Objectives and study: Microbiota is known to be positively influenced by breastfeeding. Differencesin the quality and structure of dietary lipids between maternal milk and infant formulas may contributeto microbiota modification. Incorporation of milk fat in infant formulas is a promising way to get closerto the composition and structure of human milk fat globules. However, little is known on theconsequences of such addition on gut microbiota and physiology.Methods: Two formulas were processed containing either vegetable lipids (VL) or a mixture of milkand vegetable lipids (ML) including milk fat globule membrane fragments. Formulas wereautomatically distributed to newborn piglets until 28 days of age. Feces and ileal tissue were sampledat slaughter at 28 days. The bacterial composition expressed as the percentage of assignedsequences at each taxonomic level as well as Shannon diversity and Chao richness indices weredetermined. Weight and mucosal density of empty ileum were measured. Ileal barrier function wasevaluated ex vivo using Ussing chamber. Mononuclear immune cells isolated from mesenteric lymphnodes were cultured to evaluate their secretory cytokine profiles.Results: No difference in bacterial diversity indices was observed between VL and ML groups. Theanalysis of dominant phyla revealed a greater proportion of Proteobacteria in ML than in VL microbiota(13.4 % vs. 5.4 % respectively) at the expense of Firmicutes that were reduced L (62.1 % vs. 74.5 %respectively). No difference in sub-dominant phyla was significant. Abundance of five bacterial familiesand genus was modulated with the dietary treatment. Increased Porphyromonadaceae family(Bacteroides phylum) consisted of a higher proportion of Parabacteroides, and increasedEnterobacteriaceae family (Proteobacteria phylum) consisted of greater number ofEscherichia/Shigella and Klebsiella genus in feces of ML piglets compared to VL piglets. In addition,Clostridiales Family XIII and Veillonellaceae explained the decrease of Firmicutes in ML piglets.Interestingly, significant correlations between microbiota composition and gut physiological andimmunological parameters were highlighted. Relative abundance of Klebsiella and Parabacteroideswas negatively correlated with ileal pH (rho value = -0.56, P