Transcriptome profiling of antiviral immune and dietary fatty acid dependent responses of Atlantic salmon macrophage-like cells

A study was conducted to determine if different levels of vegetable and fish oils can alter antiviral responses of salmon macrophage-like cells (MLCs). Atlantic salmon were fed diets containing 7.38% (FO7) or 5.09% (FO5) fish oil. These diets were designed to be relatively low in EPA+DHA (i.e. FO7: 1.41% and FO5: 1%), but near the requirement level, resulting in no significant change in salmon growth. After a 16-week feeding trial, macrophages isolated from fish in these dietary groups were stimulated by a viral mimic (dsRNA: pIC) or PBS (control) for 24 h. A 44K microarray experiment identified the diet-responsive transcripts between dietary treatments and pIC-responsive transcripts within each group. Atlantic salmon were fed for 16 weeks with the FO7 or FO5 diet (4 tanks per diet). Macrophage-like cells were isolated from 2 fish per replicate tank of each dietary group (8 fish from each group in total). The isolated cells from each fish were exposed to PBS (control) or 10 µg ml-1 pIC for 24 h. Samples from 6 individuals (6 PBS and 6 pIC; 12 samples in total per group) in each dietary group were used for microarray experiment. Test samples were labeled with Cy5, whereas the common reference (i.e. a RNA pool of all 24 samples included in microarray experiment) was labeled with Cy3. Each individual test sample was hybridized together with the common reference sample on an array (i.e. 24 arrays in total).