Lu Q, Wen J, Zhang H
Institute of Animal Science, Chinese Academy of Agricultural Science, State Key Laboratory of Animal Nutrition, Beijing, 100094, China.
Poult Sci. 2007 Jun;86(6):1059-64. doi: 10.1093/ps/86.6.1059.
The effects of chronic heat stress on growth, proportion of carcass and fat deposition, and meat quality were investigated in 2 genetic types of chickens. One hundred and eight 5-wk-old male chickens from a commercially fast-growing strain (Arbor Acres, AA) and a locally slow-growing species (Beijing You chicken, BJY) were kept in the following conditions: constant optimal ambient temperature at 21 degrees C and ad libitum feeding (21AL), constant high ambient temperature at 34 degrees C and ad libitum feeding (34AL), and constant optimal ambient temperature 21 degrees C and pair-fed to the 34AL chickens (21PF). The results showed that feed intakes were decreased by heat exposure in both type of chickens at 8 wk of age (P<0.001). At 34 degrees C, AA broilers exhibited greatly decreased weight gain (22.38 vs. 61.45 g/d for 21AL) and lower breast proportion compared with 21AL, while the relevant indices of BJY chickens were not affected in hot condition. Abdominal fat deposition of BJY chickens was enhanced by heat exposure (P<0.05). Fat deposition of AA broilers was decreased in heat-exposed and pair-fed chickens. Abdominal and intermuscular fat deposition in 34AL birds, however, were enhanced compared with 21PF birds (P<0.01). The L* values, drip loss, initial pH, and shear force of breast meat in BJY chickens were not affected by treatments. In AA birds, chronic heat stress increased L* values and drip loss compared with 21AL, but pH and shear force were not affected by treatments. The results from this study indicated that the impact of heat stress was breed dependent and that BJY chickens showed higher resistance to high ambient temperature, which could be related to their increased feed efficiency and deposition of abdominal fat under heat exposure.
研究了慢性热应激对两种遗传类型鸡的生长、胴体比例、脂肪沉积和肉质的影响。选用108只5周龄雄性鸡，其中包括一个商业快速生长品系（艾维茵肉鸡，AA）和一个本地慢速生长品种（北京油鸡，BJY），将它们饲养在以下条件下：恒定最佳环境温度21℃且自由采食（21AL）、恒定高环境温度34℃且自由采食（34AL）、恒定最佳环境温度21℃且按34AL组鸡的采食量进行配对饲喂（21PF）。结果表明，在8周龄时，两种类型的鸡受热应激影响采食量均下降（P<0.001）。在34℃时，与21AL组相比，AA肉鸡体重增加显著下降（22.38 g/d对61.45 g/d）且胸肉比例降低，而BJY鸡的相关指标在热环境下未受影响。热应激使BJY鸡的腹部脂肪沉积增加（P<0.05）。热应激和配对饲喂的AA肉鸡脂肪沉积减少。然而，与21PF组鸡相比，34AL组鸡的腹部和肌间脂肪沉积增加（P<0.01）。BJY鸡胸肉的L值、滴水损失、初始pH值和剪切力不受处理影响。在AA肉鸡中，与21AL组相比，慢性热应激使L值和滴水损失增加，但pH值和剪切力不受处理影响。本研究结果表明，热应激的影响具有品种依赖性，BJY鸡对高环境温度表现出更高的抗性，这可能与其在热应激下提高的饲料效率和腹部脂肪沉积有关。
