Development of the gastric morphology and fornical bacterial/epithelial association in the white-tailed rat Mystromys albicaudatus (Smith 1834)

Abstract

The growth and development of the stomach, gastric epithelia and associated microflora of M. albicaudatus have been quantified and a chronology of morphological, histological and ultrastructural events documented. In neonates, a monogastric stomach was present with distinct separation of glandular (antral) and cornified (fornical) regions. Development of the fornix ventricularis and ‘grenzfalte’ characterized the transitional period and gave rise to the bilocular condition. An early autochthonous microflora of facultative cocci and cocco-bacilli became established. In the infantile phase, fornical papillae developed and provided microhabitats for colonization by symbiotic anaerobic bacilli. Cocci and cocco-bacilli remained attached to (or successive populations colonized) the folded fornical epithelium and pregastric pouch. All common bacteria , were attached to the gastric epithelium by a capsular (slime) layer in palisade formation. The synchrony of events in gastric development (appearance of papillae, ingestion of solid food and the colonization of papillae by bacilli), the numerical abundance of papillae bacilli, and the absence of epithelial damage, suggest that the bacilli are autochthonous, symbiotic and aid the digestive processes of M. albicaudatus.