HEMATOPOIETIC AND RIGHT-VENTRICULAR RESPONSE TO INTERMITTENT HYPOBARIC HYPOXIA IN MEAT-TYPE CHICKENS

The purpose of this study was to examine the effect of simulated high altitude (2054 m) on erythropoiesis and pulmonary hypertension-induced right ventricular hypertrophy. Broiler chickens were reared at atmosp heric pressure (altitude 295 m) or in a hypobaric chamber at an atmosp heric pressure of 592 mmHg (calculated partial pressure of oxygen: 124 mmHg; calculated altitude and O-2 equivalents: 2054 m and 16.3%) for 2-, 4-, 8- or 16-h periods out of each 24 h. Hypoxia of 2 and 4 h per day had little effect on blood parameters although there was some indi cation of right ventricular hypertrophy. Hypoxia of 8 or 16 h produced significantly higher haematocrit and haemoglobin levels than controls , and there was moderate to marked right ventricular hypertrophy. The relationship between right ventricular hypertrophy and duration of hyp oxia was greater than between polycythaemia and duration of hypoxia.