Effects of Heat Stress on Breast Muscle Metabolomics and Lipid Metabolism Related Genes in Growing Broilers.

With global warming and worsening climatic conditions, heat stress (HS) has become a significant challenge affecting the development of poultry production. In this study, we aimed to determine the effects of HS on breast muscle metabolomics and lipid metabolism-related genes in growing broilers. One hundred twenty 29-day-old Arbor Acres broilers were randomly divided into normal temperature (NT; 21 ± 1 °C) and heat stress (HS; 31 ± 1 °C) groups, with six replicates (ten birds in each replicate) in each group, raised for 14 days in two environment chambers at 60 ± 7% relative humidity. Compared with the broilers in the NT group, the average daily food intake, average daily gain and breast muscle yield in the HS group were significantly lower ( < 0.05). The feed conversion ratio was significantly higher in the HS group ( < 0.05). The concentrations of serum corticosterone, free fatty acids and cholesterol and the percentage of abdominal fat of broilers in the HS group were significantly higher ( < 0.05) than the values of the broilers in the NT group. Untargeted breast muscle metabolome analysis revealed 14 upregulated differential metabolites, including glycerophosphocholine, and 27 downregulated differential metabolites, including taurine, in the HS group compared to the NT group; the HS group also displayed significant effects on six metabolic pathways compared to the NT group ( < 0.05). The mRNA expression levels of peroxisome proliferator-activated receptor gamma coactivator-1-alpha, peroxisome proliferator-activated receptor alpha () and ATP-binding cassette transporter A1 in the liver and breast muscles were significantly decreased in the HS group compared with the NT group ( < 0.05). The collective findings reveal that HS can cause disorders in breast muscle lipid metabolism in broilers. The gene might be the key gene in the mechanism of the lipid metabolism that is induced by HS in breast muscle of broilers. These findings provide novel insights into the effects of HS on chicken growth.