Abstract
Effects of excess arginine (3.0%) and lysine (2.0%) diets, and supplements of urea (1.0%) and α-aminoisobutyric acid (AIB, 0.5%) to these diets on blood concentration of urea, ammonia and arginine and arginase activity in kidney and liver were studied in 6-month-old cockerels. Blood urea concentration increased in birds fed the diet supplemented with urea, arginine or lysine. The high blood urea observed by the excess amino acid feeding may reflect an increase in renal reabsorption of urea. Ammonia concentration decreased in birds fed the diet containing excess lysine alone. Blood arginine was high in birds fed the excess arginine diets. Kidney arginase was exactly high in birds fed the excess arginine diets and the value was emphasized by excess lysine supplementation. However, the low arginine basal diet did not increase the kidney arginase even though it contained an excess amount of lysine. Kidney arginase activity apparently decreased in all the birds by supplementation with AIB. The increase in blood arginine in these birds would represent increased renal reabsorption of arginine apart from the effect of AIB on arginase activity. Liver arginase was low and not affected by the supplements of arginine, urea and AIB. These findings showed that the regulation of arginine pool in chick kidney was accompanied by the renal functions on excretion of nitrogen compounds in addition to the effects of amino acids and urea on kidney arginase.
