Preliminary evaluation of Lactobacillus rhamnosus strain GG, a potential probiotic in dogs.

Lactobacillus rhamnosus strain GG (LGG) has been studied extensively as a probiotic in humans. However, the ability of an organism to survive passage through the intestinal tract and exert beneficial effects cannot be directly extrapolated between species. This study evaluated the ability of LGG to survive gastrointestinal transit in dogs and assessed whether oral administration of LGG is safe, in order to determine whether studies evaluating the efficacy of LGG in the treatment of canine disease are indicated. Dogs were divided into 5 groups receiving doses of 0 (control group, n = 4), 1 x 10(9) (group 1, n = 8), 1 x 10(10) (group 2, n = 8), 5 x 10(10) (group 3, n = 8) and 5 x 10(11) (group 4, n = 4) colony forming units per day, orally, for 5 days. Lactobacillus rhamnosus GG was detected in the feces of 4/8 dogs in groups 1 and 2, 5/8 dogs in group 3, 4/4 dogs in group 4, and 0/4 dogs in the control group. Fecal colonization was significantly greater in group 4 than in any other group (P < 0.001). Differences between groups 1, 2, and 3 were not significant. No adverse effects were noted. Fecal colonization of LGG in dogs is somewhat variable; however, clinical studies are indicated to evaluate this organism in the treatment and prevention of canine disease.