The Effects of Dietary Enterococcus faecalis HHP003 Supplementation on Gut Microbiota Composition and Gut Health in Cats with Mild Diarrhea

As a probiotic lactic acid bacterium, E. faecalis regulates intestinal flora, strengthens the intestinal barrier, and enhances immunity in the host. However, as a new strain isolated from healthy feline gut, E. faecalis HHP003 has an unclear effect on feline intestinal health. Twenty cats with mild diarrhea were randomly assigned to two groups: one group received the standard diet (MD), while the other group received supplemental E. faecalis HHP003 (EF). Meanwhile, 10 healthy cats were enrolled as a healthy control group (CON). After 42 days of intervention, the EF group exhibited significantly reduced serum inflammatory markers (TNF-α and IL-1β), as well as decreased levels of calprotectin and lipopolysaccharide, compared with the MD group (p < 0.05). The intestinal microbial diversity was altered in the EF group, with increased Chao and Shannon indices (p < 0.05). Specifically, the relative abundances of Bacillota, Bacteroidota, and Ruminococcaceae were significantly higher in the EF group than those in the MD group (p < 0.05). Metabolomic analysis identified 697 differential metabolites and nine KEGG metabolic pathways (p < 0.05) between the EF and MD groups. Furthermore, the study identified significant associations between the gut microbiota and selected serum metabolites. In summary, E. faecalis HHP003 supplementation was associated with reduced serum inflammatory responses, improved intestinal inflammation and barrier markers, and altered gut microbiota and serum metabolite levels in cats with mild diarrhea.