A randomized controlled trial wanted to assess the effect of supplementation intake on the immune functions in cats, of a multivalent vaccine. For this study, a daily supplementation with Enterococcus faecium strain SF68 (NCIMB10415) was provided sin combination with a palatability enhancer on 9 kittens vs the palatability enhancer alone (control). While study specifically evaluated developmental parameters, the amount of CD4 and lymphocytes and SF68 as detected through stools, the results showed and no statistically significant variations on the immune parameters considered, nor in the developmental parameters. The amount of CD4 and lymphocytes, however, was higher in the kittens given the combination of SF68 supplementation with the palatability enhancer.