The Growth and Composition of Skeletal Muscle in the Chicken

Abstract

AN INCREASE with age in the con--**• centration of non-protein nitrogen, as well as protein, in the pectoral muscle of the chicken has previously been reported by Dickerson (1960) and by Simmonds et al. (1964). However, the nonprotein nitrogen fraction is comprised of a number of substances of differing biological function, such as amino acids, peptides, creatine and purines, and it is to be expected that the pattern of change of these substances will differ. This paper describes a study of the variation with age of the concentration of certain non-protein nitrogen fractions in chicken muscle. In the first experiment estimations were made of total nitrogen, protein nitrogen, non-protein nitrogen, creatine (including phosphocreatine) and ammonia in the pectoral muscle. In the second experiment the dipeptides, anserine and carnosine were estimated in the pectoral and gastrocnemius muscles. MATERIALS AND METHODSTwo strains of New Hampshire chickens were used, one for each experiment. Both strains had been maintained as unselected closed flocks for a number of generations. Groups of chickens were sacrificed at 0, 4, 8, 16 and 32 days of age and also at about six months (adults). In the NEWS AND NOTES (continued from page 455) in food sciences, and serve as the central vehicle of communication at Purdue for students, staff, industry and government agencies with an interest in food sciences and related areas.