Muscle characteristics from young bulls of different beef breeds

Jurie, Catherine,; Picard, Brigitte,; Micol, Didier,; Listrat, Anne; Kammoun, Malek; Hocquette, Jean-François,

Muscle characteristics from young bulls of different beef breeds

2011

In the framework of the EU ProSafeBeef project, the aim was to determine (1) the contractile and metabolic properties and (2) the total and insoluble collagen contents of two muscles Longissimus thoracis (LT) and Semitendinosus (ST) of 74 young bulls from three breeds: Aberdeen Angus (AA), Limousine (Li), Blonde d’Aquitaine (BA) slaughtered at 17 months of age. Activities of glycolytic (Lactate dehydrogenase, LDH) and oxidative enzymes (Isocitrate dehydrogenase, ICDH; Citrate synthase, CS; Cytochrome-c oxidase, COX) were measured. Contractile properties were determined by electrophoretic separation and densitometric quantification of the proportions of the different myosin heavy chain (MyHC) isoforms. All the data were analyzed by using GLM procedure of SAS. The results demonstrated that muscles from AA bulls have a higher oxidative metabolism (ICDH and COX) associated with a higher proportion of MyHC I and IIa (P<0.001). On the contrary, muscles from Li and BA bulls have a higher LDH activity (P<0.001). The proportion of fast MyHC isoforms (IIx and IIb) was the highest in BA muscles. In addition, both total and insoluble collagen contents were higher in muscles from AA than in those from Li and BA bulls (P < 0.001). These data illustrated some particularities of AA muscles opposite to those of Li and BA in accordance with the fact that Angus is an early maturing breed producing marbled beef.

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