The effects of total parenteral nutrition on gastrointestinal growth and development.

Total parenteral nutrition (TPN) is vital for the nutritional support of infants with disorders of the gastrointestinal tract that prevent adequate enteral intake. Studies in adult rodents maintained on TPN have demonstrated intestinal atrophy and decreased activity of the brush border enzymes of the small bowel mucosa. We studied the effects of TPN during the phase of rapid intestinal growth and development in piglets. Matched groups of three 6-week-old weaned piglet littermates received a glucose (45 g/kg/d), amino acid (8 g/kg/d), and fat (2.5 g/kg/d) solution intravenously (IV) or by gastrostomy (GF), or were given hog chow (Chow) at an equivalent caloric value for three weeks. No differences were noted in the mean weight gain (13-15 g/kg/d), total serum protein (4.5-4.8 g/dL), BUN (9-12 mg/dL), or Hct (25% to 30%). The IV and GF animals, compared to the Chow animals, had decreased growth of the stomach, small bowel, and pancreas with decreased small bowel mucosal disaccharidase activity. The IV group, compared to Day 0 animal measurements, had decreased small bowel length and weight and pancreatic weight. Histology of the proximal small bowel mucosa in the IV animals showed decreased mucosal depth, villus height, crypt depth, and epithelial cell number from the crypt base to the midvillus. These findings suggest that stomach, small bowel, and pancreatic growth are dependent on the route of administration and/or the composition of the diet, the small bowel mucosa and the pancreas atrophies in young piglets maintained on TPN, the activity of some intestinal brush border disaccharidases are decreased in the small bowel in piglets maintained on either an intravenous or an intragastric infusion of a TPN solution.