22.09.2021: Fat and fatty tissue are a normal part of most pork cuts. A recent study by Vetmeduni, however, shows that a pathological muscular disorder in which muscle tissue is replaced by fat also occurs in Austrian slaughter pigs. Why some pigs develop this disorder, known as fatty muscular dystrophy, remains unclear.

For the veterinarians responsible for meat inspection in slaughterhouses, abnormalities are a common occurrence. A veterinarian responsible for meat inspection at a slaughterhouse in the Austrian federal state of Styria observed that the gluteal muscles in two different slaughter pigs from the same farm had been infiltrated and partially replaced by fat. These muscles were sent for further diagnostics to Vetmeduni´s  University Clinic for Swine.

Fatty muscular dystrophy – a common disease among slaughter pigs

A recently published study reports on the histopathological examinations of the two muscle samples and describes the results of a survey performed among meat inspecting veterinarians to gain further insights into muscular abnormalities in slaughter pigs in Austria. According to the study’s first author, Lukas Schwarz from the University Clinic for Swine at Vetmeduni, the study shows that this muscular disorder is not at all rare: “The survey to determine the prevalence of fatty muscular disorders of pork revealed that this phenomenon is most frequently observed in Styria, but also occurs in Upper Austria and Lower Austria. Fatty muscular dystrophy among pigs therefore seems to be neither uncommon nor rare.”

Cause of muscular disorder remains unclear

The muscular disorder could have several causes, researchers say. In 2013, a pig in Japan was for the first time diagnosed with a disease comparable to Becker muscular dystrophy (BMD), a muscular disorder that also affects humans. The results of an immunohistochemical examination of the two Austrian pigs showed that the disease is associated with a disturbance of dystrophin expression. Dystrophin is a critical structural protein necessary for proper muscle function. As the researchers can only speculate about the causative mechanisms of the fatty muscular dystrophy, they consider an in-depth analysis to be indicated in order to clarify the prevalence of fatty muscular dystrophy not only in the Austrian pig population but also in the pig population worldwide.

Further research urgently needed

According to the researchers, further studies are now urgently needed to develop strategies against fatty muscular dystrophy and other muscular diseases. The scientists will formulate several recommendations to further clarify the underlying causes of this condition. “Firstly, it needs to be clarified whether the cause is environmental or genetic. And if it is genetic, it would be crucial to decipher the underlying genomic architecture. Furthermore, it would be important to investigate the prevalence of the disease among different pig breeds, not only in Austria but also worldwide, to be able to make reliable statements about the spread of the disease,” says last author Andrea Ladinig, head of the University Clinic for Swine at Vetmeduni.