ESOPHAGUS is an important organ of the digestive system and having different layers of tissue in every species of animal plays an important role in digestion. The length and diameter of the esophagus are also different in animals and without on the type of species and the diet it consumes. Because there is not enough information about the histology of Guinea fowl esophagus, this research was done. Eight adult Guinea fowls were the constituted materials of the study. Initially, each bird was humanely killed one by one and subsequently positioned on its back on an autopsy tray. Their abdominal cavity was opened and the esophagus was completely removed. In each animal, sampling was done from four parts of the esophagus, including the upper third, middle third, lower third, and after the crop, and were placed in fixative solution. Then, tissue sections were prepared and stained with routine and specific dyes; Hematoxylin and Eosin, Periodic Acid Shiff, Alcian Blue and Masson’s Trichrome. In Guinea fowl, esophageal epithelium was covered by stratified squamous with numerous folds in the lumen. Also, its thickness was reduced from beginning (457.89μm) to the end (216.76μm). Lamina propria consisted of loose connective tissue with collagen fibers and mucous glands. Muscularis mucosa was made of smooth muscle and its thickness was reduced from beginning (86.76μm) to the end (62.79μm). Tunica muscularis was very thick and was composed of inner thick circular and outer thin longitudinal layers. In histometrical study of esophageal layers, there was significantly different (P ≤.0.05). In conclusion, the esophagus of the Guinea fowl exhibits distinct irregular longitudinal folds in the tunica mucosa that constrict the lumen, similar to observations made in chickens. The lining of its epithelium consists of nonkeratinized stratified squamous cells along with numerous ducts associated with esophageal glands. Interestingly, the thickness of the epithelium decreases from the beginning of the esophagus, measuring 457.89μm, to the end, which is only 216.76μm. Additionally, the thickness of the muscularis mucosa shows variation, being thinner at the start of the esophagus and just after the crop in comparison to the other

Keywords