We checked effects of caper methanolic extracts in rainbow trout.
Cytokine gene expressions were elevated by 0.1 g kg−1 caper extract treatment.
NBT reduction, lysozyme, myeloperoxidase and phagocytic activities were induced.
Growth was enhanced in caper extract fed fish groups.
Caper extract at 0.1 g kg−1 feed proved to be a potential immunostimulant for fish.