Wooden breast (WB) continuous to be the main syndrome affecting the meat quality of broiler chickens. Significant advances have been made in understanding the myopathy’s cellular, histological, metabolic, and physiological effects.
The onset of this muscle metabolic disorder has been described, but the specific etiologies or factors that trigger the problem are still unclear.
We will review some recent research findings indicating that myopathies are related to particular changes in metabolic pathways.
However, linking the metabolic disorders with nutritional modifications to mitigate WB incidence has not been very successful. These facts give an idea of the complexity to solve the WB issue and indicate that better comprehension of all findings is vital to design strategies to mitigate this myopathy.
This article attempts to summarize the new conclusions and how they are related to previous results and practical observations.
THE MUSCLE TISSUE AND MEAT IMPLICATIONS
Let’s start understanding the histological modifications observed in WB myopathy.
There is fibrosis, re-assembling and increase in extracellular matrix proteins, especially collagen type I and III, proteoglycan, and glycosaminoglycans.
The muscular fibers of affected fillets have variable sizes.
Many muscle fibers are too large compared to normal muscle and have permanent contraction or necrosis.
There is interstitial inflammation and frequently mononuclear cell infiltration, especially near small veins.
Inflammation processes near the muscle’s vascular system reduce oxygenation, increase oxidative stress, and muscle cell death.
The lesions may be observed in some individuals in the first week of age.
Some reports have shown similar histological lesions at hatch.
The increased fat infiltration, fibrosis, and collagen changes cause the white strips, paler appearance, and more rigid texture typical of the WB.
The hardness is more evident in the breast muscle’s cranial region, but it occasionally extends throughout the muscle.
A good description of the severity of the pathology with all histological findings is presented in Figure 1.
Figure 1. Broiler chicken Pectoralis major showing the WB myopathy scores, 1 – 4.A gradual progression in the diseased tissue can be observed in the images. Lesions consist of muscle fiber swelling, necrosis, degeneration, regeneration, and lymphocytic vasculitis. Diseased muscle fibers become separated and connective tissue develops around the fibers and betwee...
