Pasteurized Akkermansia muciniphila MucT reduces high-caloric diet-induced weight gain and alters bile acid and inflammatory profiles in dogs.

Obesity and excess body weight in companion animals represent significant and growing health concerns. Accumulating evidence indicates that obesity-associated metabolic and inflammatory dysfunction may be mitigated through dietary modulation of host-microbiome interactions. In this controlled dietary intervention study, healthy Beagle dogs were fed a commercially available high-caloric, protein-, and lipid-enriched diet at three times their daily energy requirement for 8 weeks and orally supplemented with either pasteurized Akkermansia muciniphila MucT or a placebo. Supplementation reduced weight gain and attenuated the high-caloric diet-induced expansion of Peptacetobacter hiranonis and Collinsella spp. compared to controls. Pasteurized A. muciniphila-treated animals exhibited reduced circulating pro-inflammatory cytokines and a marked decrease in fecal calprotectin levels, indicative of reduced mucosal inflammation. Longitudinal modeling identified treatment-associated alterations in inflammatory markers, while integrative multi-omics factor analysis (MOFA) and redundancy analysis (RDA) revealed coordinated changes across inflammatory, metabolic, and bile acid profiles that distinguished placebo- and pasteurized A. muciniphila-treated animals under high-caloric feeding conditions. These changes were accompanied by normalization of circulating bile acid profiles, particularly reductions in microbiome-derived secondary bile acids and oxo-derivatives associated with metabolic dysfunction. Together, these findings provide integrative insight into the immune-metabolic effects of pasteurized A. muciniphila MucT in dogs under high-caloric feeding conditions and support its potential as a dietary intervention to mitigate obesity-associated dysfunction in companion animals. As this is an exploratory proof-of-concept study conducted in a limited number of animals under controlled feeding conditions, further validation in larger and more diverse companion animal populations is warranted.IMPORTANCEObesity in pet dogs is increasingly recognized not only as a condition of excess body fat but as a chronic inflammatory disorder with profound metabolic consequences. This study demonstrates that dietary supplementation with pasteurized Akkermansia muciniphila MucT can counteract the adverse effects of a high-caloric diet in dogs by reducing body weight gain, preventing inflammation, and restoring bile acid homeostasis. These results highlight the therapeutic potential of gut-targeted nutritional strategies for managing obesity in companion animals and introduce A. muciniphila MucT as a safe, effective postbiotic with translational relevance for pet health.