Indeed, reduced bulbar compliance in trout by parasite infection or cholecystokinin increases cardiac afterload leading to ventricular hypertrophy and fibrosis [39,69] and Clark & Rodnick [25] showed that increased cardiac afterload in fish induced ventricular hypertrophy via an increase in myocyte cross-sectional area, mirroring mammalian remodelling [25,57,70]. This evidence concerns the gene CCK and parasitic infectious disease.