Determinazione degli acidi grassi e della vitamina E nel muscolo di vacche Piemontesi affette da miopatia lipomatosa

Abstract

Lipomatous myopathy is a degenerative muscle disease reported in Piedmontese cattle, characterized by the substitution of muscle cells with adipose tissue. The pathogenesis of this myopathy is still poorly understood, most likely its origin is multifactorial, with genetic and nutritional factors contributing to its development. In this work Authors performed histological and biochemical analyzes on samples taken from four different muscle types (vastus lateralis, biceps brachii, cutaneous trunci and cutaneous colli) from Piedmontese cattle, seven healthy animals and seven with lipomatous myopathy, aged fourteen to nineteen months. The animals were reared under the same environmental condition  and fed at the same energy and protein level without vitamin E supplementation. None of the animals showed clinical signs of muscular disease and all were in an excellent state of nutrition. The seven affected animals were identified by macroscopic examination for the presence of infiltration of adipose tissue in multiple or individual muscles. Histological analysis of the tissue with lipomatous myopathy revealed infiltration of adipose tissue of various distribution and severity. Necrosis and non suppurative inflammatory cells were also seen. Furthermore, proliferation of connective tissue and non-specific myopathic changes, were present too. Biochemical analyzes of pathological tissue showed an increase in fatty acid content, in particular for monounsaturated fatty acids (MUFA), and a marked decrease in vitamin E content compared to healthy tissue. As the activity of the stearoyl-CoA desaturase (SCD), a rate-limiting enzyme in the biosynthesis of monounsaturated fatty acids, has recently been shown to be a critical control point in the regulation of skeletal muscle lipid metabolism, and the desaturation indices for 18:0 and 16:0 fatty acids are considered indirect indicators of SCD, Authors calculated the mathematical indices for Δ (9)-desaturase C16 activity and for Δ (9)-desaturase C18 activity in total lipid extracts.  As compared with the controls, in pathological samples the desaturation index (18:1Δ9/18:0 ratio) was significantly higher. Currently, it is not possible to predict to what extent these changes can influence the organoleptic, technological, and nutritional characteristics of meat from cattle with lipomatous myopathy. Further study is needed to understand how these changes relate to meat quality and the pathogenesis of lipomatous myopathy.