New aspects of the esophageal histology of the domestic goat (Capra hircus) and European roe deer (Capreolus capreolus)

Abstract

The present study examines the esophageal wall of animals from two distinct families of the Ruminantia: domestic goats and European roe deer. Five fragments were collected from the entire length of the esophageal wall in five goats and four roe deer and subjected to microscopic and morphometric analyses. All layers of the esophageal wall except the tela submucosa were found to be thicker in the goats. In both species, the esophagus was lined by parakeratinized stratified squamous epithelium, and the tela submucosa was deprived of glands along its entire length. However, the structure of the lamina muscularis mucosae was better developed in goats: it was found to be discontinuous in the proximal part, and then became fused in the cervical part, that is around the most proximal quarter of its length. In contrast, in roe deer, the lamina muscularis mucosae began as sparse, thin muscle bundles at the pharyngeal‐esophageal junction, which thickened and clustered further down the esophagus, but did not fuse. Our findings regarding the microscopic structure of the ruminant esophagus are not fully consistent with the widely‐accepted view and suggest that the histological structure of the esophagus demonstrates interspecies variation within this large suborder. More precisely, species‐specific differences can be seen regarding the presence of esophageal glands and parakeratinized epithelium, and in the organization of the lamina muscularis mucosae.

Comparative anatomical, histometrical, and histochemical study of esophagus between ring-necked parakeet (Psittacula krameri) and black-shouldered kite (Elanus caeruleus)

“…The muscle fibers were oriented longitudinally, the exact orientation of the folds of the mucosa. These results were compatible with the results of Sokolowska (32).…”

Histological and histochemical characteristics of the esophagus in local breed donkey (Equus asinus)

“…Our finding revealed that the tunica mucosa of the esophagus was lined by non-keratinized stratified squamous epithelium with increased thinning at the abdominal part of the esophagus. The non-keratinized esophageal epithelium was recorded in dogs and humans [ 17 ] and guinea pigs [ 21 ], while the equine [ 20 ], goats [ 22 , 23 ], and guinea pig [ 24 ] possess a keratinized type. Our results denoted significant differences in esophageal tunicae thickness along the entire regions of the esophagus.…”

Morphology of the digestive system of the lesser bamboo rat (Cannomys badius)

“…Several insectivorous–omnivorous rodents do not have epithelial keratinisation (Borghesi et al, 2015; Igbokwe & Obinna, 2016; Oliver et al, 2010), whereas the keratinized layer can be found in herbivorous rodents that consume mainly grass and rough plant material (Kotźe et al, 2006; Scopin et al, 2015; Tammam et al, 2017). Like its relative, S. leucodon , C. badius possessed a keratinized epithelium, which may protect the oesophageal mucosa from food abrasion (Scopin et al, 2015; Sokołowska et al, 2021), bacteria invasion (Squier & Kremer, 2001) and gastric juice during regurgitation (if present).…”