The longissimus thoracis muscle proteome in Alentejana bulls as affected by growth path.

Beef production is an important economic activity. In Southern Europe there are two types of beef production systems based on growth paths: continuous (CG) versus discontinuous growth (DG). DG is a traditional system dependent on pasture; whereas in CG animals are supplemented on concentrate feed. We compare the protein abundance profiles of the longissimus thoracis (LT) muscle in CG and DG animals using label-free quantitative proteomics. Twenty three Alentejana male calves (9months-old, 239kg live-weight) were allocated to two feeding regimens. In CG (n=12) production system, animals were fed ad libitum on concentrates plus hay and slaughtered at 18months. In DG (n=11) production system, animals were fed ad libitum on hay from 9 to 15months of age and then the same diet provided to the CG group and slaughtered at 24months. The LT muscle was sampled and protein abundance profiles determined using label-free quantification. We identified 510 proteins, of which 26 showed differential abundance. Several proteins (e.g. Myozenin-2, glyoclythic enzymes and 14-3-3 protein zeta/delta) are proposed as indicators of a more intensive growth path. Myosin binding protein H had higher abundance in the DG group, suggesting it could be associated to discontinuous growth path.