Gross and Microscopic Studies on the Stomach of Domestic Duck (Anas platyrhynchos) and Domestic Pigeon (Columba livia domestica)

Ten adult domestic Mallard ducks and ten adult domestic pigeons of both sexes were used for morphologic and histological study. The proventriculus was the last part of the foregut. It was cone-shaped in pigeon while it was tubular in duck and arose from the esophagus. The ventriculus was biconvex lens in shape. It joined the proventriculus by cardiac sphincter and joined the hind gut by the pyloric sphincter. The thick muscular wall consisted of the crassuscaudodorsalis, crassus- cranioventralis muscles, tenuiscra niodorsalis and caudoventralis. The inner aspect of the ventriculus in both species was lined by a hardened membrane, the cuticula gas- tric. For the histological study, samples from the proventriculus and of the ventriculus were stained routinely with H&E, periodic acid-Schiff(PAS) and Masson’s trichromestain. The mucosal surface of the proventriculus has proventricular papillae over its entire surface with variable density between the two species. The proventriculus and ventriculus in both duck and pigeon have folds of the tunica mucosa lined by columnar epithelium in duck while it is cuboidal in pigeon. Simple tubular glands occupied the lamina propria of both chambers. The ventricular glands were lined by simple cuboidal cells. The proventricular glands were situated between the inner and outer layers of the lamina muscularis mucosae. The tunica submucosa was very thin in the proventricular wall while in the ventriculus, it was not separated from the lamina propria due to the ab- sence of any lamina muscularis mucosae. The tunica muscularis of the proventriculus was formed by a thick inner layer of circular smooth muscle fibres and a thin outer layer of longitudinal fibres. In addition to these layers, oblique muscle fibres formed the most internal layer of the tunica muscularisin the ventriculus.