Night‐restricted feeding improves colonic barrier function and reduces inflammation by optimizing gut microbial composition in growing pigs during the hot season.

Circadian rhythm disruptions and heat stress can cause gut microbiota dysbiosis and intestinal barrier damage, increasing the risk of inflammatory bowel disease. However, whether eating according to the circadian rhythm during the day when the ambient temperature is higher or eating against the circadian rhythm at night when the ambient temperature is relatively suitable, is better for the gut health of diurnal animals in summer has not been clarified. In this study, growing pigs were randomly assigned to a daytime‐restricted feeding or nighttime‐restricted feeding (NRF) group and raised for 18 days in summer with mild heat stress. Our results showed that NRF alleviated heat stress in pigs, as reflected by increased feed intake and decreased drinking. Microbiome analysis revealed that NRF increased the diversity of gut microbiota and abundance of short‐chain fatty acids (SCFAs)‐producing bacteria and decreased the abundance of gram‐negative and potentially pathogenic bacteria, thereby increasing SCFAs and reducing lipopolysaccharide production in the colon. These changes enhanced colonic barrier function and reduced colitis and systemic inflammation by upregulating tight junction proteins and mucin. Our findings indicate that although nighttime eating does not align with the biological habits of pigs, consuming food at a relatively suitable ambient temperature is more beneficial for gut health and homeostasis during hot seasons. Our research provides a reference for guiding the healthy feeding of farm animals in summer and a basis for developing a lifestyle that promotes gut health for individuals in tropical regions. [ABSTRACT FROM AUTHOR]