Alcohol-induced congestive cardiomyopathy in adult turkeys: effects on myocardial antioxidant defence systems.

The effects of chronic intake of dietary alcohol upon left ventricular function, activities of myocardial antioxidant enzymes, reduced glutathione (GSH) content and lipoperoxidation (measured as the formation of diene conjugates and lipid-soluble fluorescence) were studied in adult domestic Nicholas turkeys. The non-invasive evaluation of left ventricular function by echocardiography revealed an impaired contractile function (the calculated fractional shortening values were 31.1 +/- 4.1% in the alcoholic group and 38.8 +/- 4.4% in the controls) and dilatation of the heart in the alcoholic birds. The changes in the non-invasive parameters of the left ventricle indicate that the adult Nicholas turkey developed congestive cardiomyopathy secondary to the ingestion of ethanol. In the hearts of normal adult turkeys, high GSH content (2.39 +/- 0.25 mumol/g wet weight) and superoxide dismutase activity were found, as compared to other animals, indicating the relatively higher development of antioxidant defence systems. Compared to the controls, significant increases were noted for all the antioxidant enzymes investigated (superoxide dismutase, catalase and glutathione peroxidase) and a moderately significant decrease in the GSH content was found in the left ventricle of alcoholic birds. The changes in GSH concentration and antioxidant enzyme activities might indirectly indicate some involvement of free radicals in the pathogenesis of ethanol-induced myocardial lesion. However, the levels of in vivo lipoperoxidation in the alcoholic birds did not significantly vary from those of control turkeys. Based on these findings, it appears that the reactive oxygen radicals may play a less important role in the pathogenesis of alcohol-induced cardiomyopathy in turkeys--probably due to the higher development of myocardial antioxidant defence systems.