Co-Authors:
Yahav, S., Volcani Center, Institute of Animal Science, Agricultural Research Organization, P.O. Box 6, Bet Dagan 50250, Israel
Abstract:
Young turkeys exposed to low ambient temperature (Ta) showed significantly reduced body weight, which coincided with a reduction in energy intake and with changes in the circulatory system to accommodate higher oxygen demand. These changes included a significant increase in hematocrit, hemoglobin concentration, plasma triiodothyronine (T3) concentration, blood volume, and blood oxygen capacity. At the relatively high Ta, changes to accommodate heat dissipation included significant increases in plasma volume and panting rate. These compensations were sufficient to control body temperature (Tb). However, the higher energy expenditure for maintenance followed by significantly higher plasma triiodothyronine (T3) concentration, but with lower energy intake at low Ta, suggest a physical limitation in the ability to further increase energy intake as Ta declines. © 2002 Elsevier Science Ltd. All rights reserved.