TABLE 7.

Overview of heat stress effects on the GI microbiota of chickens.

Class	Heat stress effect	Pros	Cons	References a
GI microbiota	Perturbation of the GI ecosystem and microbial community stability → dysbiosis	—	Positive feedback loop among dysbiosis, GI barrier dysfunction, and GI inflammation → ↓ health and performance	Suzuki et al. (1983) , Suzuki et al. (1989) , Lan et al. (2004) , Burkholder et al. (2008) , Soliman et al. (2009) , Song et al. (2014) , Chen et al. (2018), Tsiouris et al. (2018) , Wang X. J. et al. (2018) , Wang et al. (2020) , Ducatelle et al. (2018) , Shi et al. (2019) , Xing et al. (2019) , Zhu et al. (2019) , He et al. (2019a), He et al. (2019b) , He et al. (2021), Le Sciellour et al. (2019), Xiong et al. (2020) , Liu et al. (2020) , Liu et al. (2022)
			↑ susceptibility to GI pathogen colonization → ↑ GI disorders (e.g., necrotic enteritis) → ↓ health and performance

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.