Effects of Blueberry Consumption on Preference, Digestibility, and Oxidative Balance in Dogs

Abstract

The growing awareness of the diet-health connection drives interest in natural dog diets, which replace synthetic additives like antioxidants with natural ingredients. In Trial 1 of this study, preference for diets containing powdered Fucus algae (1.5%), powdered clove (0.45%), or whole blueberries (3%) was evaluated using the two-bowl method. Dogs exhibited a clear preference for the blueberry diet. In Trial 2, the impact of blueberries on apparent digestibility was assessed. Twelve Beagles were fed either a control diet (CON) or the same diet with 3% blueberries (BLU). No differences were observed, except for cellulose digestibility. Trial 3 evaluated the effect of blueberries on oxidative status during submaximal exercise. The same dogs were fed either CON or BLU diets for 4 weeks, with eight dogs completing treadmill exercises at the start and end of this period. Blood samples were collected before and after exercise. Trial 3 was replicated in summer and winter, reversing diet groups. Exercise increased creatine kinase (CK), urea, and malondialdehyde and decreased glutathione peroxidase, with stronger effects in summer, suggesting heat stress. Although the BLU diet did not mitigate exercise-induced changes, lower resting CK levels after 4 weeks in summer suggest protection against heat stress, warranting further study.

Keywords: Beagles; antioxidants; blueberries; digestibility; dogs; exercise; oxidative stress; preference.