Fine-Tuning Low-Protein Diets through Vitamin E Supplementation to Avoid Ascites in Broiler Chickens

The present study investigates the effects of Vitamin E (VE) supplement on pulmonary hypertensive response of broilers fed a low-protein diet in a 42-day trial. A total of 180 male broiler chicks (Ross 308) were used in a completely randomized design. Treatments included a Normal Protein Diet (NPD) served as control, a Low-Protein Diet (LPD) with 30 g kg(-1) of crude protein lower than NPD, and a LPD supplemented with VE (100 mg kg(-1)). Analyzed protein content of NDP and LPD was 227 and 199 g kg(-1) in the starter stage and 198 and 169 g kg(-1) in the grower stage. Growth performance, blood and carcass variables and Lead II of the electrocardiogram (ECG) were recorded. Feed conversion ratio was not significantly changed by treatments. The relative weights of liver, heart, and the right to Total Ventricular weight ratio (RV:TV) as well as the S wave amplitude of ECG were significantly (P<0.05) increased by feeding LPD. However, VE supplementation of LPD significantly (P<0.05) restored these variables to similar ranges observed in NPD. Feeding LPD caused a significant decrease in serum Nitric Oxide (NO) and Uric Acid (UA) concentrations, whereas it caused a significant increase in malondialdehyde (MDA) and Heterophils to Lymphocytes ratio (H:L). Similarly, VE supplement restored these variables to similar levels observed in NPD. In conclusion, oxidative stress was involved in the pathogenesis of ascites in broilers fed with LPD, which could be counteracted by VE supplement.