Dr. Casey Owens, Professor of Poultry Science at the University of Arkansas, reviewed the current status of pectoral myopathy at the 2022 IPPE. The condition appears in mild form as white striping but progresses to woody breast. Myopathy is invariably associated with high-weight broilers and is genetic in origin. The pathogenesis has been extensively studied at the histological level, suggesting that selection for accretion of muscle tissue has resulted in a disproportionate level of vascularization, possibly extending from late incubation, but certainly through early growth.
As with all emerging problems in the broiler industry, there is an inevitable scramble to find a quick fix and to market a therapeutic product. A variety of nutrient supplements have been evaluated including enzymes, antioxidants, trace minerals and vitamins administered both in ovo and in diets without showing any significant preventive effect.
Reducing growth rate by modifying amino acid composition of diets may be ameliorative, but at a cost in live mass. It is evident that until a genetic solution is implemented, complexes producing high-weight birds for the tray-pack market will have to compromise on live bird parameters to achieve optimal breast yield at a quality consistent with market demand. Dr. Owens stressed the need to adjust dietary specifications and harvest programs to produce least-cost saleable product of acceptable quality to optimize profit.