Differential Myf5 and Myf6 expression and muscle fiber traits in Angora, Hair, Honamlı, and Kilis goats.

The present study was conducted on specific skeletal muscles of six weaned male kids from each of the Angora, Hair, Honamlı, and Kilis goat breeds. The relationships between the expression of myogenic factor 5 (Myf5) and myogenic factor 6 (Myf6) genes and muscle fibre characteristics were analysed. Muscle samples from the longissimus dorsi (LD) and semitendinosus (ST) were collected from six 90-day-old weaned male kids of each breed. Muscle fiber characteristics were assessed through histochemical staining, while expression levels of Myf5 and Myf6 genes were quantified using real-time PCR. Total RNA content in the LD and ST muscles was significantly higher (p < 0.05) in Honamlı kids compared to those of the other breeds. Similarly, the expression of Myf5 gene in Honamlı kids was significantly higher (p < 0.05) than that observed in kids from the other breeds in LD muscle. Conversely, in the ST muscle, Hair kids exhibited a significantly lower expression of Myf5 (p < 0.05) when compared to both Honamlı and Kilis kids Additionally, Kilis kids demonstrated a significant reduced expression of Myf6 gene (p < 0.05) relative to the other breeds. The highest expression levels of the Myf6 gene (p < 0.05) were detected in the ST muscle of Honamlı and Angora kids, significantly surpassing those observed in Hair and Kilis kids. Moreover, significant correlations (p < 0.05) were observed among Myf5 and Myf6 gene expression levels and various muscle fiber characteristics differing across breeds. The results of this study underscore the pivotal role of these myogenic regulatory factors in muscle development, offering insights into the molecular mechanism driving breed-specific muscle growth. This association between gene expression and muscle phenotype could have profound implications for targeted breeding programs aimed at optimizing muscle traits in livestock species.