However, infiltration of cells in the lamina propria is mainly related to an elevated inflammatory response (Jiang etal.,2000), which would be negative for growth performance indices.
Nofrarı´as etal.(2006) found that increased infiltration of lymphocytes in the lamina propria of ileum and colon was associated to greater lactobacilli counts in piglets fed a diet with a mixture of EO (carvacrol, cinnamaldehyde, and capsicum oleoresin) compared to control.
In any case, effects of intestinal microbiota on immunity are well known (Haghighi et al.,2005) and the increase in IEL and density of cells in the lamina propria observed in our study could be related to the increase in the number of lactobacilli in thegut.