Challenging the growing rabbit with a moderately pathogenic E. coli under ad libitum or limited feed intake conditions: impact on digestive physiology, bacterial communities, and on post-weaning growth

The impact of a challenge with moderately pathogenic <em>Escherichia coli</em> O128:C6 on the digestive physiology and gut bacterial community growing rabbits under two feeding programmes was analysed. Upon weaning (28 d old), 180 were allocated to four groups (9 cages 5 per group) for weeks: group C100 non-inoculated fed <em>ad libitum</em>; C70 feed intake limited 70% C100; I100 I70 inoculated libitum</em> or restricted 70%, respectively. At age 31 (D0), orally <em>E. (2.2×108 colony forming units/rabbit). effects inoculation spiked D4, 28% lower growth rate than C100. Limited reinforced inoculation’s growth: had 66% C70. morbidity peaked at 42% between D4 D7 groups, without significant effect level. concentration D5/D6 in caecum groups. Inoculation reduced by 30% (<em>P</em><0.05) villus height/crypt depth villus/crypt area ratios ileum, no associated tenfold increase serum haptoglobin (<em>P</em><0.001) both rabbits. On D5, modified structure ileal (<em>P</em><0.05), but not that caecum. level did affect either diversity community, ileum