abstract
The objective of this study was to conduct field experiments comparing formulated (extruded pellets (E.P)) and raw-fish (moist pellets (M.P)) feeds at two flounder aquaculture farms for six months to obtain the basic data necessary for improving aquafarmers’ awareness of feed-quality issues and firmly establish and expand the use of formulated feed. According to the results, the M.P group was higher in weight gain, feed efficiency ratio, protein efficiency ratio, and specific growth rate and lower in mortality rate than the E.P group. All cases of mortality were caused by six kinds of disease, four of which (Vibrio sp., Edwardsiella sp., Streptococcus sp., and Scuticociliates) were common to the two groups, whereas Lymphocystis arose only in the M.P group and abdominal inflation only in the E.P group at both farms. As for mortality in the present experiment, the numbers were 1047 at Da-Hae farm and 1167 at Global farm, with more fish dying in the E.P tanks than in the M.P tanks. By multiplying the number of deaths by selling price, the economic losses were $9650 and $10,756, respectively. Therefore, it should be considered an urgent priority to develop flounder-exclusive formulated feed for improved digestion and absorption rate and also to establish a water-quality-improvement management plan.
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