Preventive effects of a standardized hydro-ethanolic extract of blackcurrant (Ribes nigrum L.) on high-fat diet-induced overweight in Beagle dogs

Blackcurrant (BC) extract has been reported to exert anti-obesity effects. However, its impact on high-fat diet (HFD)-induced obesity-related disorders remains insufficiently documented. Moreover, it is not yet known whether BC extract with a composition similar to that of the whole plant ( totum ) differentially affects obesity when compared to its isolated active compounds [ 1 ]. This study evaluates the effects of a standardized hydro-ethanolic extract of blackcurrant leaves (BC-HLE) in a HFD-induced overweight dog model, comparing it to quercetin (QUE) and its combination with a Lactobacillus -based probiotic (PRO), consisting of three strains ( plantarum BL2203 ; fermentum BL3413 and rhamnosus GG BL3113 ). Twenty-four 3-year-old Beagle dogs (n=6/group) received: HFD alone (34% energy from beef fat), HFD+BC-HLE (12.3 mg/kg BW), HFD+BC-HLE+PRO, or HFD+QUE (0.3 mg/kg BW. Supplements were mixed into kibble and administered according to the dogs’ body weight for 12 weeks. By the end of the study, all dogs became overweight. The HFD group was associated with an increase in abdominal circumference, an elevated body condition score and signs of gut dysbiosis. The BC-HLE, whether used alone or in combination with the probiotic, mitigated the increase in abdominal circumference, modulated the gut microbiome, and reduced oxidative stress. Some of these effects were also observed with QUE, though to a lesser extent. The observed efficacy may be attributed to interactions between quercetin and other phytochemicals, such as proanthocyanidins, suggesting a beneficial bioactive synergy. These findings highlight the potential of BC-HLE as a preventive tool against canine obesity and its related disorders. However, the complex interactions between the extract and the probiotic require further investigation. Publication History Article published online: 05 March 2026 © 2026. Thieme. All rights reserved. Georg Thieme Verlag KG Oswald-Hesse-Straße 50, 70469 Stuttgart, Germany