Age-Dependent Changes in Muscle Regulatory Factors and Glycogen in Broiler Chickens: A Histological and Molecular Study
Age-Dependent Changes in Muscle Regulatory Factors and Glycogen in Broiler Chickens: A Histological and Molecular Study
Nabeel Abd Murad Al-Mamoori*, Haneen Abdul Ameer Abbas**
ABSTRACT
Muscle regulatory factors (MYF5 and MYOG) and myosin heavy chain isoform (MYH7) play a crucial role in muscle development and adaptation, making them key candidate genes for muscle growth traits in chickens. This study examined glycogen content and the expression of MYF5, MYOG and MYH7 genes in the Iliotibialis muscle of broiler chickens. Fresh muscle samples were collected from the Iliotibialis muscle at 7, 21, and 38 days of age. Histological techniques were employed to evaluate muscle fiber structure, connective tissue thickness, and glycogen distribution. Muscle fiber area, bundle area, and connective tissue thickness peaked at 38 days and were lowest at 7 days. PAS staining intensity progressively increased with age, suggesting greater glycogen accumulation in older broilers. Quantitative real-time PCR (qPCR) was performed to analyze the mRNA expression levels of MYF5, MYOG, and MYH7. At 7 days, MYF5 showed the highest expression, while MYH7 had the lowest. At 21 days, no significant differences in gene expression were detected. However, at 38 days, MYOG exhibited the highest expression, while MYF5 was at its lowest level. These results underscore the dynamic involvement of muscle regulatory genes in iliotibialis muscle development. The results suggest a correlation between gene expression changes and muscle fiber adaptation during growth, emphasizing the importance of MYH7, MYF5, and MYOG in regulating muscle composition in broiler chickens.
Keywords | Broiler chicken, Iliotibialis muscle, Glycogen, MYF5, MYH7, MYOG
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July 2025
Adv. Anim. Vet. Sci., Vol. 13, Iss. 7,
