GAS-EXCHANGE AND BLOOD-GASES OF PUNA-TEAL (ANAS-VERSICOLOR-PUNA) EMBRYOS IN THE PERUVIAN ANDES

Oxygen consumption, air cell gases, hematology, blood gases and pH of Puna teal (Anas versicolor puna) embryos were measured at the altitude at which the eggs were laid (4150 m) in the Peruvian Andes. In contra st to the metabolic depression described by other studies on avian emb ryos incubated above 3700 M, 02 consumption of Puna teal embryos was h igher than even that of some lowland avian embryos at equivalent body masses. Air cell O2 tensions dropped from about 80 toor in eggs with s mall embryos to about 45 toor in eggs containing a 14-g embryo; simult aneously air cell CO2 tension rose from virtually negligible amounts t o around 26 torr. Arterial and venous O2 tensions (32-38 and 10-12 too r, respectively, in 12- to 14-g embryos) were lower than described pre viously in similarly-sized low-land wild avian embryos or chicken embr yos incubated in shells with restricted gas exchange. The difference b etween air cell and arterial O2 tensions dropped significantly during incubation to a minimum of 11 torr, the lowest value recorded in any a vian egg. Blood pH (mean 7.49) did not vary significantly during incub ation. Hemoglobin concentration and hematocrits rose steadily througho ut incubation to 11.5 g.100 ml-1 and 39.9%, respectively, in 14-g embr yos.