Diet-Dependent Effects of Minimal Enteral Nutrition on Intestinal Function and Necrotizing Enterocolitis in Preterm Pigs

Background: A rapid advance in enteral feeding is associated with necrotizing enterocolitis (NEC) in preterm infants. Therefore, minimal enteral nutrition (MEN) combined with parenteral nutrition (PN) is common clinical practice, but the effects on NEC and intestinal function remain poorly characterized. It was hypothesized that a commonly used MEN feeding volume (16–24 mL/kg/d) prevents NEC and improves intestinal structure, function, and microbiology in preterm pigs. Methods: After preterm birth pigs were stratified into 4 nutrition intervention groups that received the following treatments: (1) PN followed by full enteral formula feeding (OF group, n = 12); (2) PN supplemented with formula MEN and followed by full formula feeding (FF, n = 12); (3) PN plus colostrum MEN followed by formula feeding (CF, n = 12); (4) PN plus colostrum MEN followed by colostrum feeding (CC, n = 10). Results: NEC was absent in the CC group but frequent in the other groups (50%–67%). Compared with other groups, CC pigs showed improved mucosal structures, brush border enzyme activities, and hexose absorption (all P < .05). Relative to formula MEN, colostrum MEN thus improved gut function but did not prevent later formula-induced gut dysfunction and NEC. However, in CF pigs, intestinal lesions were restricted to the colon, compared with all regions in OF and FF pigs, which indicated proximal protection of colostrum MEN. Bacterial composition was not affected by MEN, diet, or NEC outcomes, but bacterial load and concentrations of short-chain fatty acids were reduced in the MEN groups. Conclusion: Colostrum MEN improves intestinal structure, function, and NEC resistance in preterm pigs but does not protect against gut dysfunction and NEC associated with later full enteral formula feeding.