Domestication of animals imposes strong targeted selection for desired traits but can also result in unintended selection due to new domestic environments. Atlantic salmon (Salmo salmar) was domesticated in the 1970s and has subsequently been selected for faster growth in systematic breeding programmes. More recently, salmon aquaculture has replaced fish oils (FOs) with vegetable oils (VOs) in feed, radically changing the levels of essential long-chain polyunsaturated fatty acids (LC-PUFAs).
View Article and Find Full Text PDFIn salmon farming, the scarcity of fish oil has driven a shift towards the use of plant-based oil from vegetable or seed, leading to fish feed low in long-chain PUFA (LC-PUFA) and cholesterol. Atlantic salmon has the capacity to synthesise both LC-PUFA and cholesterol, but little is known about the regulation of synthesis and how it varies throughout salmon life span. Here, we present a systemic view of lipid metabolism pathways based on lipid analyses and transcriptomic data from salmon fed contrasting diets of plant or fish oil from first feeding.
View Article and Find Full Text PDFBackground: It has been suggested that the high phospholipid (PL) requirement in Atlantic salmon (Salmo salar) fry is due to insufficient intestinal de-novo synthesis causing low lipoprotein (LP) production and reduced transport capacity of dietary lipids. However, in-depth ontogenetic analysis of intestinal PL and LP synthesis with the development of salmon has yet to be performed. Therefore, in this paper we used RNA-Seq technology to investigate the expression of genes involved in PL synthesis and LP formation throughout early developmental stages and associate insufficient expression of synthesis pathways in salmon fry with its higher dietary PL requirement.
View Article and Find Full Text PDFThe development of ectothermic embryos is strongly affected by incubation temperature, and thermal imprinting of body growth and muscle phenotype has been reported in various teleost fishes. The complex epigenetic regulation of muscle development in vertebrates involves DNA methylation of the myogenin promoter. Body growth is a heritable and highly variable trait among fish populations that allows for local adaptations, but also for selective breeding.
View Article and Find Full Text PDFThe infectious salmon anemia virus (ISAv) produces a systemic infection in salmonids, causing large losses in salmon production. However, little is known regarding the mechanisms exerting disease resistance. In this paper, we perform an RNA-seq analysis in Atlantic salmon challenged with ISAv (using individuals coming from families that were highly susceptible or highly resistant to ISAv infection).
View Article and Find Full Text PDFA cohabitation challenge model was developed for use in evaluating the efficacy of vaccines developed against infectious pancreatic necrosis virus (IPNV) in Atlantic salmon (Salmo salar L) using a stepwise approach. The study involved identifying a set of input variables that were optimized before inclusion in the model. Input variables identified included the highly virulent Norwegian Sp strain NVI015-TA encoding the T217A221 motif having the ability to cause >90% mortality and a hazard risk ratio of 490.
View Article and Find Full Text PDFInfectious pancreatic necrosis virus (IPNV) is the cause of one of the most prevalent diseases in farmed Atlantic salmon (Salmo salar). A quantitative trait locus (QTL) has been found to be responsible for most of the genetic variation in resistance to the virus. Here we describe how a linkage disequilibrium-based test for deducing the QTL allele was developed, and how it was used to produce IPN-resistant salmon, leading to a 75% decrease in the number of IPN outbreaks in the salmon farming industry.
View Article and Find Full Text PDFReliability of genomic selection (GS) models was tested in an admixed population of Atlantic salmon, originating from crossing of several wild subpopulations. The models included ordinary genomic BLUP models (GBLUP), using genome-wide SNP markers of varying densities (1-220 k), a genomic identity-by-descent model (IBD-GS), using linkage analysis of sparse genome-wide markers, as well as a classical pedigree-based model. Reliabilities of the models were compared through 5-fold cross-validation.
View Article and Find Full Text PDFAtlantic salmon is susceptible to the salmon louse (Lepeophtheirus salmonis) and the variation in susceptibility within the species can be exploited in selective breeding programs for louse resistant fish. In this study, lice counts were completed on 3000 siblings from 150 families of Atlantic salmon identified as high resistant (HR) and low resistant (LR) families in two independent challenge trials. Skin samples behind the dorsal fin (nearby lice attachment) were collected from ten extreme families (HR or LR) and analyzed by qPCR for the expression of 32 selected genes, including a number of genes involved in T helper cell (Th) mediated immune responses, which have been previously implied to play important roles during salmon louse infections.
View Article and Find Full Text PDFWe have studied stress-induced reversion to virulence of infectious pancreatic necrosis virus (IPNV) in persistently infected Atlantic salmon (Salmo salar L.) fry. Naïve fry were persistently infected with a virulent strain (T(217)A(221) of major structural virus protein 2, VP2) or a low virulent (T(217)T(221)) variant of IPNV.
View Article and Find Full Text PDFInfectious pancreatic necrosis virus (IPNV) is a member of the family Birnaviridae that has been linked to high mortalities in juvenile salmonids and postsmolt stages of Atlantic salmon (Salmo salar L.) after transfer to seawater. IPN vaccines have been available for a long time but their efficacy has been variable.
View Article and Find Full Text PDFBetanodavirus, a small positive-sense bipartite RNA virus notoriously affecting marine aquaculture worldwide has been extensively studied in vitro. However, impending studies in elucidating virus-host interactions have been limiting due to the lack of appropriate animal disease models. Therefore, in this study, we have attempted to successfully establish NNV infection in zebrafish (Danio rerio) showing typical NNV symptoms and which could potentially serve as an in vivo model for studying virus pathogenesis.
View Article and Find Full Text PDFInfectious pancreatic necrosis virus (IPNV), the causative agent of a highly infectious disease in salmonid fish, encodes a small non-structural protein designated VP5. This protein contains Bcl-2 homologous domains and inhibits apoptosis when expressed in cell culture. We have previously reported the generation of three VP5 mutants of IPNV-Sp serotype, using reverse genetics (Santi, N.
View Article and Find Full Text PDFInfectious pancreatic necrosis viruses (IPNVs) exhibit a wide range of virulence in salmonid species. In previous studies, we have shown that the amino acid residues at positions 217 and 221 in VP2 are implicated in virulence. To pinpoint the molecular determinants of virulence in IPNV, we generated recombinant IPNV strains using the cRNA-based reverse-genetics system.
View Article and Find Full Text PDFInfectious pancreatic necrosis virus (IPNV) is the causative agent of infectious pancreatic necrosis (IPN) disease in salmonid fish. Recent studies have revealed variation in virulence between isolates of the Sp serotype, associated with certain residues of the structural protein VP2. The isolates are also highly heterogenic in the coding region of the nonstructural VP5 protein.
View Article and Find Full Text PDFInfectious pancreatic necrosis viruses (IPNVs) belonging to the family Birnaviridae display a high degree of antigenic variability, pathogenicity, and differences in outbreak mortality in salmonid species. To determine if virus isolates of Sp serotype differ in virulence, fry of Atlantic salmon (Salmo salar L.) were challenged with nine different field strains.
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