Hyperosmolal formula in neonatal piglets: effects on gastrointestinal hormone concentrations, enteric bacterial titers, and small intestinal histology.

Ingestion of hyperosmolal formula (HOF) by neonatal piglets has been shown to cause significant time-dependent reduction in phase 3 myoelectric activity, which persists in the terminal ileum. To determine whether a single hyperosmolal meal leads to elevated concentrations of gastrointestinal (GI) hormones that inhibit intestinal motility and/or promote bacterial proliferation and disruption of intestinal mucosa, we studied 20 healthy neonatal piglets following feeding with an increased HOF (872 +/- 32 mOsmol/kg, n = 10) and commercial pig milk formula (481 +/- 41 mOsmol/kg, n = 10). Gastrin, secretin, cholecystokinin, and motilin concentrations were determined by radioimmunoassay during fasting and postprandial periods (15, 30, 45, 120, 180, and 240 min). Gastrin concentrations were significantly increased at 15 and 30 min following a hyperosmolal meal (p less than 0.01), but there were no statistical differences in GI hormone concentrations between groups. These transient elevations of gastrin concentrations are associated with significant postprandial reductions in phase 3 small intestinal myoelectric activity (SIMEA) that we have observed. Aerobic bacterial titers were not significantly different between proximal and distal small intestinal segments or between experimental groups, and anaerobic bacteria were seldom recovered. Thus, SIMEA was not sufficiently altered to produce significant bacterial proliferation. Small intestinal histology, assessed by light microscopy, showed normal proximal and distal small intestinal mucosa in 8 of 10 piglets from each group. Therefore, orogastric instillation of a single hyperosmolal feed does not result in intestinal mucosal damage. Further studies are warranted to determine the effects of hyperosmolal feeds when additional risk factors exist in the neonate.