# Evaluating the Adjuvant Therapeutic Effects of Probiotic Strains Lactococcus cremoris and Lacticaseibacillus paracasei on Canine Atopic Dermatitis and Their Impact on the Gut and Skin Microbiome

## TL;DR

This study shows that a probiotic blend can improve symptoms of skin allergies in dogs and may help balance gut and skin microbes.

## Contribution

The study introduces a novel probiotic combination targeting both clinical symptoms and microbiome dysbiosis in canine atopic dermatitis.

## Key findings

- Daily LCP treatment reduced skin inflammation, itching, and allergy markers in dogs with atopic dermatitis.
- LCP altered gut and skin microbiomes, reducing harmful bacteria and increasing short-chain fatty acid production.
- Functional analysis suggests LCP modulates immune-related pathways through the gut-skin axis.

## Abstract

Atopic dermatitis is a common and distressing skin disease in dogs, often causing itching, discomfort, and reduced quality of life. Current treatments can help but are not always sufficient, and long-term use of medications may have side effects. This study explored whether a special combination of two beneficial probiotics, used as a daily supplement, could support dogs with this condition. Eight dogs with atopic dermatitis were given the probiotic blend for 60 days. Over this period, the dogs showed visible improvements, with reduced skin inflammation, less itching, and lower blood markers of allergy. To better understand how the supplement might work, the bacteria living in the gut and on the skin were also studied. The probiotic blend helped restore a healthier balance of microbes and suggested a possible role in strengthening the immune system. These findings indicate that probiotics may serve as a safe and helpful addition to standard treatments for dogs with atopic dermatitis. This approach could open new opportunities to improve the health and well-being of companion animals through nutrition-based strategies.

This study investigated the therapeutic potential of a novel probiotic combination consisting of Lactococcus cremoris subsp. cremoris MP01 and Lacticaseibacillus paracasei subsp. paracasei MP02, collectively referred to as LCP, in the treatment of canine atopic dermatitis (CAD). In a 60-day open-label, single-arm trial involving eight dogs, notable clinical improvements were observed following daily LCP treatment, as evidenced by decreasing trends in Canine Atopic Dermatitis Extent and Severity Index and Pruritus Visual Analogue Scale scores, as well as a significant reduction in serum immunoglobulin E levels (p < 0.05). Microbiome and short-chain fatty acid (SCFA) analyses were subsequently conducted in a representative subset of six dogs to explore the effects of LCP on the fecal and skin microbial ecosystems. Concomitant alterations in gut and skin microbiome were observed, including a significant reduction in abundance of Erysipelotrichaceae (p < 0.05) and non-significant decreasing trends in Romboutsia, Escherichia/Shigella spp., and Shigella flexneri, along with a trend toward increased SCFA production. Functional prediction using PICRUSt suggested potential involvement of immune- and infection-related signaling pathways, including those associated with nucleotide-binding oligomerization domain-like receptors, retinoic acid-inducible gene I-like receptors and Shigellosis, supporting the hypothesis that LCP may exert its effects through modulation of the gut–skin axis. These findings support LCP as a safe and promising adjunct therapy for CAD, offering a novel microbiome-targeted approach targeting both clinical symptoms and underlying dysbiosis. Further investigation is warranted to optimize probiotic formulations and better understand the mechanisms underlying microbiome-mediated immune modulation in canine allergy.