Immunomodulating Lactobacilli in Chicken

Abstract

The gastro-intestinal (GI) tract of a chicken starts with the beak, followed by the esophagus and crop, proventriculus (glandular stomach), gizzard (muscular stomach), duodenum, ileum, a pair of blind elongated caeca, colon and ending in the cloaca. The GI-tract consists of a large, single cell layer of epithelial cells surface and a complex microflora that symbiotically interacts with the host. The surface is enlarged by the folds in the mucosal surface which are covered with villi, which in turn are covered by microvilli. For humans the surface of the skin is about 2 m2, while the gut surface is 150-200m2 (about the size of a tennis court). For chickens, these numbers are not available, but the ratio probably is also 100 times the skin surface. Villi are present throughout the small and large intestine. They are longest in the duodenum, but gradually shorten and thicken towards the colon. In the first part of the cloaca they are stumpy and rounded. Villi are present in the caeca also, becoming flattened toward the blind end.