Analysis of gene expression in specific muscles of swine and turkey

e meat quality is a result of properties of muscle metabolism and muscle structure at slaughter. Thus, it is a quantitative trait with a large number of genes involved. Moreover, environmental factors are modifying the gene effects at all stages of the ontogenesis. In our approach, we focussed on the expression of a set of genes with potential functions in development and growth of skeletal muscle. This set includes key regulatory factors of muscle cell development and growth as well as genes coding for major structural components of skeletal muscle. In swine, we investigated the expression of a total of 12 genes in M. biceps femoris of newborn piglets by RT-real time PCR. Aim of this investigation was the identification of genes differentially expressed between piglets suffering from a muscular disease (splay leg) and healthy controls. Differences in the expression of several Myosin Heavy Chain (MyHC) isoforms were found only when the animals were assigned to groups with different degrees of pathological alterations in the ultrastructure of the muscle as revealed by electron microscopy. In a second part, the expression of 6 genes was investigated in the M. pectoralis superficialis in different turkey lines. The analyses were done at two different ages at slaughter and the birds were assigned to the groups with normal and poor meat quality, respectively. The expression of the adult isoform of MyHC was significantly increased in Kelly BBB toms at week 12 compared to genotype BUT BIG6. There was also a trend to an increased MyHC and decreased glypican expression in toms with poor meat quality regardless of line and age. In contrast, expression of myostatin and insulin-like growth factor1 showed an age-dependent pattern with increased values at higher ages. The investigations demonstrate that analysis of gene expression contibutes to the understanding of mechanisms involved in development of muscular diseases as well as in poor meat quality.