Heat Stress Responses in Birds: A Review of the Neural Components
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
Author to whom correspondence should be addressed.
Academic Editors: Jeanne M. Fair and Martha Desmond
Received: 31 August 2021
Revised: 15 October 2021
Accepted: 20 October 2021
Published: 25 October 2021
Heat stress is a major environmental condition negatively impacting the wellbeing of various avian species. In chickens, heat exposure is associated with disruption of metabolic and immune system function, and an increased risk of mortality. This has a negative impact on the food economy, as chicken products make up roughly 34% of the world’s protein. Techniques to mitigate exposure to high temperatures have been discussed in depth, and most research suggests that the root cause of heat stress-induced physiological aberrations is alterations in the stress response and reduced food intake. Unfortunately, little is known about thermoregulation in birds. That thermoregulation, food intake, and the stress response are all mediated by the hypothalamus make it tempting to speculate that it is the central hub at which these systems interact and signals from diverse pathways are integrated. 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.