The Effects of Graded Arginine Levels on Nitrogen Metabolism in the Lean Adult Dog

The objective of this study was to determine if feeding increased dietary arginine affects indices of inflammation and whole body N metabolism. Three diets were used in this study: a control (0.92% arginine), control plus 0.5% supplemental arginine, and control plus 1.0% supplemental arginine. The diets were fed to 9 adult, spayed Beagles in a replicated 3x3 Latin Square experiment. Experimental periods were 28 days long with blood collection on days 14 and 28, and total urine and fecal collections for the final 6 days of each period. Nitrogen intake was increased (P < 0.0001) by increasing dietary arginine. Dry matter digestibility was 1.4% lower (P = 0.0124) for the +1.0% Arginine diet. Nitrogen digestibility was greatest (P = 0.0014) for the +0.5% diet. Nitrogen absorbed was greater (P < 0.0001) for both supplemented diets than control, however, N retained and urea excretion did not differ across treatments. A number of inflammatory biomarkers and hormones were evaluated in urine and serum samples. No differences were detected in any of these biomarkers. Despite some subtle changes in N metabolism, it does not appear that addition of dietary arginine to these diets is beneficial for the adult dog at maintenance.