EFFECTS OF VITAMIN E OR ETHOXYQUIN AND RUMEN DEVELOPMENT UPON MUSCULAR DYSTROPHY IN LAMBS

Abstract
In a 2 × 3 factorial procedure, torula yeast-lard (10%) diets supplemented with either vitamin E (68 IU/kg) or ethoxyquin (0.01 or 0.1%) were fed to 27 1-week-old crossbred lambs to promote or prevent rumen development. After a 12-week trial period, myopathy was apparent in 100, 25, and 0% of lambs fed diets supplemented with ethoxyquin (0.01, 0.1%) or vitamin E, respectively. Seven lambs died prematurely but only one of these deaths was attributed to myopathy. Rumen development did not affect the occurrence of myopathy but reduced (P < 0.05) the elevation of plasma glutamate-oxaloacetate transaminase (GOT) in myopathic lambs during the trial. Vitamin E improved (P < 0.05) average daily gain of lambs (mean 142.0 g) compared with 0.01% ethoxyquin (0.1% ethoxyquin intermediate) and rumen development had no apparent effect. Tissue ethoxyquin levels reflected amounts fed and were unaffected by rumen development. Rumen development generally reduced the content of polyunsaturated fatty acids in muscle phospholipids and adipose tissue, whereas vitamin E or ethoxyquin specifically affected linoleic acid.