The impact of exogenous ω-6 and ω-3 polyunsaturated fatty acids on the induced production of pro- and anti-inflammatory prostaglandins and leukotrienes in Atlantic salmon head kidney cells using a full factorial design and LC–MS/MS

The production of prostaglandins (PGE2, PGE3) and leukotrienes (LTB4, LTB5) in salmon head kidney cell cultures, exposed to different combinations of 20:4ω-6, 20:5ω-3 and 22:6ω-3 polyunsaturated fatty acids (PUFAs), was evaluated by means of a two level factorial design and LC–MS/MS. The method was selective for the pro- and anti-inflammatory analytes and their corresponding stable-isotope labelled internal standards. The regression models were linear over the concentration range 0.5–150 ng/ml with limits of detection of 0.25 ng/ml and quantification of 0.40 ng/ml for the analysed metabolites. The recovery ranged from 78 to 107% for prostaglandins and 73 to 115% for leukotrienes. The analysis of the samples exposed to different combinations of PUFAs revealed that the presence of single ω-3 PUFAs brought an enhancement of the metabolites from the lipooxygenase pathway, specially LTB4, and a reduction of the metabolites from the cyclooxygenase pathway (PGE2 and PGE3), while the two-term interactions generated the opposite effect (high concentration of prostaglandins and low concentrations of leukotrienes). To our knowledge, this is the first implementation of a fully crossed design for investigating the impact of ω-6 and ω-3 PUFAs on the production of eicosanoids not only through their individual but also through their combined effects on Atlantic salmon head kidney cells.