Minimal enteral nutrient requirements for intestinal growth in neonatal piglets: how much is enough?

Background: Parenterally nourished preterm infants commonly receive minimal enteral feedings, the aim being to enhance intestinal function. Whether th is regimen increases intestinal growth has not been established. Objective: Our objective was to determine the minimal enteral nutrient inta kes necessary to stimulate and to normalize neonatal intestinal growth. Methods: Intestinal growth and cell proliferation were quantified in neonat al pigs given equal amounts of an elemental nutrient solution for 7 d. Diff erent groups (n = 5-7 per group) received 0%, 10%, 20%, 40%, 60%, 80%, or 1 00% of total nutrient intake enterally, with the remainder given parenteral ly. Results: In the jejunum, wet weight, protein mass, and villus height were s ignificantly greater at enteral intakes >40%. Stimulation of ileal protein mass required a higher enteral intake (60%). In both segments, abrupt incre ases in DNA mass, crypt depth, ornithine decarboxylase activity, and crypt cells in S-phase occurred between enteral intakes of 40% and 60%. Circulati ng concentrations of glucagon-like peptide-2 and peptide YY, but not gastri n, increased significantly between enteral intakes of 40% and 60% and close ly paralleled indexes of cell proliferation. Conclusions: The minimal enteral nutrient intake necessary to increase muco sal mass was 40% of total nutrient intake, whereas 60% enteral nutrition wa s necessary to sustain normal mucosal proliferation and growth. Our results imply that providing <40% of the total nutrient intake enterally does not have significant intestinal trophic effects.