Official Journal of the College of Veterinary Medicine, University of Al-Qadisiyah

Age -Dependent Regulation of MUC1 and MUC4 Gene Expression and Histochemical Mucin Distribution in the Trachea of Broiler Chickens (Gallus gallus)

Document Type : Research Paper

Authors

1 Department of Anatomy and Histology, College of Veterinary Medicine, University of Al-Qadisiyah,Iraq

2 Department of Anatomy and Histology, College of Veterinary Medicine, University of Al-Qadisiyah, Iraq

Abstract
Background: This study demonstrates that the trachea of broiler chickens undergoes significant age-dependent mucosal remodeling, characterized by differential expression of mucin genes and variations in mucin composition. Notably, MUC1 gene expression exhibited a dynamic pattern, with a significant upregulation observed at 21 days of age compared to 7 days, indicating that this stage represents a critical period for enhanced epithelial protection. This peak likely corresponds to the rapid growth phase in broilers, during which the respiratory system becomes more exposed to environmental stressors and pathogens, necessitating stronger mucosal defense mechanisms. In contrast, MUC4 expression remained stable across all examined age groups, suggesting a constitutive role in maintaining epithelial integrity rather than responding to developmental or environmental changes.
Histochemical findings further supported these molecular results, revealing a predominance of PAS-positive neutral mucins over acidic mucins in the tracheal epithelium. This suggests that neutral mucins play a more prominent role in the protective barrier function of the trachea during broiler development. The combined molecular and histochemical evidence highlights the coordinated regulation of mucosal defense components in the respiratory system.
Overall, these findings provide important baseline data for understanding the development of mucosal immunity in broiler chickens. They also offer valuable insights into how the respiratory system adapts to growth and environmental challenges, which could have implications for improving poultry health management and disease resistance strategies.

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