1Department of Physiology and Pharmacology, Faculty of Veterinary Science, Science and Research Branch, Islamic Azad University, Tehran, Iran.
2Faculty of Agriculture, Islamic Azad University Karaj Branch, Karaj, Iran.
Forty eight one-day old male vistar rats were kept in 3 groups on isocaloric diet, with normal (control), 1.5 percent higher or lower raw protein (T1) and (T2). After 31 d these were sacrificed and samples were taken from proximal and distal duodenum, jejunum and ileum for morphological and enzymological investigations. All villous parameters (villous height, villous width and crypt depth) increased (P<0.05) in T1 and decreased in T2 in most parts of the small intestine compared with the control group. In T1 group leaf-like and tongue like villi increased (P<0.05) but bridge like villi decreased. In T2 group the results were reversed. Brush border total leucine amino peptidase and lipase activity increased in T1 and decreased in T2. Therefore, it seems that protein content of the food can change shape and size of the villi and enzyme activity and, therefore, will lead to changes in the absorption capacity of the small intestinal mucosa.
Protein, villi, villous height, crypt depth, villous width, lipase, leucineaminopeptidase
