Biochemical and transcriptomic analyses of two bovine skeletal muscles in Charolais bulls divergently selected for muscle growth

This work aimed to investigate the consequences of muscle growth selection on muscle characteristics. An oxidative muscle (Rectos abdominis, RA) and a glycolytic one (Semitendinosus, ST) were studied in two groups of six extreme young Charolais bulls of high or low muscle growth. Mitochondrial activity was lower in muscles of bulls with high muscle growth. Transcriptomic studies allowed the identification of putatively differentially expressed genes. The differential expression between genetic types of two genes in RA (a heat shock protein and a thyroid receptor interacting protein) and of seven genes in ST (including LEU5, tropomyosin 2, and sarcosin) was confirmed by different statistical approaches or Northern blot analysis, as well as the differential expression of five genes (including PSMD4 and DPM synthase) between RA and ST. Both biochemical and transcriptomic results indicate that selection on muscle growth potential is associated with reduced slow-oxidative muscle characteristics. Further studies are required to understand the physiological importance of genes whose expression is changed by selection. (c) 2005 Elsevier Ltd. All rights reserved.