Effect of age on eggshell color and Haugh unit of eggs, protoporphyrin IX and ovomucin deposition and related gene expression in Hyline Brown laying hens

Key Points

• The aim is to investigate how age affects eggshell color and quality as well as the deposition of certain proteins and gene expression in laying hens.
• Analyzed eggshell color and Haugh units of eggs over different ages of Hyline Brown laying hens.
• Measured deposition levels of protoporphyrin IX and ovomucin in eggshells.
• Examined gene expression related to egg quality and protein secretion.
• Older hens produced eggs with poorer eggshell color and lower Haugh units.
• Decreased gene expression correlated with aging, leading to reduced secretion of protoporphyrin IX and ovomucin.
• Increased lipid peroxidation was noted in the eggshell gland and magnum as hens aged.