TABLE 5.

Overview of heat stress effects on the cardiovascular system of chickens.

Class	Heat stress effect	Pros	Cons	References a
Cardiovascular system	Peripheral vasodilatation and GIT vasoconstriction	↑ sensible heat dissipation	GIT hypoperfusion →	Hales (1973), Hall et al. (1999), Koutsos and Arias (2006) , Rao (2008), Lambert (2009), Baumgard and Rhoads (2013), Bischoff et al. (2014), Rostagno (2020)
			↓ nutrient supply to the GIT → ↓ GI barrier and functionality
			GIT hypoxia → oxidative stress → ↓ GI barrier and functionality

Upward arrow (↑), increase; downward arrow (↓), decrease; rightward arrow (→), consequence/degeneration.

^aInclude studies on non-avian species that have exhibited comparable heat stress effects and responses to those observed in chickens. Studies with the focus on chickens or poultry are highlighted in bold.