EFFECT OF HYPOBARIC HYPOXIA ON SLOW-GROWING AND FAST-GROWING CHICKENSFED DIETS WITH HIGH AND LOW-PROTEIN LEVELS

The occurrence of pulmonary hypertension syndrome in fast-growing broi ler chickens and slow-growing leghorns was studied. In two similar tri als, broiler chickens and white leghorns were placed either at low alt itude (295 m) or in hypobaric chambers (simulated high altitude of 205 4 m) and fed either a high- (22%) or low-protein (17%) ration. Right v entricular hypertrophy as measured by right-ventricle: total-ventricle (RV:TV) weight ratio was used as an indicator of pulmonary hypertensi on. The leghorns did not develop pulmonary hypertension as the result of polycythemia induced by simulated high altitude. Compared with low- altitude broilers and leghorns, broilers reared at high altitude respo nded with significantly higher hematological values and 56% ascites mo rtality because of right ventricular failure from pulmonary hypertensi on, as measured by an increased RV:TV ratio.