Increased dietary protein elevates plasma uric acid and is associated with decreased oxidative stress in...

Uric acid is an important antioxidant and methods to elevate its plasma concentration may be important in animal health. In a first study, the effect of dietary protein on plasma uric acid (PUA) and glucose concentrations were determined in 3-week-old chicks. Twenty-four broiler chicks were randomly assigned to four diets: a commercial control diet (C, 20% crude protein), low protein (LP) containing 10% casein, medium protein (MP) containing 20% casein or high protein (HP) containing 45% casein for a 3-week experiment. PUA concentration increased (P<0.05) in chicks fed HP diet and declined (P<0.05) in chicks fed LP while plasma glucose concentrations were lower (P<0.05) in chicks fed the LP diet at the end of the study. In a second study, PUA and leukocyte oxidative activity (LOA) were determined in broilers fed C, LP, MP or HP diets for 4 weeks. As in the first study, dietary protein directly affected PUA concentrations. In birds consuming HP diets, PUA was negatively correlated (P=0.06) with lowered LOA. These data support the view that increases in dietary protein can increase PUA concentrations, which can ameliorate oxidative stress.