Quercetin‐based treatment improves eggshell quality in aged laying hens by modulating immune response, eggshell gland health and serum metabolome

This study suggests that compromised eggshell quality might be associated with impaired biomineralization function in the eggshell gland, potentially due to tissue damage. Conversely, dietary quercetin supplementation significantly increased eggshell thickness. We propose a potential mechanism involving the activation of glycine, serine and threonine metabolic pathways, which might enhance the biomineralization capacity and overall health of the eggshell gland. © 2025 Society of Chemical Industry.