Histological Study of Esophagus in White Breasted Kingfisher (Halcyon symernensis)

Abstract

Study targeted to clarification the microscopic features of the esophagus structure in (white breasted kingfisher) bird Halcyon smyrnensis, which is primarily piscivorous, through studying of various histological modifications such as relative development of mucosal folds, mucous-secreting glands and musculature have been shown to be correlated with the specific feeding habits of studying bird. Histological study was conducted on ten adult healthy birds during the period from March to May of 2016 in the Animal House of the College of Science / University of Wasit. The results showed that the esophagus kingfisher birds characterized as a thin flexible muscular tube. The most important characteristic of the installation of the esophagus in a bird Kingfisher histologically that the wall of the esophagus found to be composed of only three layers or tunics: mucous, muscular and adventitious arranged from the inside to outside, referring to the absence of tunica submucosa. Microscopic observation of first mucosal layer of esophageal wall showed that it was consists of lamina propria, epithelia and groups of longitudinal folds without discrimination for presence of muscularis mucosae. Mucosal layer of esophagus wall lined by epithelium of non- keratinized stratified squamous epithelium tissue. Lamina propria noticed to compose of numerous mucous esophageal glands. The histological study of esophageal wall also indicated to the absence of submucosa layer because the difficulty to distinguish from the lamina propria. The second tunica tunica a muscularis externa composed of smooth muscle fibers arranged into two secondary layers, inner circular layer and an outer longitudinal layer. In addition to the mentioned tunics it's found a third layer surrounding the muscularis externa consisted of nerve fibers, and fatty cells known adventitia.