Meeting Abstract
91.8 Wednesday, Jan. 7 A reassessment of proximate factors that trigger hypothermia in Japanese quail BEN-HAMO, Miri*; BAUCHINGER, Ulf; PINSHOW, Berry; Ben-Gurion University of the Negev; Ben-Gurion University of the Negev; Ben-Gurion University of the Negev miriammi@bgu.ac.il
Food deprived Japanese quail (Coturnix coturnix japonica) were reported to enter hypothermia with no change in its depth, in terms of reduced body temperature (Tb) and metabolic rate at different ambient temperatures (Ta). Decreased Tb was most often associated with increased thermoregulatory demands and/or reduced energy availability. Since the proximate factors that regulate the use of hypothermia are not entirely clear, we hypothesized that, as in mammals and other birds, food availability and Ta together serve to trigger the use of hypothermia in quail, and we tested the prediction that birds kept at lower Ta and deprived of food will enter deeper hypothermia than quail at a thermoneutral Ta. Twenty Japanese quail were divided into two groups, one was maintained at a thermoneutral Ta (32.6±0.2 °C) for quail, and the other below their lower critical temperature (Tlc) at 12.6±2.9 °C. Hypothermia was induced by food deprivation, and changes in body mass (mb) and Tb were compared between the groups for 11 days. Mean scotophase Tb of quail kept at thermoneutrality was significantly higher than of those kept at low Ta (40.8±0.6 °C vs. 40.1±0.5 °C, repeated measures ANCOVA F(1,7)=7.3, p<0.05). Furthermore, both groups entered hypothermia upon food deprivation, but Tb decreased more (4.3±0.4 °C vs. 2.7±0.7 °C, repeated measures ANOVA F(1,8)=23.6, p<0.01) and mb loss was greater (12.1±3.6 % vs. 7.6±1.4 %, ANOVA F(1,16)=12.4, p<0.01) in quail kept below their Tlc. The results support our hypothesis and are not consistent with previous the studies reporting no differences in hypothermic responses of quail at different Ta‘s.
