Relative mRNA expression of PAR-2 in the distal intestine of Atlantic salmon. The gene expression was normalized to both elongation factor 1 α and β-actin, and an average normalized ratio for each individual was calculated. The x-axis represents days after introduction to SBM and the y-axis represents the normalized ratio. Relative expression of PAR-2a (A) and PAR-2b (B) in fish fed fishmeal (FM) (n = 6) day 0 or a diet with inclusion of soybean meal (SBM) at day 1 (n = 6), at day 3 (n = 6) and at day 7 (n = 6) days. Relative expression of PAR-2a (C) and PAR-2b (D) of fish fed FM diet and diet with inclusion of SBM after 3 weeks of feeding. Error bars indicate ± S.E.M (standard error of the mean). Different lower case letters denote significant differences (P < 0.05) between the means.