Supplemental L-arginine Modulates Developmental Pulmonary Hypertension in Broiler Chickens Fed Reduced-Protein Diets and Reared at High Altitude

Abstract

This experiment was conducted to evaluate the effects of supplemental L-arginine (ARG) in reduced-protein diets on cardiopulmonary performance and intestinal morphology in the broilers reared at high altitude. A total of 156 day-old male broilers were randomly assigned to 3 treatments and 4 replicates of 13 chicks and reared up to 42 days of age. Treatment groups were designed as a normal-protein diet (NPD), a reduced-protein diet (RPD) with 30 g/Kg less crude protein compared to the NPD, and a reduced-protein diet plus 4 g/Kg L-arginine (RPD + ARG). There were no significant differences among dietary treatments for intestinal morphology and weight gain. Feed conversion ratio was improved in the chickens fed RPD + ARG compared to those fed RPD alone. The right to total ventricular weight ratio (RV:TV) was significantly increased in the chickens fed RPD when compared to those fed NPD or RPD + ARG. Serum nitric oxide and amplitude of the S waves of electrocardiogram significantly declined by reducing dietary protein content. Relative expression of endothelin-1 (ET-1) gene was higher in the heart and lungs of chicks fed RPD than those fed NPD and it was off set when ARG supplemented to RPD (<em>P). In conclusion, supplementing reduced-protein diets with ARG would be an effective strategy to prevent the development of pulmonary hypertension by increase in nitric oxide, and decrease in RV:TV and ET-1 gene expression.</em>