To meet consumer requirements and expectations, innovative approaches to combining whey with other ingredients are being explored. The demand for health-promoting drinks containing vitamins, probiotics, prebiotics, minerals, and bioactive components (antioxidants) has risen, propelling market expansion. The purpose of this study was to develop a synbiotic functional whey beverage supplemented with Bifidobacterium animalis, D-allulose, and β-glucan and evaluate its microbiological, physicochemical, and influence on several health indicators in a Wistar rat model. The beverage supplemented with D-allulose had the highest average viable counts of B. animalis (9.20 log 10 CFU/g) and was the second most preferred in terms of of taste, texture and general acceptability compared to β-glucan-containing beverage. The highest TAS and lowest TOS values were determined in the serum samples of rats belonging to group WA, WG and WAG, respectively. This study might lead to additional studies focusing on specific variables and the relevance of utilizing D-allulose in dairy product processing.