Abstract
Introduction
Soft-shelled eggs are a major eggshell defect in poultry production, yet the underlying mechanisms of their formation remain unclear. The objective of this study was to characterize biological changes associated with soft-shelled egg formation in laying hens by integrating quantitative proteomics and untargeted metabolomics analyses of uterine fluid (UF), combined with morphological and physiological assessments.
Methods
Normal-shelled egg-producing hens (NE) and soft-shelled or shell-less egg-producing hens (SE) were selected from Langshan laying hens maintained under the same feeding and management conditions. Egg quality traits, serum biochemical indicators, duodenal and uterine morphology, TMT-based proteomics, and LC–MS-based untargeted metabolomics of UF were analyzed.
Results
Compared with the NE group, the SE group exhibited significantly reduced eggshell thickness and disrupted eggshell ultrastructure (
p
p
> 0.05). In contrast, the NE group showed significantly greater endometrial villus length, uterine mucosal fold height, and mucosal fold area than the SE group (
p
Conclusion
Soft-shelled egg formation in laying hens was associated with compromised uterine morphology and changes in the UF metabolic microenvironment. These findings provide insight into uterine fluid protein and metabolite profiles related to eggshell defects and identify candidate pathways for future validation.