Background: Skin and coat health is a primary concern for pet owners, yet evidence-based nutritional interventions remain limited. Indoles are beneficial microbial metabolites that activate the aryl hydrocarbon receptor, a regulator of skin immune and inflammatory responses, offering a promising approach to influence the gut–skin axis.
Hypothesis/
Objectives: This study evaluated whether daily supplementation with Superculture® Pet Immune (SPI), an indole-rich postbiotic, improved coat quality in healthy dogs compared to placebo.
Animals: Forty healthy dogs (body condition score 4-5) were enrolled from a research colony of beagles and small breed dogs.
Methods: In this double-blind trial, dogs were stratified into two groups of 20 based on weight, body condition score, and sex. After a 7-day washout, groups received either SPI or placebo as a powder topper for 90 days. Coat softness and glossiness were assessed using a validated 4-point scale at Days 0, 28, 56, and 91.
Results: SPI improved coat softness at Day 56 (p = 0.001) and Day 91 (p = 0.001), while placebo only trended toward improvement (p = 0.09 & p = 0.07, respectively). SPI improved coat glossiness at Day 56 (p = 0.01) and Day 91 (p = 0.001), while placebo did not improve at Day 56 (p = 0.16) and only trended toward improvement at Day 91 (p = 0.09).
Conclusions and Clinical Importance: Indole-rich postbiotic supplementation significantly improved coat softness and glossiness, corroborating previous findings. SPI offers veterinarians and pet parents a safe, evidence-based nutritional approach for supporting skin and coat health in dogs.
Learning Objectives:
Describe the role of indole metabolites and aryl hydrocarbon receptor activation in modulating skin and coat health through the gut–skin axis in dogs.
Evaluate the clinical evidence supporting indole-rich postbiotic supplementation as a nutritional intervention for improving coat softness and glossiness in healthy dogs.
