Villas-Bôas, S., Differential expression of novel metabolic and immunological biomarkers in oysters challenged with a virulent strain of OsHV-1, Developmental and Comparative Immunology (2017), doi: 10.1016/j.dci.2017 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. and immunological responses in oyster larvae exposed to OsHV-1 µVar; some of which have 34 not previously been reported in molluscs. Multivariate analyses of entire metabolite profiles 35 were able to separate infected from non-infected larvae. Correlation analysis revealed the 36 presence of major perturbations in the underlying biochemical networks and secondary 37 pathway analysis of functionally-related metabolites identified a number of prospective 38 pathways differentially regulated in virus-exposed larvae. These results provide new insights 39 into the pathogenic mechanisms of OsHV-1 infection in oyster larvae, which may be applied 40 to develop disease mitigation strategies and/or as new phenotypic information for selective 41 breeding programmes aiming to enhance viral resistance. 42

The study aims to evaluate the infection prevalence, virulence gene distribution and antimicrobial resistance of Aeromonas hydrophila associated in diseased outbreaks of cultured freshwater fish in Northern Vietnam. The confirmed A. hydrophila were screened for the presence of the five pitutative-virulence genes including aerolysin (aerA), hemolysin (hlyA), cytotonic enterotoxin (act), heat-labile cytotonic enterotoxin (alt), and heat-stable enterotoxin (ast), and examined the susceptibility to 16 antibiotics. A total of 236 A. hydrophila isolates were recovered and confirmed from 506 diseased fish by phenotypic tests, PCR assays, and gyrB, rpoB sequenced analyses, corresponding to the infection prevalence at 46.4%. A total of 88.9% of A. hydrophila isolates harbored at least one of the tested virulence genes. The genes aerA and act were most frequently found (80.5% and 80.1%, respectively) while the ast gene was absent in all isolates. The resistance to oxacillin, amoxicillin and vancomycin exhibited the highest frequencies (>70%), followed by erythromycin, oxytetracycline, florfenicol, and sulfamethoxazole/trimethoprim (9.3–47.2%). The multiple antibiotic resistance (MAR) index ranged between 0.13–0.88 with 74.7% of the isolates having MAR values higher than 0.2. The results present a warning for aquaculture farmers and managers in preventing the spread of A. hydrophila and minimizing antibiotic resistance of this pathogen in fish farming systems.

23Despite the fact that a successful aquaculture industry for the geoduck Panopea 24 zelandica (Quoy & Gaimard, 1835)

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