Why is Pro Plan Veterinary Supplements FortiFlora still the default probiotic recommendation in clinics? I’m not anti-probiotic, but after years of seeing it handed out like water, I’m questioning whether we’re crediting it for effects that come from other parts of the product or from context. I’d love to see hard data or first-hand experiences that go beyond “my vet says so.”
Questions I can’t get good answers to:
- Strain and outcomes: The core strain is Enterococcus faecium SF68. Exactly which clinical endpoints (beyond “firmer stools”) show meaningful effect sizes in dogs and cats, and are there independent replications not funded by the manufacturer? Any number-needed-to-treat figures?
- Head-to-heads: Are there blinded comparisons versus S. boulardii, multi-strain products (e.g., Lactobacillus/Bifidobacterium blends), or high-CFU veterinary lines? If not, why do we default to FortiFlora?
- Palatability confound: FortiFlora is loaded with palatants (animal digest, liver flavor). How much of the “improvement” comes from better food intake because it makes meals tastier, rather than microbiome changes? Has anyone run a “palatant-only” control or tried matching palatability without the microbe?
- Elimination diets and allergies: Why is a poultry/animal digest-containing powder routinely recommended during strict food trials? Who has actually seen a trial fail because FortiFlora reintroduced an allergen?
- Antibiotic resistance: Enterococcus species notoriously carry resistance determinants. The company says SF68 lacks key virulence/resistance genes, but has any independent lab confirmed whole-genome data and monitored post-market isolates for gene acquisition or horizontal transfer in the gut?
- CFU reality check: Is the labeled CFU guaranteed at end of shelf life under typical shipping/storage conditions (summer heat, porch delivery)? Any third-party assays showing viable counts in real-world storage or after mixing with warm food?
- Duration and dependency: Any evidence supporting long-term daily use versus short, situational courses? Do effects persist after stopping, or do stools regress immediately (suggesting it’s acting more like a crutch)?
- Synbiotic Action vs original: The SA version adds prebiotics. Is there proof SA outperforms the original in chronic enteropathies, antibiotic-associated diarrhea, or soft-stool “stress” cases? Or is this just line extension marketing?
- With antibiotics: If pets are on metronidazole, tylosin, clavamox, etc., are we just killing SF68 on contact? Any data on timing/dosing that preserves viability or shows clinical benefit despite concurrent antibiotics?
- Immunocompromised animals: Documented cases of probiotic-associated bacteremia/sepsis in dogs/cats? How are clinicians risk-stratifying before recommending an Enterococcus-based product?
- Cost-benefit: For chronic GI cases, has anyone seen superior outcomes (or equal outcomes at lower cost) with non-Enterococcus options like S. boulardii CNCM I-745, spore-based Bacillus, or high-CFU multi-strain products? What about simply adding a proven prebiotic fiber (psyllium, inulin/FOS) and improving diet digestibility?
- Label transparency: Exact source species for “animal digest” and “liver flavor”? Cross-contamination controls? This matters for true elimination diets and poultry-allergic pets.
What would actually change my mind:
- Blinded, independent, head-to-head clinical trials with clear endpoints and effect sizes
- Third-party CFU viability tests at end-of-shelf-life after heat exposure
- Independent WGS data with ongoing surveillance showing no resistance/virulence acquisition
- A palatant-controlled study showing benefit beyond flavor-driven intake
If you’ve got links to independent studies, COAs, lab tests, or detailed case series (good or bad), please drop them. I’m not looking for brand loyalty or “works for me” alone-show me data or a rigorous n=1 with controls.