In recent years, researchers have c

In recent years, researchers have conducted a lot of researches on the molecular structure, tissue distribution and biological function of avian Ghrelin. Studies have shown that Ghrelin mrna is expressed in the stomach, brain, kidney, liver, pancreas, small intestine, large intestine, lung, muscle, and fallopian tube of birds. Moreover, Ghrelin mrna varies from bird to bird,Kaiya H et al. [41] found that the precursor of chicken Ghrelin was composed of 116 amino acids, the first 24 amino acids at the n-terminal were its signal peptides, and the next 26 amino acids were mature peptides. A-a (arginine-arginine) recognition sites existed at the c-terminal, and the serine 3 of the mature peptide was modified by n-octyl or n-decyl acylation, showing 54% sequence homology with human. Wang J et al. [42] found that African ostrich Ghrelin mature peptide is composed of 28 amino acid residues, and has 73% sequence homology with chicken. Because Ghrelin can regulate the secretion of growth hormone, food intake, gastrointestinal movement, energy metabolism, reproduction, cell proliferation and apoptosis, and ostriches have unique biological characteristics and high economic value, researchers conducted more in-depth studies on ostrich Ghrelin. Wang J et al. [43] used rt-pcr to study the gene expression of Ghrelin in the gastrointestinal tract of African ostriches and found that Ghrelin mrna was expressed in the glandular stomach, muscular stomach, duodenum, ileum, cecum and rectum of African ostriches. In addition, Wang J et al. [44] also studied the distribution of Ghrelin in the cerebellum of African ostriches, and the results showed that Ghrelin was distributed throughout the cerebellum of African ostriches, and the distribution density of Ghrelin in the cerebellum cortex gradually decreased from the molecular layer to the bukhenye cell layer, and the cells were mostly fusiform and irregular polygon. Further studies by Wang J X et al. [45] found that a certain dose of Ghrelin (10 living g/kg) can promote the increase of pepsin content in the small intestine of young ostriches, thereby enhancing their digestion and absorption ability and promoting the growth of young ostriches. When Ghrelin concentration is (100 living g/kg), cellulase activity in cecum and colon increases. Cellulase is a synergistic multi-component enzyme system. High dose of Ghrelin can increase the cellulase activity in cecum and colon, thus improving the digestion ability of young ostriches