Haematopoietic 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 atmospheric pressure (altitude 295 m) or in a hypobaric chamber at an atmospheric pressure of 592 mmHg (calculated partial pressure of oxygen: 124 mmHg; calculated altitude and O2 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 indication 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 hypoxia was greater than between polycythaemia and duration of hypoxia.