Effects of Early Feed Restriction on Lipid Peroxidation, Pulmonary VascularRemodeling and Ascites Morbidity in Broiler Under Normal and Cold Temperature

摘要

Two experiments were conducted to evaluate the effects of early feed restriction on the lipid peroxidation, pulmonary vascular remodeling and ascites syndrome in broiler under normal or low ambient temperature. In experiment 1, the restricted chicks were fed 8 hours per day either from 7 to 14 d or from 7 to 21 d, while the controlled chicks were fed ad libitum. In experiment 2, the restricted chicks were fed 80% or 60% of previous 24 hours feed consumption of full-fed controls for 7 days from 7 to 14 d. On d 14, half of the chicks in each treatment both in experiment 1 and experiment 2 were exposed to low ambient temperature to induce ascites syndrome. Body weights were recorded weekly. The incidences of ascites and other disease were recorded to determine ascites morbidity and total mortality. Blood samples were taken on d 14, 21, 28, 35 and 42 to measure the plasma malonilaldehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels. On d 42, Samples were taken to determine the right / total ventricular weight ratio (RV/TV), vessel wall area /vessel total area ratio (WA/TA) and mean media thickness in pulmonary arterioles (mMTPA). The results showed that low temperature significantly increased the plasma MDA concentration and decreased the plasma SOD and GSH-Px activity. The RV/TV, WA/TA and mMTPA on d 42 were significantly increased in birds exposed to cold, so as the ascites morbidity. Early feed restriction markedly decreased the plasma MDA concentration. The plasma SOD and GSH-Px activity of feed restricted chicks were markedly higher than that of the fed ad libitum. All early feed restriction treating reduced ascites morbidity and total mortality. On d 42, the RV/TV, WA/TA and mMTPA of feed restricted broilers were lower than that of the uncontrolled broilers. The results suggested that early feed restriction alleviated the lipid peroxidation, enhanced the activity of enzymatic antioxidant and finally inhibited pulmonary vascular remodeling. These changes might be associated with reduced ascites incidence.