Representative hematoxylin and eosin‐stained cross‐sections of the ileum in the preterm gnotobiotic piglets and a histological score. Representative hematoxylin and eosin‐stained cross‐sections of the ileum in preterm gnotobiotic piglets: 1‐week‐old germ‐free piglets (GF; a,b), piglets colonized with Lactobacillus rhamnosus GG for 1 week (LGG; c,d), 1‐week‐old piglets infected with Salmonella Typhimurium for 24 h (ST; e,f) and piglets colonized with LGG for 1 week and infected with ST for 24 h (LGG+ST; g,h) were compared. Bars represent 500 µm (a,c,e,g) and 100 µm (b,d,f,h). Histological score from the ileum of six piglets per group is depicted (i).