Intestinal Microflora in the Guinea Pig as Observed by Scanning Electron Microscopy. Effect of Fibrous Dietary Supplements

The gastrointestinal ecosystems of weanling guinea pigs fed a purified diet with and without supplements of cabbage, alfalfa and holocellulose were examined by scanning electron microscopy. The diets, which were based on soybean protein, sucrose and wood cellulose, were fed for 28 days and the mucosa and associated microbes were fixed in situ. Bacteria, rods and cocci being the predominant morphological types, were commonly observed on the epithelial surface of the jejunum and ileum and much less frequently in the duodenum. In the cecum, fusiform- and spiral-shaped organisms were the most common types. The fusiforms, which produced unique indentations in the intestinal mucosa, were found in the intestines of the cabbage and alalfa-supplemented guinea pigs but not in those fed the basal diet. There was considerably less mucus on the intestinal epithelium when the cabbage supplement was supplied. Whether promotion of the fusiform population or elimination of the mucus secretion are causally related to the growth stimulating properties of the supplements is not clear, but the results suggest a relationship.