Tolerance of Japanese quail embryos and young chicks to hypothermia.
The purpose of this study was to explore the tolerance of Japanese quail (Coturnix coturnix japonica) embryos and young quail chicks to a very low ambient temperature. Fifty (n = 50) quail embryos at age embryonic age d 6 were placed in a cold room at 13 degrees C for 24 h. The heart rate (HR) was determined with an infrared HR sensor in an instrument called "Buddy." After 12 and 24 h, the average body temperature of the embryos was 13 degrees C with an average HR of 8.7 +/- 0.9 beats per minute (bpm). The average body temperature of 50 control embryos was 38 degrees C and they had an average HR of 301 +/- 15 bpm. The hypothermic quail embryos had a 24-h delay in hatching at 58% hatchability. The controls hatched on time at 81% hatchability. Twelve (n = 12) 6-d-old quail chicks were placed in a low-temperature environment (13 degrees C) for a period of 6 h. Quail from which the test group was selected were retained in a brooder to serve as the control comparison. The electrocardiogram HR for both hypothermic and control quail was recorded with a digital oscilloscope. The 12 quail in the low-temperature environment exhibited an immobile state of hypothermia. These hypothermic quail had an average HR of 7 +/- 0.6 bpm. The control quail had an average HR of 525 +/- 24 bpm. After emerging from the reduced-temperature environment, the immobile hypothermic quail were placed under an infrared light that produced a brooder-like temperature of 33 degrees C. After 40 min, all quail could walk around and some ate and drank.
Wentworth
B
B
Department of Animal Sciences, University of Wisconsin, Madison 53706, USA. bcwentwo@wisc.edu
Cigan
J
J
Schaaf
T
T
D000222:Adaptation, Physiological / Q000502:physiology*; D000818:Animals; D003370:Coturnix / Q000196:embryology* / Q000254:growth & development*; D007035:Hypothermia