Bohler Mark W, Chowdhury Vishwajit S, Cline Mark A, Gilbert Elizabeth R
Department of Animal and Poultry Sciences, 2160 Litton-Reaves Hall, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
Laboratory of Stress Physiology and Metabolism, Faculty of Arts and Science, Kyushu University, Fukuoka 819-0395, Japan.
Biology (Basel). 2021 Oct 25;10(11):1095. doi: 10.3390/biology10111095.
Heat stress is one of the major environmental conditions causing significant losses in the poultry industry and having negative impacts on the world's food economy. Heat exposure causes several physiological impairments in birds, including oxidative stress, weight loss, immunosuppression, and dysregulated metabolism. Collectively, these lead not only to decreased production in the meat industry, but also decreases in the number of eggs laid by 20%, and overall loss due to mortality during housing and transit. Mitigation techniques have been discussed in depth, and include changes in air flow and dietary composition, improved building insulation, use of air cooling in livestock buildings (fogging systems, evaporation panels), and genetic alterations. Most commonly observed during heat exposure are reduced food intake and an increase in the stress response. However, very little has been explored regarding heat exposure, food intake and stress, and how the neural circuitry responsible for sensing temperatures mediate these responses. That thermoregulation, food intake, and the stress response are primarily mediated by the hypothalamus make it reasonable to assume that it is the central hub at which these systems interact and coordinately regulate downstream changes in metabolism. Thus, this review discusses the neural circuitry in birds associated with thermoregulation, food intake, and stress response at the level of the hypothalamus, with a focus on how these systems might interact in the presence of heat exposure.
热应激是导致家禽业重大损失并对全球粮食经济产生负面影响的主要环境因素之一。热暴露会给禽类造成多种生理损伤，包括氧化应激、体重减轻、免疫抑制和代谢失调。总体而言，这些不仅会导致肉类行业产量下降，还会使产蛋量减少20%，以及在饲养和运输过程中因死亡率造成的总体损失。人们已深入讨论了缓解技术，包括改变气流和饮食组成、改善建筑隔热、在牲畜建筑中使用空气冷却（喷雾系统、蒸发板）以及基因改造。热暴露期间最常见的是食物摄入量减少和应激反应增加。然而，关于热暴露、食物摄入和应激，以及负责感知温度的神经回路如何介导这些反应，人们探索得很少。体温调节、食物摄入和应激反应主要由下丘脑介导，因此有理由认为下丘脑是这些系统相互作用并协调调节下游代谢变化的中心枢纽。因此，本综述讨论了鸟类下丘脑水平上与体温调节、食物摄入和应激反应相关的神经回路，重点关注在热暴露情况下这些系统可能如何相互作用。
