Project description:The salmon louse is an ectoparasitic copepod that causes major economic losses in the aquaculture industry of Atlantic salmon. This host displays a high level of susceptibility to lice which can be accounted for by several factors including stress. In addition, the parasite itself acts as a potent stressor of the host, and outcomes of infection can depend on biotic and abiotic factors that stimulate production of cortisol. Consequently, examination of responses to infection with this parasite, in addition to stress hormone regulation in Atlantic salmon, is vital for better understanding of the host pathogen interaction. Atlantic salmon post smolts were exposed to stress hormone cortisol, lice and their combination. The transcriptomic effects of hormone treatment in salmon skin were significantly greater than lice-infection induced changes. Cortisol stimulated expression of genes involved in metabolism of steroids and amino acids, chaperones, responses to oxidative stress and eicosanoid metabolism and suppressed genes related to antigen presentation, B and T cells, antiviral and inflammatory responses. Cortisol and liceBoth treatments equally down-regulated a large panel of motor proteins that can be important for wound contraction. Cortisol also suppressed multiple genes involved in wound healing, parts of which were activated by the parasite. Down-regulation of collagens and other structural proteins was in parallel with the induction of proteinases that degrade extracellular matrix (MMP9 and MMP13). Cortisol reduced expression of genes encoding proteins involved in formation of various tissue structures, regulators of cell differentiation and growth factors.
Project description:The salmon louse is an ectoparasitic copepod that causes major economic losses in the aquaculture industry of Atlantic salmon. This host displays a high level of susceptibility to lice which can be accounted for by several factors including stress. In addition, the parasite itself acts as a potent stressor of the host, and outcomes of infection can depend on biotic and abiotic factors that stimulate production of cortisol. Consequently, examination of responses to infection with this parasite, in addition to stress hormone regulation in Atlantic salmon, is vital for better understanding of the host pathogen interaction. Atlantic salmon post smolts were exposed to stress hormone cortisol, lice and their combination. The transcriptomic effects of hormone treatment in salmon skin were significantly greater than lice-infection induced changes. Cortisol stimulated expression of genes involved in metabolism of steroids and amino acids, chaperones, responses to oxidative stress and eicosanoid metabolism and suppressed genes related to antigen presentation, B and T cells, antiviral and inflammatory responses. Cortisol and liceBoth treatments equally down-regulated a large panel of motor proteins that can be important for wound contraction. Cortisol also suppressed multiple genes involved in wound healing, parts of which were activated by the parasite. Down-regulation of collagens and other structural proteins was in parallel with the induction of proteinases that degrade extracellular matrix (MMP9 and MMP13). Cortisol reduced expression of genes encoding proteins involved in formation of various tissue structures, regulators of cell differentiation and growth factors. Atlantic salmon post smolts were organised into four experimental groups: lice + cortisol, lice + placebo, no lice + cortisol, no lice + placebo. Infection levels were equal in both treatments upon termination of the experiment. Gene expression changes in skin were assessed with 21 k oligonucleotide microarray and qPCR at the chalimus stage 18 days post infection at 9oC.
Project description:Exposure to environmental contaminants like nonylphenol can disrupt smolt development and may be a contributing factor in salmon population declines. We used GRASP 16K cDNA microarrays to identify genes that are differentially expressed in the liver, gill, hypothalamus, pituitary, and olfactory rosettes of Atlantic salmon smolts treated with nonylphenol compared to control smolts. Nonylphenol treatment was confirmed using physiological assays: nonylphenol-treatment significantly decreased gill Na+,K+-ATPase activity and plasma cortisol and T3 levels.
Project description:This SuperSeries is composed of the following subset Series: GSE26981: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in skin of Atlantic salmon GSE26984: Responses to ectoparasite salmon louse (Lepeophtheirus salmonis) in spleen of Atlantic salmon Refer to individual Series
Project description:Atlantic salmon production in Tasmania (Southern Australia) occurs near the upper limits of the species thermal tolerance. Summer water temperatures can average over 19°C over several weeks and have negative effects on performance and health. Liver tissue exerts important metabolic functions in thermal adaptation. With the aim of identifying the mechanisms underlying liver plasticity in response to chronic elevated temperature in Atlantic salmon, label-free quantitative shotgun proteomics was used to explore quantitative protein changes after 43 days of exposure to elevated temperature. A total of 277 proteins were differentially (adjusted p-value <0.05) expressed between the control (15°C) and elevated (21°C) temperature treatments. As predicted identified by Ingenuity pathway analysis (IPA), transcription and translation mechanisms, protein degradation via the proteasome, and cytoskeletal components were down-regulated at elevated temperature. In contrast, an up-regulated response was predicted identified for NRF2-mediated oxidative stress, endoplasmic reticulum stress, and amino acid degradation. The proteome response was paralleled by reduced fish condition factor and hepato-somatic index at elevated temperature . The present study provides further evidence of the interplay among different cellular machineries in a scenario of heat-induced energy deficit and oxidative stress, and refines present understanding of how Atlantic salmon cope with chronic exposure to temperature near the upper limits of thermal tolerance.
Project description:Recirculation systems (RAS), which reduce water consumption and improve pathogen control are increasingly used in Atlantic salmon aquaculture. Performance and adaptation of fish to new farming environment is actively investigated. Here, responses to crowding stress were compared in salmon reared in two systems (RAS with brackish water and flowthrough with full salinity water) at low and high density.
Project description:ISAV is one of the most dangerous pathogens causing high mortality of farmed Atlantic salmon. In this study, transcriptome responses to the virus were examined in vitro in Atlantic salmon head kidney cells culture (ASK). Poly(I:C), synthetic double-stranded RNA stimulating antiviral responses was used as a positive control.
Project description:This study investigates host-specific gene expression of the Pacific salmon lice, Lepeophtheirus salmonis oncorhynchii, while parasitizing a resistant host (Coho salmon), two susceptible hosts (Atlantic salmon, Sockeye salmon), and a population with-held hosts (starved), over 48 hrs.
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:We investigate the effect of a functional feed for immunostimulation (peptidoglycan extract from bacterial cell wall with nucleotide formulation) on L. salmonis infection levels on Atlantic salmon Salmo salar, and on host and parasite gene expression profiles. Atlantic salmon smolts (~95 g) were fed a control diet, or a low or high dose immunostimulant diet, and then exposed to L. salmonis copepodids in three subsequent exposures. The transcriptome of salmon lice late in the infection attached to either the low dose diet or control diet hosts were compared using a 38K oligonucleotide microarray.
