Effects of heat stress on serum proteomics, laying performance and egg quality in aged laying hens

This study investigated the impact of heat stress on serum proteomics, laying performance, and egg quality in aged laying hens. Forty-eight 75-week-old Lohmann White hens were divided into two groups and subjected to either a comfort environment (26°C) or heat stress (35°C) for 28 days. Serum samples were collected on days 1 and 28 for proteomic analysis, while egg production and quality parameters were assessed daily throughout the experiment. Heat stress reduced egg production (11%), egg weight (16%), shell strength (30%), shell thickness (13.5%), and albumen height (12%). Proteomic analysis revealed the expression of proteins that bind to the heat shock proteins Hsp70 and Hsc70, exclusively in heat-stressed laying hens. Proteins related to coagulation rate were upregulated and when compared with field observations may indicate possible Disseminated Intravascular Coagulation (DIC). Apolipoprotein A and apovitelenin-1 were associated with decreased egg production and quality under heat stress.