304 Oral health indices and microbiota populations of adult cats consuming wet or dry diets.

Abstract Oral microbiota play a critical role in feline periodontal disease, with wet foods often being associated with negative impacts on oral health. However, the oral microbial communities of cats remain underexplored. This study aimed to evaluate differences in the oral health indices and microbiota of cats fed a dry or wet diet. All animal procedures were approved by the University of Illinois Institutional Animal Care and Use Committee prior to experimentation. At baseline, all 20 healthy adult cats had their teeth cleaned and polished by a veterinarian. Cats were then randomly allotted to two treatments: dry diet (Cat Chow Complete with Real Chicken Dry Cat Food, Nestle Purina, St. Louis, MO) or wet diet (Friskies Pate Country Style Dinner Canned Cat Food, Nestle Purina, St. Louis, MO). After 28 weeks of diet consumption, sulfur-containing compound concentrations were measured using a halimeter, salivary pH was measured, plaque, calculus and gingivitis scores were assessed by a blinded veterinary, and supragingival and subgingival plaque samples were collected for microbiota analysis using 16S rRNA gene amplicon sequencing. Plaque microbiota data were evaluated using QIIME2. All other data were analyzed using the Mixed Models procedure of SAS, with P< 0.05 considered statistically significant. Cats fed the dry diet had lower calculus coverage and thickness than those fed the wet diet, but other health measures were not different between treatment groups. In supragingival plaque, cats fed the wet diet had lower alpha diversity measures (i.e., Observed features, Fisher index) than those consuming the dry diet. Additionally, there was a clear separation in microbiota communities between the dry- and wet-fed cats based on both unweighted and weighted UniFrac distances. The relative abundances of several bacterial taxa, including Synergistetes, Bacteroidota, Fretibacterium, Christensenellaceae R-7 group, Tannerella, Filifactor, and Bacteroides were more abundant in cats fed the wet diet. In contrast, the relative abundances of Proteobacteria, Patescibacteria, Campylobacter, Streptococcus, Bergeyella, Flavobacterium, Capnocytophaga, Corynebacterium, JGI 0000069-P22, Gracilibacteria, Luteimonas, Lautropia, and Absconditabacteriales SR1 were more abundant in cats fed the dry diet. Although most health indices were not different between treatment groups, cats fed the dry diet had higher levels of health-associated genera (Capnocytophaga and Corynebacterium) and lower levels of disease-associated genera (Filifactor, Tannerella, and Fretibacterium). The lower calculus scores and microbial shifts suggest oral health benefits of feeding dry diets, but more research is necessary to understand feline oral microbiota populations and how they contribute to biofilm formation, calculus and plaque buildup, and oral disease in cats.