Serum metabolomics of diabetic dogs treated with daily administration of a commercially available lyophilized feces preparation.

Enteric microbial dysbiosis can contribute to the pathobiology of canine diabetes mellitus (DM) by interfering with host metabolism, promoting inflammation, and altering incretin hormone responses. Enriching and diversifying an unbalanced gastrointestinal microbiome with microbiome-based interventions such as lyophilized fecal preparations (LFP) can help improve gut function and glycemic control of diabetic dogs. This study aimed to determine the differences in the serum metabolomes, levels of interstitial glucose (IG), and 24-hour water intake of diabetic dogs treated with daily administration of LFP or placebo. A prospective, randomized, double-masked, placebo-controlled clinical trial was conducted using six DM dogs in the LFP group and six DM dogs in the placebo group. Dogs had physical examinations and 24-hour water intake assessments at admission, 2, 4, 6, and 8 weeks, with continuous IG monitoring performed throughout the study. Serum samples were collected longitudinally at baseline and during follow-up for untargeted metabolomic analysis. The marginal mean of IG after 8 weeks was lower in the LFP group (286 ± 22 mg/dL vs. 309 ± 22 mg/dL; p = 0.468), with the LFP group showing lower marginal mean IG at each time point except week five. Marginal mean log 24-hour water intake was significantly lower in the LFP group compared to placebo (mean difference − 0.24 ± 0.10, p = 0.024). Treatment groups significantly differed in metabolites with important roles in carbohydrate, protein, and lipid metabolism. Overall, our results show that LFP induced measurable metabolic alterations, with patterns generally consistent with a more favorable metabolic profile, but only minimal improvement in glycemic control.