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 quan-tified and a chronology of morphological, histological and ultrastructural events documented. In neonates, a monogastric stomach was present with distinct separation of glandular (an-tral) 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 sym-biotic anaerobic bacilli. Cocci and cocco-bacilli remained at-tached to (or successive populations colonized) the folded for-nical 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 abun-dance of papillae bacilli, and the absence of epithelial damage. suggest that the bacilli are autochthonous, symbiotic and aid the digestive processes oI M. albicaudatus. S. Alr.