Abstract
This study reports a new therapeutic approach for canine giardiasis, the most common intestinal protozoan infection caused by Giardia intestinalis. It is based on the use of the probiotic strain Lactobacillus johnsonii CNCM I-4884 and, in particular, its bile salt hydrolase enzymatic activities. Clinical trials in dogs demonstrated that daily administration of L. johnsonii CNCM I-4884 significantly reduced Giardia cyst shedding after 14 days. These results highlight the potential of this probiotic as a promising alternative to antimicrobials, such as nitroimidazoles or benzimidazoles, for the treatment of giardiasis in dogs. Moreover, they provide a novel approach for the veterinary industry to develop innovative products targeting this parasite. In addition to its direct anti-Giardia effect, L. johnsonii CNCM I-4884 may also act as an adjuvant therapy, supporting intestinal homeostasis, enhancing host defense mechanisms, and promoting recovery of gut balance during or after antiparasitic treatments. This dual role suggests that the strain could be considered not only as a complementary therapy but, in specific cases, as a potential stand-alone probiotic treatment for canine giardiasis.