Probiotics have been shown to alter oral microbial communities and enhance oral health in both humans and laboratory animals. Despite this, their potential effects on the oral microbiome of felines are not yet well defined. In the present 42-day experiment, twelve healthy cats were evenly divided into two treatments: a control (CON) and a composite probiotic group (CPG). The CPG diet was fortified with Bifidobacterium animalis subsp. lactis HN019, Lactobacillus acidophilus NCFM, and Lactobacillus casei LC-11, each supplied at roughly 1 × 10¹⁰ CFU per kg of feed. Oral swabs from the gingiva, tooth surface, and tongue were collected on days 0 and 42 for 16S rRNA sequencing. Across all oral regions, Bacteroidetes, Firmicutes, and Proteobacteria represented the most prevalent phyla. In the gingiva of CPG cats, seven bacterial genera—including Moraxella, Actinomyces, and Frederiksenia—were elevated. On tooth surfaces, Bergeyella and Streptococcus increased, while on the tongue, Bergeyella, Flavobacterium, and Luteimonas were enriched. Conversely, eight genera, such as Bacteroides, Desulfovibrio, and Filifactor, declined in the gingiva, Helcococcus, Lentimicrobium, and Campylobacter decreased on teeth, and Porphyromonas, Treponema, and Fusibacter reduced on the tongue. These data indicate that this probiotic blend reshapes feline oral microbiota by favoring commensal species while limiting potential pathogens, suggesting benefits for oral hygiene in cats.
