[The effects of early and late weaning on the development of the small intestine in the rat: a light-microscopic morphometric study].

UNLABELLED: The small intestine of the rat shows morphologic and enzymatic changes that are associated with the weaning and may be alternated by the early weaning, however, the morphometric criteria have been disregarded. MATERIAL AND METHODS: In this study, the effects of precocious weaning (15 days) and prolonged weaning (32 days), on the size and number of villi; and crypts of small intestine, were analyzed in rats from 16 to 70 days of age. RESULTS: Precocious weaning increased the size of villi, depth and number of crypts in the duodenum and jejunum, while the number of villi decreased. Pups nursed up to 32 days showed no alterations in the analyzed parameters. However, the ileum showed no alterations with the precocious weaning or prolonged. CONCLUSIONS: These data support the concept of an intrinsic biologic program as control of intestinal development while the change of diet seem to have a modifying role in duodenum and jejunum.