lower gain:feed ratio (0.320 vs. 0.261, P < 0.001) was observed for the RES group. Additionally, an increment of Prevotella sp. was detected in the colonic epimural bacterial community of RES (P = 0.052), whereas Proteobacteria was decreased (P < 0.05). However, the colonic gene expression of toll-like receptors (ΔCq), immunohistochemistry parameters (counts of lymphocytes T, B) and IgA levels (pg IgA/µg total protein) were not modified. In conclusion, the level of nutrition during the suckling phase promoted changes in feed efficiency traits and colonic epimural bacterial community that were not related to the immune response at this level.