Coronary artery lesions in atlantic salmon (Salmo salar)

One hundred and fifteen hearts and dorsal aortas were studied in anesthetized or moribund salmon for presence of histological alterations associated with spawning and changing environmental conditions. The control group consisted of 26 fish hatched and raised under experimental and controlled conditions. The study group included 61 prespawners and 23 postspawners. The lesions observed were divided into three grades in increasing order of severity. They consisted of focal or diffuse intimal proliferation of cells resembling smooth muscle cells and frequent alteration of the underlying elastica. The changes were more frequently seen in larger branches of coronary arteries, arterial conus, and atrioventricular sulcus regions. Both the relative incidence and severity of lesions appeared greater in prespawners as compared to postspawners. This study indicates a high incidence of coronary lesions in spawning Atlantic salmon. In addition, the severity of the lesions appeared reduced in postspawners exposed to prolonged starvation. It is suggested that the Atlantc salmon with its exposure to varying environmental conditions may be a useful model to study the epidemiology of coronary artery disease.