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Blood Oxygen Transport Properties during Migration to Higher Altitude of Wild Quail, Coturnix coturnix coturnix

1996; University of Chicago Press; Volume: 69; Issue: 4 Linguagem: Inglês

10.1086/physzool.69.4.30164235

1937-4267

María-Teresa Prats, Luís Palacios, S. Gallego, Miquel Riera-Codina,

Malaria Research and Control

During the breeding season, wild quail (Coturnix coturnix coturnix) rise from an altitude of 200 m to 1,200 m to feed, covering a distance of approximately 225 km in 2 mo. Blood O₂ transport properties were studied in adult male specimens captured at 200 m, 800 m, and 1,200 m. Both hematocrit (Hct) and blood hemoglobin concentration ([Hb]) increased with the increase in altitude. A positive correlation of the mean corpuscular volume (MCV) versus mean corpuscular hemoglobin (MCH) (P < 0. 001) was observed, but red blood cell (RBC) number, percentage of reticulocytes, and total plasma proteins did not show significant differences among the groups. This suggests that, during the migration, larger RBCs appeared in the circulation, which increased blood O₂ capacity. Wild quail exhibited higher blood O₂ affinity (measured at 41° C, PCO₂ of 40 Torr, or 5.3 kPa, pH 7.5) and a lower Bohr coefficient (measured between pH 7.4 and 7.8) than domestic Japanese quail (Coturnix coturnix japonica), but during the migration of the wild quail, a significant decrease in blood O₂ affinity (P50 from 27.4 Torr, or 3.6 kPa, in the 200-m group to 31.4 Torr, or 4.2 kPa, in the 1,200-m group) and in the Hill coefficient (calculated between 30% and 70% So2, 3.4 in the 200m and 800-m groups vs. 3.1 in the 1,200-m group) was observed. These changes cannot be attributed either to changes in the main erythrocyte organic phosphates or to changes in the main hemoglobin components. The changes observed during the wild quail migration could lead to an enhancement of tissue oxygenation by improving both O₂ carrying capacity and O₂ unloading to tissues.