Small Intestinal Disaccharidase Activity and Ileal Villus Height Are Increased in Piglets Consuming Formula Containing Recombinant Human Insulin-Like Growth Factor-I

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Abstract
The effect of orally administered IGF-I on intestinal development was assessed in piglets. Cesarean-derived, colostrum-deprived piglets received formula alone or formula containing 65 nM (500 μg/L) of recombinant human IGF-I. IGF-I intake averaged 200 μg/kg/d. On d 7 and 14 postpartum, piglets were killed, organs were removed and weighed, and tissue and blood samples were collected. The small intestine was divided into 13 segments that were weighed and measured. A sample of each segment was fixed in formalin, and the mucosa was scraped for enzyme analyses. Food intake, body and organ weights, intestinal weight, length, protein, DNA and RNA content did not differ between the treatment groups. Serum IGF-I, IGF-II, and IGF-binding protein profiles and tissue IGF-binding protein mRNA expression were also comparable between the treatment groups. In contrast, intestinal enzymes and villus height were increased by oral IGF-I. Lactase was ≈2-fold higher (p ≤ 0.05) in the jejunum and proximal ileum, and sucrase was ≈50% higher (p ≤ 0.05) in the jejunum of IGF-I-treated animals than in controls. Villus height in the terminal ileum was ≈50% greater in IGF-I-treated animals than in controls(p = 0.03). In conclusion, orally administered IGF-I at 200 μg/kg did not affect whole body or organ growth or serum IGF-I concentrations; however, intestinal disaccharidase activity and ileal villus growth were responsive to orally administered IGF-I, supporting a potential role for milk-borne IGF-I in neonatal intestinal development.