Location of Endocrine Cells in the Gastrointestinal Tract of White Ibis

For further understanding the digestive physiology of white Ibis,by employment of ABC (streptavidin-peroxidase) immunohistochemical method we studied the distribution of endocrine cells containing 5-hydroxytryptamine (5-HT),met-enkephalin (ENK),substance P (SP),motin and gastric inhibiting polypeptide (GIP) in the gastrointestinal tract of white Ibis (Threskiornis melanocephalus).The results were as follows:5-HT immunoreactive cells were located throughout the gastrointestinal tract with the highest density in the cecum.However,these immunoreactive cells were nearly absent from the stomach.The cells containing ENK and SP were located in the intestine,but they were far sparser than 5-HT cells.Either ENK or SP cells were not congregated throughout the gastrointestinal tract.The cells immunoreactive to motin and GIP were not observed in the gastrointestinal tract of white Ibis.The analysis suggests that the distribution above endocrine cells in the gastrointestinal tract of white Ibis resembles in other bird species,but differs in other vertebrates.