Multistrain probiotics fail to modulate the asthmatic phenotype, respiratory microbiota, and immune responses in cats.

OBJECTIVE: To determine if multistrain probiotics administered to asthmatic cats treated with anti-inflammatory glucocorticoids would attenuate the asthmatic phenotype and beneficially alter respiratory, blood, and oropharyngeal (OP) microbial communities and immune parameters versus placebo. ANIMALS: 13 client-owned asthmatic cats. METHODS:A randomized, blinded, placebo-controlled clinical trial of asthmatic cats receiving anti-inflammatory glucocorticoids with oral multistrain probiotics or placebo assessed owner-perceived improvement and airway eosinophilia at baseline and after 2 weeks of treatment. Bronchoalveolar lavage fluid (BALF), blood, OP, and rectal microbial communities were compared using 16S rRNA amplicon sequencing. Real-time PCR for transcription factors, activation markers and cytokines, and IgA ELISAs were evaluated. Statistical analyses used 2-way repeated-measures ANOVA or permutational ANOVA (significance, P < .05). RESULTS: After treatment, there were no significant differences in owner-perceived clinical signs or mean ± SEM BALF eosinophils between groups. There was a significant decrease in rectal a-diversity but not in α- or β-diversity in BALF, blood, or OP between groups or over time. There were no significant differences in CD25, FoxP3, GATA, Helios, IL-4, IL-5, IL-10, IL-13, IL-17, IFN-γ mRNA, or serum or BALF IgA between groups or over time. [ABSTRACT FROM AUTHOR]