Effect of cattle breed on muscle protein quality

The aim of the study was to compare the muscle protein quality in the m. longissimus, pars thoracis of bulls of the Aberdeen Angus (AA) and Czech Fleckvieh (CF) breeds reared under identical conditions within an extensive pasture-based system. The CF breed exhibited a higher crude protein content (887 ± 87.4 g/kg of dry matter) compared to AA (812 ± 59.3 g/kg of dry matter); P ≤ 0.05. A higher content of non-essential amino acids was recorded in CF (390 ± 37.9 g/kg of dry matter) compared to AA (364 ± 44.5 g/kg of dry matter); P ≤ 0.05, as well as higher contents of essential amino acids (CF 406 ± 38.9 g/kg of dry matter, AA 382 ± 41.0 g/kg of dry matter; P ≤ 0.05) and total analysed amino acids (CF 796 ± 74.8 g/kg of dry matter, AA 746 ± 82.7 g/kg of dry matter; P ≤ 0.05). Breed-related differences were observed in the content of most analysed amino acids (P ≤ 0.05), except for tyrosine and phenylalanine, for which no effect of breed was found (P > 0.05). Lysine showed the highest content among essential amino acids (AA 73.4 ± 8.23 g/kg of dry matter, CF 76.6 ± 8.87 g/kg of dry matter; P ≤ 0.05), while glutamic acid was dominant among non-essential amino acids (AA 109 ± 14.4 g/kg of dry matter, CF 119 ± 12.5 g/kg of dry matter; P ≤ 0.05). The ratio of essential to non-essential amino acids (EAA/NEAA) did not differ between breeds (AA 1.05 ± 0.08, CF 1.04 ± 0.05; P > 0.05). The results indicate that cattle breed affects the content of crude protein and the content of most analysed amino acids in the muscle tissue of AA and CF breeds; however, the EAA/NEAA ratio remains unaffected by breed.