Oral Administration of Freeze‐Dried <scp> <i>Lactobacillus zeae</i> </scp> Alleviates Periodontitis by Affecting the Oral and Intestinal Flora

ABSTRACT Due to the high incidence of periodontal diseases in pet cats and dogs, the purpose of this study is to screen bacteria with beneficial oral health effects and assess the effectiveness of its freeze‐dried cell. In this study, we explored the effects of oral probiotics by determining the bacteriostatic ability, percentages of self‐aggregation and co‐aggregation in vitro, and through microbial community analysis, the alleviating effect of freeze‐dried cells on periodontitis and its mechanism of action were evaluated. Lactobacillus zeae N165 significantly inhibited Fusobacterium nucleatum and Porphyromonas gingivalis , and it had high co‐aggregation rates of 96.78% and 88.94% with F. nucleatum and P. gingivalis , respectively. In vivo, freeze‐dried L. zeae N165 cells significantly reduced alveolar bone resorption, TNF ‐α, and IL ‐6 levels in rats with periodontitis, maintained a healthy oral and intestinal microbial community structure, and regulated the dominant species to alleviate periodontitis. The prediction of functions by the KEGG database analysis of oral flora revealed that freeze‐dried L. zeae N165 cells may alleviate periodontitis via four pathways: reduction of glutamine degradation, modulation of lipopolysaccharide levels, biosynthesis of polyketide glycan units, and biotin metabolism. L. zeae N165 showed promising results in both in vitro and in vivo experiments, suggesting new directions for the oral probiotics industry.