The US Poultry & Egg Association (USPOULTRY) and the USPOULTRY Foundation announced on July 18, that a research project at North Carolina State Univ., Raleigh, N.C., concluded that wooden breast condition has existed in broiler chickens since the 1950s. The project, led by John Barnes, Ph.D., took a closer look at the onset of wooden breast lesions in three breeds of modern broilers as well as a line of broilers from the 1950s. While the lesions were discovered to be more severe in modern day broilers, the condition was evident in the 1950s line as well and the microscopic evidence of the lesions in the breast muscles were present in all lines of the broilers at two weeks of age. Researchers also proposed a new name for this condition — Superficial Pectoral Myodegeneration and Sclerosis: Broiler Breast Myopathy (BBM).
The research was financed by a foundation gift from Ozark Mountain Poultry and is part of the USPOULTRY’s comprehensive research program encompassing all phases of poultry and egg production and processing.
According to the research summary, while broiler breast myopathy begins to develop within the first two weeks of age in chickens, by three weeks, some birds have marked muscle degeneration and most develop muscle disease by four weeks.
“Scar tissue replaces damaged muscle, which contributes to muscle hardness (wooden breast). Additional space from lost muscle can fill with fat, which helps explain the relationship between BBM and ‘white striping’.” Muscle hardness plateaus at about two months and remains until about 13 weeks of age, according to the research.
Researchers detected a correlation between the inflammation of small veins in the breast tissue and the severity of muscle damage. “The significance of this change is unknown, but it is reasonable to assume that blood flow to the muscles is affected. No cause for the vascular damage is known, but a virus has been isolated from affected muscles,” the summary states.
Looking closer at the role of the virus in BBM is the subject of a current research project by USPOULTRY. More information on this and other research projects by the association is available at: www.uspoultry.org.