Physicochemical and histochemical characteristics of bovine longissimus lumborum muscle defected as muscular steatosis (massive adipocyte infiltration).

Abstract

To understand muscular steatosis observed in beef carcasses, physicochemical and histochemical characteristics were compared between abnormal (massive fatty replaced) and normal regions of beef striploin. Fat content in the abnormal region (48.02%) was approximately twice than that in the normal region (22.01%). However, fatty acids did not show significant (P\xa0>\xa00.05) differences in their compositions between the two regions. Tenderness was significantly (P\xa0<\xa00.05) higher in the abnormal region. However, other meat quality traits were not significantly (P\xa0>\xa00.05) different between the two regions. Massive accumulation of adipocytes was accompanied by muscle fiber atrophy regardless of muscle fiber types. Without a change in total muscle fiber density, oxidative fiber composition was significantly increased, whereas glycolytic fiber composition was decreased (P\xa0<\xa00.05). These findings suggest that adipogenic transdifferentiation and muscle fiber type switching can occur within the muscle due to muscular steatosis.