Oral Insulin Stimulates Intestinal Department and Enzyme Maturation in Newborn Pigs

The effects of oral insulin on intestinal tissue growth and brush border enzyme activitiesin newborn pigs were examined in this study. Newborn unsuckled pigs were bottle-fed for3 days with artificial milk(M), milk supplemented with 60mIUmL-1 of insulin(IM) orhydrolyzed milk(HM). Compared with newborn unsuckled pigs, piglets bottle-fed for 3 daysall gained in intestinal weight and length significantly despite a mild loss in bodyweight during the experimental period. The activities of lactase and alkaline phosphatase(AKP) in the small intestinal mucosa declined markedly in pigs fed with M, but theactivity of maltase increased significantly during the experimental period. Dietaryprotein pre-hydrolysis had no significant effect on intestinal tissue mass or length,but it moderated the decline of intestinal lactase and AKP activities. Dietarysupplementation of insulin significantly increased mucosal protein content and brushborder activities of lactase, maltase, AKP and aminopeptidase(AP)in the small intestine.The effect of insulin treatment was particularly obvious at the distal region of the smallintestine. These results demonstrate that oral insulin can stimulate intestinal digestiveenzyme activities in newborn pigs. The finding supports the hypothesis that milk-borneinsulin plays a role in regulating postnatal gut development in the suckling young.