Effect of age on epithelial cell migration in small intestine of chickens.

Villous length, crypt depth, epithelial cell migration rate, and replacement time were studied by autoradiography of histologic sections of small intestine from normal chickens exposed to tritiated thymidine (3-H-TdR). The results indicated that villi and crypts elongate, and epithelial cell migration accelerates between 1 day and 6 months of age. Epithelial replacement time seemed to increase with age of the chickens. Replacement was nearly complete in the 1-day-old group of chickens 5 days after thymidine exposure. In contrast, at this same time, replacement was only approximately 75 and 50% complete in the 3-week-old and 6-month-old groups of chickens, respectively.