Gross and Histomorphological Assessment of the Oropharynx and Tongue of the Guinea Fowl (Numida Meleagris)

Abstract

The study investigated the morphology of the oropharynx and tongue of the guinea fowl using gross anatomical and histological techniques. The results showed that the mouth and pharynx of the guinea fowl lacked a definite line of demarcation, and so formed a common oropharyngeal cavity. The roof of the oropharynx was formed by the hard palate and the choana. The hard palate was characterized by a broad v-shaped rostral mucosal swelling, a median palatine ridge that bifurcated caudally into left and right lateral palatine ridges, and para-median rows of caudally pointed conical papillae. The tongue of the guinea fowl was located on the floor of the oropharynx, but did not extend to the full limits of the lower beak. The caudal and rostral parts of the tongue were demarcated by a v-shaped row of papillae, the papillary crest. Histologically, the dorsal surface of the tongue was lined by a non-keratinized stratified squamous epithelium that contained intraepithelial taste buds, while the lining on the ventral surface of the tongue was a keratinized stratified squamous epithelium. Other features include a wide sub-epithelial connective tissue layer containing lingual glands, and a core of striated muscles. The lingual glands of the guinea fowl consisted of tubular secretory units made up of mucus-secreting cells. These findings may be important in nutritional and medical management of guinea fowls especially under the intensive system of production. Furthermore, our study has provided a foundation for recognition of pathology in the oropharynx and tongue of the guinea fowl.