Transcriptomic analysis of the liver in aged laying hens with different eggshell strength

Area of Science:

• Animal Science
• Genomics
• Molecular Biology

Background:

• Eggshell strength is crucial for egg quality, safety, and economic outcomes in poultry production.
• Factors influencing eggshell strength are known, but the liver's molecular mechanisms in aged hens remain unclear.
• Understanding these mechanisms is vital for addressing decreased eggshell quality in older laying hens.

Purpose of the Study:

• To identify hepatic molecular factors associated with variations in eggshell strength in aged laying hens.
• To elucidate the transcriptomic differences between hens producing strong and weak eggshells.
• To provide insights into the liver's role in eggshell quality decline.

Main Methods:

• Screening of 500 aged Hy-line Brown laying hens (92 weeks old) for eggshell strength variation.
• Selection of 12 hens (6 with strong eggshell strength (SES) and 6 with weak eggshell strength (WES)) for liver tissue collection.
• RNA sequencing to identify differentially expressed genes (DEGs) between SES and WES groups.

Main Results:

• Identified 2,084 differentially expressed genes (DEGs) between WES and SES groups (1,358 upregulated, 726 downregulated in WES).
• Enriched pathways include mTOR, JAK-STAT, MAPK, and insulin resistance signaling.
• Upregulation of genes related to fatty liver disease, oxidative stress, and altered bone resorption activity observed in WES group.

Conclusions:

• Hepatic transcriptomic analysis reveals key molecular pathways and genes influencing eggshell strength in aged laying hens.
• Findings suggest links between liver function, fatty liver disease, oxidative stress, bone metabolism, and eggshell quality.
• This study enhances understanding of the molecular basis for decreased eggshell strength in aged hens, paving the way for targeted interventions.