Effect of the Probiotic Bacillus subtilis DE-CA9(TM) on Fecal Scores, Serum Oxidative Stress Markers and Fecal and Serum Metabolome in Healthy Dogs

SIMPLE SUMMARY: This study evaluated the daily administration of 1 × 10(9) cfu Bacillus subtilis probiotics (DE-CA9(TM)) on general health, fecal scores, microbiome, as well as fecal and serum metabolome in 10 healthy adult Beagle dogs. Our data suggest that this probiotic is safe to administer to healthy Beagle dogs. Furthermore, DE-CA9(TM) administration had a potential positive effect on several markers of oxidative stress, in addition promoting an increase in serum tryptophan levels in supplemented dogs. ABSTRACT: Background: There is increasing interest in the use of Bacillus species as probiotics since their spore-forming ability favors their survival in the acidic gastric environment over other probiotic species. The subsequent germination of B. subtilis to their vegetative form allows for their growth in the small intestine and may increase their beneficial effect on the host. B. subtilis strains have also previously been shown to have beneficial effects in humans and production animals, however, no reports are available so far on their use in companion animals. Study design: The goal of this study was therefore to investigate the daily administration of 1 × 10(9) cfu DE-CA9(TM) orally per day versus placebo on health parameters, fecal scores, fecal microbiome, fecal metabolomics, as well as serum metabolomics and oxidative stress markers in ten healthy Beagle dogs in a parallel, randomized, prospective, placebo-controlled design over a period of 45 days. Results: DE-CA9(TM) decreased the oxidative status compared to controls for advanced oxidation protein products (AOPP), thiobarbituric acid reactive substances (TBARS) and reactive oxygen metabolites (d-ROMS), suggesting an antioxidant effect of the treatment. Fecal metabolomics revealed a significant reduction in metabolites associated with tryptophan metabolism in the DE-CA9(TM)-treated group. DE-CA9(TM) also significantly decreased phenylalanine and homocysteine and increased homoserine and threonine levels. Amino acid metabolism was also affected in the serum metabolome, with increased levels of urea and cadaverine, and reductions in N-acetylornithine in DE-CA9(TM) compared to controls. Similarly, changes in essential amino acids were observed, with a significant increase in tryptophan and lysine levels and a decrease in homocysteine. An increase in serum guanine and deoxyuridine was also detected, with a decrease in beta-alanine in the animals that ingested DE-CA9(TM). Conclusions: Data generated throughout this study suggest that the daily administration of 1 × 10(9) cfu of DE-CA9(TM) in healthy Beagle dogs is safe and does not affect markers of general health and fecal scores. Furthermore, DE-CA9(TM) administration had a potential positive effect on some serum markers of oxidative stress, and protein and lipid metabolism in serum and feces.