Degenerative myopathy in turkey breeder hens: a comparative study of normal and affected muscle

Structural alterations in oedematous and apparently normal skeletal muscle of domestic turkey

The morphology and histochemistry of oedematous and apparently normal turkey muscle were compared. Alterations in structural morphology were observed in the majority of the oedematous muscles and in about half the control muscles. Both the pectoralis thoracicus and biceps femoris were affected, with the former to a slightly greater extent. Histological features included proliferated endomysial and perimysial connective tissue, fatty replacement of necrotic areas of muscular tissue, evidence of fibre hypercontraction, necrosis of isolated fibres, shrunk and pyknotic nuclei and infiltration of the walls of blood vessels by mononuclear cells. In affected muscle, the histochemical reactions were weak and/or uniform amongst fibre types. There was no apparent association between the observed structural alterations and the oedematous condition.

Myopathy in brown pelicans (Pelicanus occidentalis) associated with rancid feed

Three adult brown pelicans (Pelicanus occidentalis) were observed to be weak, anorexic and unresponsive to antibiotics, anti-inflammatory drugs, vitamins including vitamin E, and steroids. Blood chemistry revealed high activities of aspartate aminotransferase, creatinine kinase and lactate dehydrogenase. Radiographs of the birds' leg muscles revealed multiple opacities suggestive of calcification; the gross lesions included white streaks in the leg, wing, and heart muscles, and the microscopical lesions consisted of various degrees of degeneration and necrosis characterised by eosinophilia, variations in fibre size, loss of striations, myolysis, mineralisation, and proliferation of mononuclear cells in the skeletal muscles and the myocardium. The levels of heavy metals, selenium and vitamin E in the birds' livers were not abnormal. The level of peroxide in their diet of capelin fish was high, 69 meq/kg, (normal <20 meq/kg) consistent with rancid feed, and the level of vitamin E was very low, 0.5 iu/kg (normal 20 to 30 iu/kg). It was concluded that the myopathy was probably caused by vitamin E deficiency due to feeding the pelicans a rancid diet.

Histopathological and ultrastructural alterations of turkey skeletal muscle

The pectoralis thoracicus and biceps femoris muscles were obtained from 30 18-wk-old Large White turkey males at the time of slaughter. The birds had no observable mobility or postural problems, and the meat appeared normal. Samples were processed for histology, histochemistry, and electron microscopy. Degenerative features were found in muscle from 10 of the 30 birds. Four of the 10 had alterations in both muscles. The degenerative changes included scattered focal necrosis, hypercontraction of muscle fibers, infiltration by mononuclear cells, formation of fibrous tissue scars, and Z-band streaming. These structural alterations appear to be related to muscle ischemia.

Optical characteristics of deep pectoral myopathy in turkey carcasses

When eviscerated turkey carcasses are illuminated with white light from a 100 W lamp in the body cavity dorsal to the sternum, about 90% of carcasses with deep pectoral myopathy can be detected subjectively. With this method, subjective detection is more reliable than photometric detection. When a fiber-optic probe is placed in direct contact with a lesion, the absorbance spectrum of reflected light is radically different to the spectrum from normal muscle, and three types of lesions can be identified (red-purple, green, and yellow). However, the presence of lesions is masked by even a shallow depth (approximately 1 cm) of normal muscle between the lesion and the probe. A combination of both optical methods might enable carcasses to be inspected without slashing the breast muscles of all the carcasses from flocks of suspect birds, but the whole length of the supracoracoideus on each side would have to be traversed by the fiber-optic probe. For a fiber-optic detection system in the abattoir, the simplest diagnostic characteristic would be the ratio of two wavelengths (480/550 nm). The average ratio for normal muscle was .68. The average ratios for lesions were from 1.17 to 1.38.

Plasma creatine kinase as an indicator of degenerative myopathy in live turkeys

1. Diagnosis for degenerative myopathy of the Musculus supracoracoideus (DMS) in the live bird was attempted from plasma creatine kinase (CK) [EC 2.7.3.2] activities in 70 female turkeys. The blood of each bird was sampled 18 to 20 times over an age span of 16 to 79 weeks. 2. DMS incidence was 15.7%. 3. After CK values were logarithmically transformed and corrected for bleeding date, 82% of the affected birds had one CK value that deviated 3 or more standard deviations from the mean of other values for the same bird. The results indicate that plasma CK activities can be used to identify affected birds with a high degree of reliability.

Pathology of deep pectoral myopathy of broilers

Deep pectoral myopathy occurred in 39 of 204 apparently healthy and 46 of 146 ill, adult broiler breeders from Poultry Research Centre flocks. Both sexes and two commercial strains were similarly affected. The myopathy was not associated with any disease except pododermatitis. The supracoracoid was the only muscle affected. It was bilaterally involved in 33 chickens. The lesions were grouped macroscopically into three categories: acute oedema progressing to a green necrosis, centrally located cicatrix, and replacement of the caudal region by fibroadipose tissue. Microscopcially the green lesion consisted of necrotic, anucleate muscle fibres devoid of inflammatory cells and surrounded by a fibrous capsule that had a reactive inner border and externally abutted on normal and regenerating muscle or fibro-adipose tissue. Considered with the ultrastructural findings of early loss of glycogen and disintegration of sarcoplasmic reticulum, mitochondria, nuclei and Z lines, these findings indicate that the condition is an ischaemic necrosis. There was no evidence that its primary cause was occlusive vascular lesions. The muscle was able to regenerate unless extensive secondary neurological lesions were present.