Thermoregulatory and metabolic responses of Japanese quail to hypoxia.

TLDR: Japanese quail respond to hypoxia in much the same way as mammals, by reducing both Tb and VO2, by increasing thermolysis to reduce Tb.

Abstract: Common responses to hypoxia include decreased body temperature ( T b ) and decreased energy metabolism. In this study, the effects of hypoxia and hypercapnia on T b and metabolic oxygen consumption (V.O 2 ) were investigated in Japanese quail ( Coturnix japonica ). When exposed to hypoxia (15, 13, 11 and 9% O 2 ), T b decreased only at 11% and 9% O 2 compared to normoxia; quail were better able to maintain T b during acute hypoxia after a one-week acclimation to 10% O 2 . V.O 2 also decreased during hypoxia, but at 9% O 2 this was partially offset by increased anaerobic metabolism. T b and V.O 2 responses to 9% O 2 were exaggerated at lower ambient temperature ( T a ), reflecting a decreased lower critical temperature during hypoxia. Conversely, hypoxia had little effect on T b or V.O 2 at higher T a (36 °C). We conclude that Japanese quail respond to hypoxia in much the same way as mammals, by reducing both T b and V.O 2 . No relationship was found between the magnitudes of decreases in T b and V.O 2 during 9% O 2 , however. Since metabolism is the source of heat generation, this suggests that Japanese quail increase thermolysis to reduce T b . During hypercapnia (3, 6 and 9% CO 2 ), T b was reduced only at 9% CO 2 while V.O 2 was unchanged.