Metabolomic signatures distinguish the impact of formula carbohydrates on disease outcome in a preterm piglet model of NEC

Abstract

BackgroundMajor risk factors for necrotizing enterocolitis (NEC) include premature birth and formula feeding in the context of microbial colonization of the gastrointestinal tract. We previously showed that feeding formula composed of lactose vs. corn syrup solids protects against NEC in preterm pigs; however, the microbial and metabolic effects of these different carbohydrates used in infant formula has not been explored.ObjectiveOur objective was to characterize the effects of lactose- and corn syrup solid-based formulas on the metabolic and microbial profiles of preterm piglets and to determine whether unique metabolomic or microbiome signatures correlate with severity or incidence of NEC.Design/methodsPreterm piglets (103 days gestation) were given total parenteral nutrition (2 days) followed by gradual (5 days) advancement of enteral feeding of formulas matched in nutrient content but containing either lactose (LAC), corn syrup solids (CSS), or 1:1 mix (MIX). Gut contents and mucosal samples were collected and analyzed for microbial profiles by sequencing the V4 region of the 16S rRNA gene. Metabolomic profiles of cecal contents and plasma were analyzed by LC/GC mass spectrometry.ResultsNEC incidence was 14, 50, and 44% in the LAC, MIX, and CSS groups, respectively. The dominant classes of bacteria were Bacilli, Clostridia, and Gammaproteobacteria. The number of observed OTUs was lowest in colon contents of CSS-fed pigs. CSS-based formula was associated with higher Bacilli and lower Clostridium from clusters XIVa and XI in the colon. NEC was associated with decreased Gammaproteobacteria in the stomach and increased Clostridium sensu stricto in the ileum. Plasma from NEC piglets was enriched with metabolites of purine metabolism, aromatic amino acid metabolism, and bile acids. Markers of glycolysis, e.g., lactate, were increased in the cecal contents of CSS-fed pigs and in plasma of pigs which developed NEC.ConclusionsFeeding formula containing lactose is not completely protective against NEC, yet selects for greater microbial richness associated with changes in Bacilli and Clostridium and lower NEC incidence. We conclude that feeding preterm piglets a corn syrup solid vs. lactose-based formula increases the incidence of NEC and produces distinct metabolomic signatures despite modest changes in microbiome profiles.Electronic supplementary materialThe online version of this article (10.1186/s40168-018-0498-0) contains supplementary material, which is available to authorized users.

Interactions between host and gut microbiota in domestic pigs: a review

“…102 Lactose, which is a major sugar present in milk, acts as a prebiotic and can elicit the development of a highly diverse microbiota in the prenatal GIT of growing animals. 103 Although the mechanisms by which lactulose and other prebiotics affect the immune system are not fully understood, it is postulated that they may act indirectly by altering the indigenous microbiota of the GIT and causing changes in microbial metabolite production. 104 Numerous previous studies have identified Lactobacillus as one of the core genera in the GIT of pigs, accounting for approximately 15% of 16S rRNA gene sequences from swine intestinal samples, irrespective of age.…”

Emerging Biomarkers for Prediction and Early Diagnosis of Necrotizing Enterocolitis in the Era of Metabolomics and Proteomics

“…They found that lactose-based formula-fed piglets was associated with a lower prevalence of NEC compared to corn syrup-based-or mixed formula-fed piglets. Plasma from NEC-piglets was enriched with products of purine and aromatic amino acid metabolism and bile acids despite the modest changes observed in the gut microbiome profile (119).…”

“…More recently, Call et al (119) performed microbiome and metabolome analysis in the cecum and plasma, respectively, of a piglet model of NEC exploring the effect of lactose-and corn syrup-based formula. They found that lactose-based formula-fed piglets was associated with a lower prevalence of NEC compared to corn syrup-based-or mixed formula-fed piglets.…”

The Relationship Between Breast Milk Components and the Infant Gut Microbiota

“…Consumption of a lactose-reduced and added-sugar (corn-syrup solids) formula by infants for 6 months slightly increased the diversity (+18%) and Acidaminococcaceae abundance (+0.7 log/mg feces) in feces compared with lactose-containing formula consumption ( 206 ). These effects were not reproduced in a preterm piglet model where diversity was lower in corn-syrup solid formula-fed piglets compared with lactose formula-fed ones ( 207 ).…”