Myofibrillar Protein Profile of the Breast Muscle in Turkeys as a Response to the Variable Ratio of Limiting Amino Acids in Feed

Abstract

The effects of the different dietary levels of Arginine (Arg) in low- and high-methionine (Met) diets on the meat quality and myofibrillar protein profile of breast muscles from turkeys were determined. The experiment had a completely randomized 3 × 2 factorial design with three levels of Arg (90%, 100%, and 110%) relative to the dietary Met levels (30% or 45%). At 42 days of age, eight turkeys from each treatment were sacrificed; the meat pH value was measured at 48 h post-slaughter, and meat color was measured according to the CIE L*a*b* system. The SDS-PAGE method was performed to investigate the myofibrillar protein profile of the breast muscle. The analysis of variance showed a significant effect of the Arg or Met dietary levels on the color parameter b* and the profile of myofibrillar proteins in muscles. The results of the cluster analysis of the myofibrillar protein profile showed that, with a high level of Arg (i.e., 110%), the level of Met 35% or 45% was less important. It can be concluded that the increase in the share of Arg and Met in the diet of turkeys increases the content of some myofibrillar proteins (actinin, desmin, actin) and reduces degradation during the post-slaughter proteolysis of proteins that are considered tenderization indicators.