Arterial blood oxygen partial pressure, hematocrit, haemoglobin, and cardiac index in broilers at 2600 m above sea level

Abstract

High incidence of cardiac failure in broilers due to hypoxic pulmonary hypertension (PH), produces huge economical losses. Adaptive responses include right ventricular hypertrophy and polycythemia. High energy level in feed could increase hypoxemia and therefore the degree of polycythemia, thus increasing PH. To establish normal values in arterial oxygen partial pressure (pO₂), pH, hematocrit (Ht), haemoglobin (Hb), and cardiac index (CI), 24 broilers (12 males and 12 females), chosen at random, from a population of 400 birds, were studied in Bogotá, Colombia, 2600 m above sea level. Mean values obtained were as follows: a) pO₂: 67.21 ± 5.21 mmHg; statistical differences between sexes and among ages were found (p<0.05); b) pH: 7.5 ± 0.05; c) Ht: 37.13 ± 3.27%. In males, Ht values were higher at 24 and 37 days. In females, there was a marked increment on day 31, but no significant differences were found (p<0.05). d) Hb: 11.51 ± 1.37. e) CI (right ventricular weight/total ventricular weight x 100): 26.6 ± 4.83. Highest values were found on day 31, being greater in the males. There were no statistical differences (p<0.05) between sexes or among ages for pH, Hb and CI. Hypoxemia is induced by environmental hypoxia and energy ingestion. Respiratory alcalosis was found, in comparison to data by other authors. The correlation found between pO₂ and CI indicates that, in susceptible chickens hypoxemia due to airways hypoxia induces PH and therefore there is an increase in CI.