Nutritional muscular dystrophy production and pectoral muscle 5'-nucleotidase activity in the chick

Graduation date: 1965In an attempt to find a laboratory species which develops an\ud experimental myopathy similar to white muscle disease (WMD) in\ud lambs, comparative studies of nutritional muscular dystrophy of\ud chicks were initiated. This condition was grossly visible as white\ud striations running parallel with the fibers of the pectoral muscles and\ud was routinely produced with a diet containing 15 percent casein and\ud 10 percent gelatin as the protein source. Maximum incidence and\ud severity were observed at four weeks of age.\ud Feeding experiments indicated that selenium supplementation\ud was not as effective in prevention of the symptoms as in lambs and\ud that vitamin E was more effective. Selenium addition at one ppm did\ud not reduce the incidence of lesions as had been previously reported\ud by other workers. A definite synergism between vitamin E and\ud selenium was demonstrated. Neither vitamin E supplementation at\ud 2.5 mg per kg diet nor selenium as sodium selenite at one ppm appreciably\ud reduced the incidence of dystrophy but a combination of these\ud two treatments reduced the occurrence of the syndrome by more than\ud 50 percent. A complete prevention of white striations was not obtained\ud with the combined treatment.\ud The activity of 5'-nucleotidase was not elevated in the\ud dystrophic pectoral muscle as has been reported for lamb tissue.\ud The specific activity (μM P[subscript i]/mg N/hr) of the enzyme was found to be\ud very low in both normal and degenerated muscle. Development of\ud assay conditions is described. The routine assay of dystrophic\ud versus non-dystrophic tissues was carried out at pH 8.9 in 0.25 M\ud glycine buffer. The probable 5'-nucleotidase activity was calculated\ud by subtracting the μmoles of phosphorus liberated from p-nitrophenyl\ud phosphate from that liberated from adenosine-5'-monophosphate\ud after one hour incubation at 38°C.\ud The results did not indicate that the myopathies which occur\ud in the lamb and the chick are the same or similar