Is Meat Quality Affected by the Use of Repartitioning Agents?

The effects of the p-adrenergic agonists (BAA) and somatotropin on livestock species are well documented and have been the topic of discussion at previous conferences (see RMC proceedings 1984, 1985, 1987). These agents markedly alter carcass composition, i.e., they decrease fat deposition and increase muscle mass. The BAA appear to have their greatest effect on muscle hypertrophy, while somatotropin appears to have its greatest effect on fat deposition. Because of the reduction in fat and increased muscle content of carcasses from animals treated with these agents, concerns have been raised about their effects on qualitative properties of the meat. The objective of this review is to summarize the published literature, including abstracts, on the effects of BAA and somatotropin on meat quality of beef, pork and lamb. The data are presented by qualitative trait, species and BAA. Questions such as the following have been asked: Do these agents predispose carcasses to coldinduced shortening? Does the decrease in fat and presumably marbling affect the palatability factors? Because catecholamines stimulate glycogenolysis, do their analogs, the p-agonists, cause DFD or PSE conditions in postmortem muscle? Does the change in muscle protein turnover accounting for the marked hypertrophy affect the enzymes involved in postmortem proteolysis? The connective tissue proteins? These are some important questions, but few answers have been reported in the scientific literature to date.