This study evaluates the effect of probiotic lactic acid bacteria (LAB) on the modulation of the immune system in dogs using two groups of puppies receiving a control diet or a diet with a probiotic Enterococcus faecium (SF68) supplement from weaning to 1 year-old. They evaluate different parameters such as fecal and circulating immunoglobulins and lymphoid cell subsets after the vaccination against canine distemper virus. While there were no differences in the percentage of T-cell subsets, mature B cells were in higher proportion in the puppies that received the probiotic. Therefore, they conclude that specific immune functions in young puppies can be enhanced with dietary probiotic LAB.