Project description:To ensure sustainability of aquaculture, plant-based ingredients are being used in feeds to replace marine-derived products. However, plants contain secondary metabolites which can affect food intake and nutrient utilisation of fish. The application of nutritional stimuli during early development can induce long-term changes in animal physiology. Recently, we successfully used this approach to improve the utilisation of plant-based diets in diploid and triploid Atlantic salmon. In the present study we explored the molecular mechanisms occurring in the liver of salmon when challenged with a plant-based diet in order to determine the metabolic processes affected, and the effect of ploidy. Microarray analysis revealed that nutritional history had a major impact on the expression of genes. Key pathways of intermediary metabolism were up-regulated, including oxidative phosphorylation, pyruvate metabolism, TCA cycle, glycolysis and fatty acid metabolism. Other differentially expressed pathways affected by diet included protein processing in endoplasmic reticulum, RNA transport, endocytosis and purine metabolism. The interaction between diet and ploidy also had an effect on the hepatic transcriptome of salmon. The biological pathways with the highest number of genes affected by this interaction were related to gene transcription and translation, and cell processes such as proliferation, differentiation, communication and membrane trafficking. The present study revealed that nutritional programming induced changes in a large number of metabolic processes in Atlantic salmon, which may be associated with the improved fish performance and nutrient utilisation demonstrated previously. In addition, differences between diploid and triploid salmon were found, supporting recent data that indicate nutritional requirements of triploid salmon may differ from those of their diploid counterparts.
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:The transcriptome response of 12 amoebic gill disease (AGD) affected Atlantic salmon were compared to 6 AGD naive Atlantic salmon at 19 days post infection. The transcriptome response was examined in the gill, liver and anterior kidney.
Project description:The study evaluated effects of dietary cholesterol (CH), taurocholate (TC), choline (CN) and taurine (TA) in Atlantic salmon fed a plant based diet for 77 days. The additives did not affect growth or organ weights of Atlantic salmon, but promoted induction of cholesterol and plant sterol efflux in the intestine, whereas sterol uptake was suppressed. Microarray analyses in the liver indicated decreased cholesterol biosynthesis and enhanced conversion to bile acids. The marked effect of cholesterol on bile acid synthesis suggests that dietary cholesterol can be used to stimulate bile acid synthesis in fish. The study clearly demonstrated how Atlantic salmon adjusted metabolic functions in response to the dietary load of cholesterol, and has expanded our understanding of sterol metabolism and turnover that adds to the knowledge of these processes in fish. Feed supplementation with choline improved lipid absorption and suppressed abnormal accumulation of fat in the gut.
Project description:PD and HSMI are viral diseases that cause heavy damages in Atlantic salmon aquaculture. This study was performed to examine and compare the time-courses of transcriptome responses to the causative agents - salmon alphavirus (SAV) and piscine reovirus (PRV).
Project description:Fish gills are not only the respiratory organ, but also essential for ion-regulation, acid-base control, detoxification, waste excretion and host defense. Multifactorial gill diseases are common in farmed Atlantic salmon, and still poorly understood. Understanding gill pathophysiology is of paramount importance, but the sacrifice of large numbers of experimental animals for this purpose should be avoided. Therefore, in vitro models, such as cell lines, are urgently required to replace fish trials. An Atlantic salmon gill epithelial cell line, ASG-10, was established at the Norwegian Veterinary institute in 2018. This cell line forms a monolayer expressing cytokeratin, e-cadherin and desmosomes, hallmarks of a functional epithelial barrier. To determine the value of ASG-10 for comparative studies of gill functions, the characterization of ASG-10 was taken one step further by performing functional assays and comparing the cell proteome and transcriptome with those of gills from juvenile freshwater Atlantic salmon. The ASG-10 cell line appear to be a homogenous cell line consisting of epithelial cells, which express tight junction proteins. We demonstrated that ASG-10 forms a barrier, both alone and in co-culture with the Atlantic salmon gill fibroblast cell line ASG- 13. ASG-10 cells can phagocytose and express several ATP-binding cassette transport proteins. Additionally, ASG-10 expresses genes involved in biotransformation of xenobiotics and immune responses. Taken together, this study provides an overview of functions that can be studied using ASG-10, which will be an important contribution to in vitro gill epithelial research of Atlantic salmon.
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.
Project description:SALARECON links the Atlantic salmon genome to metabolic fluxes and growth, focusing on energy, amino acid, and nucleotide metabolism.