Figure 1

Schematic overview of the protocol of the in vivo challenge model. A total of 360 day-old broiler chicks (Ross 308) were randomly assigned to two groups, a control and a challenge group (9 pens per treatment and 20 broilers per pen). All animals were fed a commercial feed and switched to a wheat (57.5%) based diet supplemented with 5% rye on day 12. From day 12 to 18, all animals from the challenge group received daily 10 mg florfenicol and 10 mg enrofloxacin per kg body weight via the drinking water. After the antibiotic treatment, 1 mL of a bacterial cocktail consisting of E. coli, E. faecalis, L. salivarius and L. crispatus, C. perfringens (netB-) and R. gnavus was given daily by oral gavage from day 19 till 21. On day 20, the animals were administered a coccidial suspension consisting of 60 000 oocysts of E. acervulina and 30 000 oocysts of E. maxima. At day 26, the birds were weighed and necropsy was performed on 3 birds per pen. The duodenal loop was sampled for histological examination and content from ileum and colon was collected for protein extraction.