Minimal Enteral Feedings Suppress Intestinal Mucosal Growth That Is Not Reversed by Glutamine Supplementation in Neonatal Dogs |[bull]| 1545

The combination of parenteral nutrition and minimal enteral feedings (MEF), i.e. 10-20% of daily fluid intake, is commonly used in neonates to reduce the risk of necrotizing enterocolitis. We have previously shown that MEF enhances maturation of intestinal motor function but not gut growth in parenterally fed neonatal dogs (Pediatr Res 39:125A). Although glutamine has been shown in some studies to prevent mucosal atrophy, it has not been established whether its addition to MEF can enhance gut growth in healthy gut. Our hypothesis was that MEF+Glutamine would enhance gut growth as well as maturation of motor function. Methods: We placed central venous catheters in 31 newborn puppies from 6 litters who were given 200 ml/kg/d parenterally. Puppies were then randomly assigned to 4 groups: No enteral feeds(NPO), MEF(20 ml/kg/d), MEF+Glutamine and MEF+Glutamate (to control for protein intake). Enteral feeds were comprised of a pooled mixture (1:1) of canine and human milk enriched with either glutamine or glutamate at 0.4g/10 ml (800 mg/kg/d). Pups were gavage fed 5 times daily for 4 days and the volume of parenteral nutrition was reduced in the 3 MEF groups by the volume of enteral feedings given. Fluid intake was adjusted daily for weight gain. After 4 days, motor activity was then recorded for 2 hr and blood samples drawn for motilin and gastrin concentrations. Abdominal organs were then harvested for physical/biochemical assessment of growth. Results: There were no differences among the 4 groups with respect to overall weight gain or weight of stomach, intestine, liver or intestinal length. The DNA content (mg/kg body wt.) in duodenum and the protein contents of the duodenum, jejunum and ileum of the fed groups were all significantly lower compared to those seen in the NPO group(ANOVA/Fishers; all p<0.05). There were no significant differences in plasma gastrin or motilin concentrations. The duration of migrating motor activity was significantly higher in the Glutamine supplemented group compared to the Glutamate or NPO groups but not from MEFgroup. Conclusion: Although enteral glutamine does not augment maturation of motor function beyond that induced by MEF, enteral glutamate appears to suppress it. Minimal enteral feedings with or without glutamine or glutamate supplementation does not cause body or organ weight changes; indeed, MEF decreased mucosal growth. We speculate that enteral feeds may challenge the intestinal mucosa by causing local inflammatory responses which prevents growth.