The life histories of a number of fish species such as lamprey, sturgeon, and salmon include prolonged periods of voluntary fasting. These periods, usually coincident with an upstream migration to the rivers and spawning, may last for several months after which the fish either restore feeding or expire. Despite many attempts, it remains unknown what ecological or physiological signals suppress food intake and later, in some fish species, initiate it again. The purpose of this project is to investigate whether fish food intake is linked to metabolic cues, primarily to body adiposity or controlled by coordinated network of hormones such as neuropeptide Y, insulin, leptin and glucagon-like peptide. The expected results will expand the basic knowledge of regulation of appetite and food intake in non-mammalian vertebrates. The practical application of the proposed work may eventually give fish culturists a tool for optimizing feeding regimes and, consequently, food utilization and body composition. This, in turn, will diminish expenses of fish food, prevent as much as possible the body fat dependent phenomenon of early sexual maturation, and at the same time permit production of healthful food sources for humans.
