Aulie A, Tøien Ø
Department of Physiology, Veterinary College of Norway, Oslo.
J Comp Physiol B. 1988;158(4):431-5. doi: 10.1007/BF00691140.
Electromyographic activity (EMG) from the musculus pectoralis (breast muscle), m. iliotibialis (thigh muscle) and m. gastrocnemius (leg muscle), cloacal temperature (Tb) and O2 consumption were measured in bantam cocks (Gallus domesticus) exposed to different ambient temperatures (Ta). The same parameters were measured in bantam hens incubating eggs artificially thermoregulated to 40 degrees and 25 degrees C (Te). EMG activity appeared in thigh and leg muscles at Ta below 32 degrees C (Tsh). This temperature probably represents the thermoneutral temperature (TNT) of the cock. EMG activity in breast muscles appeared at Ta below 20 degrees C, or 4 degrees C below the lower critical temperature (Tc). All muscles were quiet when the hen incubated 40 degrees C egg at Ta = Tsh. When Te was abruptly changed to 25 degrees C, EMG activity in the iliotibialis muscle appeared 3 min before the activity in the pectoralis muscle. Tb dropped from 41.2 degrees to 40.6 degrees C in 14 min. When Te was returned to 40 degrees C, the EMG activity in the pectoralis muscle disappeared almost at once, while the iliotibialis muscle was active until Tb returned to normal. Aerobic muscles seem to be responsible for shivering thermogenesis between Tc and Tsh, while anaerobic muscles are recruited at lower Ta or when the heat loss during incubation becomes severe.
在暴露于不同环境温度（Ta）的矮脚公鸡（家鸡）中，测量了胸肌、髂胫束肌（大腿肌肉）和腓肠肌（腿部肌肉）的肌电图活动（EMG）、泄殖腔温度（Tb）和耗氧量。在人工将温度调节到40摄氏度和25摄氏度（Te）孵蛋的矮脚母鸡中测量了相同参数。当Ta低于32摄氏度（Tsh）时，大腿和腿部肌肉出现EMG活动。这个温度可能代表公鸡的热中性温度（TNT）。胸肌中的EMG活动在Ta低于20摄氏度时出现，即比下限临界温度（Tc）低4摄氏度时出现。当母鸡在Ta = Tsh时孵40摄氏度的蛋时，所有肌肉都是安静的。当Te突然变为25摄氏度时，髂胫束肌中的EMG活动比胸肌中的活动提前3分钟出现。Tb在14分钟内从41.2摄氏度降至40.6摄氏度。当Te恢复到40摄氏度时，胸肌中的EMG活动几乎立刻消失，而髂胫束肌一直活跃到Tb恢复正常。有氧肌肉似乎负责在Tc和Tsh之间的颤抖产热作用，而无氧肌肉在较低的Ta或孵蛋期间散热变得严重时被调动起来。
