Histopathology of hereditary muscular dystrophy of the domestic turkey (Meleagris gallopavo)

The histopathology of hereditary muscular dystrophy was studied in homozygous dystrophic turkeys of various ages. Lesions were severe at ten weeks of age but absent at seven weeks or less. Lesions at ten weeks consisted of variation in fiber size and contour with acute necrosis of individual muscle fibers. Myopathic characteristics were similar at 16 and 24 weeks but with fewer dystrophic fibers and slower fiber destruction. Fat deposition was mild at 24 weeks and there were disseminated foci of endomysial proliferation in dystrophic muscle at 16 and 24 weeks. Pectoral and alar muscles were dystrophic but no lesions were detected in gastrocnemius muscle myocardium, central and peripheral nervous system tissue or visceral organs. Mean diameters and nuclear numbers of muscle fibers were significantly less in pectoral muscles of dystrophic turkeys than in controls and did not increase significantly from ten to 24 weeks of age as did controls.