Neonatal Abx administration causes ileal pathophysiology without causing intestinal inflammation in adulthood. Ussing chamber studies assessed (A) short circuit current [Isc], (B) conductance (G) and (C) FITC flux in the ileum (N = 11–16). (D) Expression of immune-related genes (cytokines, pattern recognition receptors) in the ileum by qPCR (N = 8). Females denoted as light grey circles, and males as dark grey squares. Students T-test, *p < 0.05, **p < 0.01.