Development of the Intestinal Villi Associated with the Increased Epithelial Cell Mitosis in Chickens

Abstract

To clarify whether or not an increase of the intestinal villi in size is induced by the increase of the cell proliferation, post-hatching developmental changes of the villous size and the cell mitotic numbers in the crypt were observed in the 1-, 10-and 20-day-old broiler chickens. Newly-hatched chicks were bred in the following nutritional conditions; conventional, high protein-low energy (HL) or low protein-high energy (LH) dietary groups. Besides, in the fasted group for 5 days after hatching morphological alterations of the villi were observed. The intestine of HL group increasing food intake and growing fast had well-developed large villi with marked extrusions of cells at the apex and showed much mitotic division of epithelial cells in the crypt even at 10-day-old. The LH group decreasing food intake and growing slow had small villi and showed few cell mitoses. Denuded apical surfaces were also frequently observed at 20-day-old. In fasted group, shrunk villi and denuded apical surfaces were found. The present findings indicate that the increase of villous size might be induced by the active cell proliferation in the intestinal crypts as well as by the decreased cell loss from the villous tips.