Plasma indicators of muscle damage in a model of nutritional myopathy in weaner sheep

Abstract

Subclinical nutritional myopathy was induced in 5-month-old sheep by feeding them a diet low in vitamin E and selenium. Subsequently clinical myopathy was induced by dosing with protected polyunsaturated fatty acids. Plasma activities of creatine kinase (CK), pyruvate kinase, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase and aldolase, enzymes of muscle origin, all remained above their reference ranges in clinically affected sheep, but fluctuated widely. Similar fluctuations occurred in subclinically affected animals, resulting in some activities being within the reference ranges and 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 in the vastus lateralis (VL), but not the vastus intermedius (VI) or the tensor fascia lata (TFL) muscles. AST was the most highly correlated with damage in VI and VL. In two clinically affected sheep successfully treated with an oral dose of alpha-tocopherol acetate all enzymes decreased steadily to within their reference ranges, at rates probably related to their plasma half-lives. These results suggest that measurement of plasma CK activity would be useful in monitoring recovery of treated sheep.

Changes in arginase activity and AST enzyme levels in the cardiac andskeletal muscle and liver of lambs with white muscle disease

“…Various studies have reported that serum and/or plasma AST values increase in lambs with WMD (16,17). In this study, a significant decrease in AST levels in the cardiac muscle was found in the WMD group compared to the control group.…”

Values of Blood Variables in Calves

“…The activity of CK could be increased also after effort, long-lasting lying of the animal or convulsions. Miopathias as the consequence of vitamin E and Selenium deficiency which usually appear in veal animals (calves, lambs), sometimes also in adult animals, cause increased activity of CK (Smith et al, 1994).…”

Seasonal variation of glutathione peroxidase, CK and AST in sheep in a low-selenium region

“…The AST evolution was different, showing the lowest activity during the summer, just when the GSH-Px activity was at the minimum value. This behaviour confirms that AST is not as specific as CK as marker of muscle damage, since it is widely distributed in different organs and tissues (Blood et al, 1992;Smith et al, 1994). The inverse changes of GSH-Px-CK activities could also indicate that this later enzyme may be used as a good monitor of muscle damage.…”

“…The inverse changes of GSH-Px-CK activities could also indicate that this later enzyme may be used as a good monitor of muscle damage. In this sense different authors have showed that CK is one of the most specific parameters of acute muscle damage in all species, reporting also that CK activity was highly correlated to muscle damage (Blood et al, 1993;Braun et al, 1993;Smith et al,1994). CONCLUSIONS GSH-Px activity registered during the summer, within a deficient range, indicates that the animals were constantly at risk from selenium-deficiency diseases.…”