Bifidobacterium animalis Subspecies lactis CECT 8145 Affects Markers of Metabolic Health in Dogs During Weight Gain and Weight Loss

This study explored the effects of <i>Bifidobacterium animalis</i> subspecies <i>lactis</i> CECT 8145 (<i>B. animalis</i> CECT 8145)-in both live probiotic and heat-treated postbiotic form-on metabolic health and digestion in male and female Labrador Retrievers during weight gain and loss. The study consisted of two, seven-week phases: weight gain (200% maintenance energy intake; Phase (1) and weight loss (100% maintenance energy requirement for ideal weight; Phase (2), separated by a 2-week washout period. In each phase, forty-five adult Labrador Retrievers (1.6-12.5 years) were randomly assigned to daily supplementation with live <i>B. animalis</i> CECT 8145 probiotic (PRO, <i>n</i> = 15), heat-treated <i>B. animalis</i> CECT 8145 postbiotic (POST, <i>n</i> = 15), or placebo control (CON, <i>n</i> = 15). Body weight, body condition score, fecal quality and food consumption were monitored throughout the study, and body composition, fecal, and blood samples were analyzed at the beginning and end of each phase. Digestibility was evaluated at the end of each phase. Post-prandial glucose responses were affected by intervention during weight loss, with a 6% reduction in the area under the curve (AUC) in POST compared to CON dogs (<i>p</i> = 0.035). Glucagon was decreased in females supplemented with POST (<i>p</i> = 0.0014), while POST males showed increased glucagon-like peptide-1 (GLP-1) compared to CON (<i>p</i> = 0.016) during weight gain. Serum GGT levels decreased, within the normal reference range, in POST compared to CON dogs during weight gain (post hoc <i>p</i> = 0.041). Fecal isovalerate was also reduced and fat digestibility increased (<i>p</i> = 0.026) in POST compared to CON (<i>p</i> = 0.018) during weight gain. There was a significant association between the group and gastric inhibitory polypeptide (GIP), with a decrease in GIP in POST over time (<i>p</i> = 0.030), and glucagon tended to be decreased in POST compared to CON (<i>p</i> = 0.073). Overall, these findings suggest supplementation with postbiotic <i>B. animalis</i> CECT 8145 may improve certain markers of Labrador retrievers' metabolic health.