Iron Fortification and Inulin Supplementation in Early Infancy: Evaluating the Impact on Gut Microbiome in a Piglet Model.

Background: Prophylactic iron fortification in infant formula effectively prevents iron deficiency anemia. However, the low absorption rate results in excess unabsorbed iron accumulates in colon, where it has been linked to harmful microbiota changes and increased diarrheal incidence. Prebiotic oligosaccharides have shown promise in mitigating these adverse effects, but the role of inulin or synbiotic supplementation with inulin-fermenting lactic acid bacteria in modulating early gut microbiome under iron fortification remains understudied. Objectives: This study used a neonatal pig model to investigate the effects of iron fortification and inulin supplementation, with or without Methods: Twenty-four piglets were stratified and randomly assigned into 1 of the 4 dietary treatments from postnatal day (PD) 2: iron-adequate milk (AI), high-iron milk (HI), high-iron milk with 5% inulin (HIP), or HIP milk with oral gavage of Results: Iron fortification, regardless of inulin supplementation, decreased α-diversity compared with AI. β-Diversity showed clustering of HIP and HIS samples, which were distinct from AI and HI. Although iron fortification had minor impact on microbial composition, inulin supplementation significantly modified microbiome diversity, increasing Conclusions: Inulin supplementation significantly influenced gut microbiome, shifting enterotype from