Somatostatin inhibits growth of rainbow trout

Abstract

Implantation of rainbow trout Oncorhynchus mykiss with somatostatin‐14 (SS‐14) for 20 days resulted in reduced food conversion as well as significant growth retardation compared to controls. Relative growth as mass was reduced by 20%, whereas relative growth by length was reduced by 45%. A single intraperitoneal injection of SS‐14 reduced plasma levels of growth hormone (GH), insulin‐like growth factor‐1 (IGF‐I) and insulin. SS‐14 injection also reduced [ 35 S]‐sulphate incorporation into gill cartilage compared to saline‐injected fish. In addition, in vitro incubation of gill cartilage with SS‐14 reduced [ 35 S]‐sulphate incorporation in a doserelated manner. These results indicate that SS‐14 inhibits growth of rainbow trout and suggests that SS‐14, in addition to influencing GH, may play an extra‐pituitary role in the modulation of the GH‐IGF‐I axis.