[Histomorphometric study of the superficial pectoral muscle of the turkey. Relationship with the meat discoloration syndrome].

Abstract

Scallop discoloration affects about 30% of turkey carcasses, causing important economic losses. Histological and histomorphometric analyses of the superficial pectoral muscle were performed in order to show distinctive aspects of discolored scallops and predictive criteria for the phenomenon. Pectoral muscles of live male turkeys were biopsied 8 d before slaughter. Twenty four h after slaughtering, the same animals were classified into 2 distinctive classes by reflectometry (pale and dark muscles) and muscle samples were collected in each group. Superficial pectoral muscle was totally composed of type IIB, fast switch and glycolytic fibers. Pale and dark muscles exhibited no significant differences 8 d before slaughtering, but glycogen level was higher in pale muscles 24 h after slaughtering. These results do not support the current hypothesis of accelerated glycolysis and low ultimate pH to explain the meat discoloration syndrome in turkeys.