AJP - Regulatory, Integrative and Comparative Physiology, Vol 261, Issue 4 811-R818, Copyright © 1991 by American Physiological Society
Changes in small intestinal mucosa morphology and cell renewal in suckling, prolonged-suckling, and weaned lambs
D. Attaix and J. C. Meslin
Institut National de la Recherche Agronomique, Centre de Recherches de Clermont-Ferrand-Theix, Ceyrat, France.
No information concerning the effect of weaning on intestinal cell
proliferation is currently available in large species with early intestinal
morphogenesis, a group including most domestic animals and humans. Changes
in intestinal morphology and epithelial cell renewal were investigated in
1-, 5-, and 8-wk-old suckling and 8-wk-old weaned lambs after injection of
[3H]thymidine. In suckling lambs a gradual increase in crypt depth occurred
with age, especially in the proximal intestine, whereas villus height was
significantly reduced in the distal regions. At 8 wk of age weaned and
prolonged-suckling lambs exhibited no significant differences in crypt
depth throughout the intestine and in villus height proximally. However,
weaned lambs had shorter villi in the jejunum and ileum. The highest
enterocyte migration rates (4.4-9.7 microns/h) were observed in 1-wk-old
lambs. In suckling animals, migration rates decreased with age by 60, 51,
and 11% in the duodenum, jejunum, and ileum, respectively. Weaned and
prolonged-suckling 8-wk-old lambs had a similar rate of enterocyte
migration in the ileum. Furthermore, ruminating animals exhibited only
slightly higher migration rates in the duodenum and the jejunum (53 and
15%, respectively). In suckling lambs, epithelial cell renewal required
2.1-4.0, 4.5-6.3, and 4.0-5.3 days at 1, 5, and 8 wk of age, respectively,
whereas labeled cells reached the tips of the villi within 3.0-3.1 days in
weaned animals. These data suggest that the suckling period corresponds to
a gradual and important phase of postnatal intestinal adaptation in the
sheep, a species with early patterns of intestinal cell
replacement.(ABSTRACT TRUNCATED AT 250 WORDS)
