Ghrelin in birds: Its structure, distribution and function

Abstract

Feeding and somatic growth are closely related to each other, and are strictly governed by several endocrine and neuroendocrine systems in animals. Endocrine control of growth is an important subject in poultry industry. Ghrelin is a recently identified, growth hormone (GH)-releasing and feeding-promoting peptide in mammals, and the major source of its release is the stomach. From the comparative endocrinological aspects, ghrelin was considered to be present in avian species. In fact, ghrelin peptide and its cDNA encoding ghrelin precursor have been identified from the chicken proventriculus in 2002, and the presence of the ghrelin molecule has by now been shown in various avian species. In this review, we summarize the recent knowledge of ghrelin structure, distribution and function in birds.