PLASMA INDICATORS OF MUSCLE DAMAGE IN A MODEL OF NUTRITIONAL MYOPATHYIN WEANER SHEEP

Subclinical nutritional myopathy was induced in 5-month-old sheep by f eeding them a diet low in vitamin E and selenium. Subsequently clinica l myopathy was induced by dosing with protected polyunsaturated fatty acids. Plasma activities of creatine kinase (CK), pyruvate kinase, asp artate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase and aldolase, enzymes of muscle origin, all remained ab ove their reference ranges in clinically affected sheep, but fluctuate d widely. Similar fluctuations occurred in subclinically affected anim als, resulting in some activities being within the reference ranges an d some above, at different times. Plasma malondialdehyde, an indicator of lipid peroxidation, proved of no diagnostic value. Terminal plasma CK activities were significantly correlated with microscopic damage i n the vastus lateralis (VL), but not the vastus intermedius (VI) or th e tenser fascia lata (TFL) muscles. AST was the most highly correlated with damage in VI and VL. In two clinically affected sheep successful ly treated with an oral dose of cl-tocopherol actetate all enzymes dec reased steadily to within their reference ranges, at rates probably re lated to their plasma half-lives. These results suggest that measureme nt of plasma CK activity would be useful in monitoring recovery of tre ated sheep.