The effect of peptidoglycan enriched diets on antimicrobial peptide gene expression in rainbow trout (Oncorhynchus mykiss)

► We describe the effect of peptidoglycan (PG) enriched diets on the expression of antimicrobial peptides (AMPs) in rainbow trout. ► The responses to immunostimulation were analysed by real time PCR in skin, gills, gut and liver. ► Different AMPs had different tissue specificity and timing of modulation. ► The positive effect of the diets on AMP expression suggests they could be used to temporarily boost trout immune defences.