Effect of L-NAME on Pulmonary Arterial Pressure, Plasma Nitric Oxide and Pulmonary Hypertension Syndrome Morbidity in Broilers

摘要

Experiments were conducted to evaluate the effect of a synthetic inhibitor of nitric oxide (NO) synthesis (L-NAME) on pulmonary arterial pressure (PAP) and pulmonary hypertension syndrome (PHS) morbidity in broilers. In experiment 1, broilers were infused intravenously with L-NAME, and the mean pulmonary arterial pressure (mean PAP) and plasma NO were measured at 0, 1, 2, and 4h after the start of L-NAME infusion. The mean PAP increased and plasma NO was reduced at l-2h in broilers treated with L-NAME. In experiment 2, 180 Arbor Acres broilers were evenly divided into three groups: a control group (Group C), and two groups exposed to low environmental temperatures and fed a T_3 supplemented diet alone (Group A) or also including 100ppm L-NAME (Group B). The PHS morbidity of group A was higher than for group C but lower than for group B. Plasma endothelin-1 was higher in broilers in groups A and B than in group C (p<0.05). Plasma NO was not significantly lower in broilers of group B when compared with those in group A. The right/total ventricular weight ratio (RV/TV) and mean PAP were higher in groups A and B than in group C (p<0.05), and the RV/TV ratio increased one week earlier in group B than in group A. These results suggest that L-NAME increases broiler pulmonary arterial pressure by inhibiting the endogenous synthesis of NO, leading to pulmonary hypertension, right ventricular hypertrophy and the increase morbidity of PHS in broilers.