Project description:Tenacibaculum finnmarkense is a novel Gram-negative, aerobic bacterial strain causing skin ulcers in Atlantic salmon. This is an emerging pathogen, which may cause serious problems to aquaculture. The study was designed to compare the life stages (smolt and posmolt) and to assess effects of environment (fresh and brackis water) on the course of disease and salmon responses to the pathogen.
Project description:Bacterial pathogen Moritella viscosa, the causative agent of winter ulcer, causes heavy losses in Atlantic salmon aquaculture. The study compared responses in salmon reared under normal condition (G100) and fish exposed to hypoxia - 60% saturation of dissolved oxygen - at early life (G60). G60 showed lower survival after challenge. Analyses were performed in the most affected tissues: skin and spleen
Project description:Moritella viscosa is a bacterial pathogen causing winter-ulcer disease in Atlantic salmon. The lesions on affected fish lead to increased mortality, decreased fish welfare, and inferior meat quality in farmed salmon. MicroRNAs (miRNAs) are small non-coding RNAs involved in post-transcriptional regulation by guiding the miRNA induced silencing complex to specific mRNA transcripts (target genes). The goal of this study was to identify miRNAs responding to Moritella viscosa in salmon by investigating miRNA expression in head-kidney and the muscle/skin from lesion sites caused by the pathogen. Protein coding gene expression was investigated by microarray analysis in the same materials.
Project description:Salmon alphavirus (SAV) and Moritella viscosa causing respectively pancreatic disease and winter ulcer are among the most important pathogens threatening Atlantic salmon aquaculture. Fish is protected by vaccination with different rate of success. Here, responses to vaccination were assessed followed with pathogen challenges of vaccinated salmon and saline injected control.
Project description:Due to multi-generation domestication selection, farmed and wild Atlantic salmon diverge genetically, which raises concerns about potential genetic interactions among escaped farmed and wild populations and disrupts local adaptation through introgression. When farmed strains of distant geographic origin are used, it is unknown whether the genetic risks posed by escaped farmed fish will be greater than if more locally derived strains are used. Quantifying gene expression differences among divergent farmed, wild and F1 hybrids under controlled conditions is one of the ways to explore the consequences of hybridization. We compared the transcriptomes of late sac fry of a European (EO) farmed (“StofnFiskur”, Norwegian strain), a North American (NA) farmed (Saint John River, NB strain), a Newfoundland (NF) wild population with EO ancestry, and related F1 hybrids using 44K microarrays. Our findings indicate that the wild population showed greater transcriptome differences from the EO farmed strain than that of the NA farmed strain. We also found the largest differences in global gene expression between the two farmed strains. We detected fewer differentially expressed transcripts between F1 hybrids and domesticated/wild maternal strains. We also found that the differentially expressed genes between cross types over-represented GO terms associated with metabolism, development, growth, immune response, and redox homeostasis processes. These findings suggest that the interbreeding of escaped EO/NA farmed and NF wild population would alter gene transcription, and the consequences of hybridization would be greater from escaped EO farmed than NA farmed salmon, resulting in potential effects on the fitness of wild populations.
Project description:Unintentional use of mold-infested plant-based feed ingredients are sources of mycotoxins in fish feeds. The presence of the emerging mycotoxins ENNB and BEA in Norwegian commercial fish feeds and plant-based feed ingredients has raised concerns regarding the health effects on farmed Atlantic salmon (Salmon salar). Atlantic salmon pre-smolts were exposed to a non-lethal single-dose of BEA and ENNB, and total RNA sequencing of the intestine and liver was carried out to evaluate gut health and identify possible hepatological changes after a single-dose dietary exposure. ENNB and BEA did not give acute toxicity, however ENNB caused the onset of pathways linked to acute intestinal inflammation and BEA exposures caused the onset of hepatic hematological disruption. The prevalence and concentration of ENNB found in today's commercial feed could affect the fish health if consumed over a longer time-period.
