Effectiveness of alpha-tocopherol and selenium supplements in preventing lupinosis-associated myopathy in sheep.
OBJECTIVE
To compare the effectiveness of combined selenium and alpha-tocopherol acetate treatments in preventing lupinosis-associated myopathy in sheep.


METHODS
Measurement of plasma muscle and liver enzymes, and histopathological examination of muscle and liver in the treatment groups.


METHODS
The treatments were: subcutaneous injections of selenomethionine and vitamin E (sc(SeM+E)), an intraruminal selenium pellet and oral doses of vitamin E and intramuscular injections of selenomethionine combined with either oral doses of vitamin E (imSeM+orE) or intramuscular injections of vitamin E in an oily carrier. Another group received no supplements, while a control group was given selenium pellets on day 0 and fortnightly oral doses of vitamin E from day 0 to 72. To produce lupinosis-associated myopathy, the sheep were fed a diet low in vitamin E and given repeated injections of a crude extract of Diaphorthe toxica. Groups sc(SeM+E) and imSeM+orE were stressed by dosing with protected polyunsaturated fatty acids from day 56 onwards.


RESULTS
Lupinosis-associated myopathy was induced in all unsupplemented sheep. In these sheep the storage of Se increased and that of vitamin E decreased. The subcutaneous treatment was highly effective in preventing lupinosis-associated myopathy and also produced the highest vitamin E concentrations in plasma and liver. Supplemental vitamin E was more efficacious than supplemental Se. Concentrations of vitamin E in the livers of sheep given intramuscular vitamin E were higher than expected based on plasma concentrations. Oral doses of vitamin E proved the least effective method of increasing concentrations in liver. Lupinosis did not affect Se concentrations in liver or muscle.


CONCLUSIONS
The sc(SeM+E) treatment is highly effective in preventing lupinosis-associated myopathy but needs to be further assessed when selenium and vitamin E are both limiting in the diet.
Smith
G M
GM
Animal Health Laboratories, Agriculture Western Australia, South Perth.
Allen
J G
JG
D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000008:administration & dosage*; D001284:Atrophy / Q000662:veterinary; D007273:Injections, Intramuscular; D007279:Injections, Subcutaneous; D008099:Liver / Q000473:pathology; D009135:Muscular Diseases / Q000517:prevention & control / Q000662:veterinary*; D009748:Nutrition Disorders / Q000517:prevention & control / Q000662:veterinary*; D012643:Selenium / Q000008:administration & dosage / Q000172:deficiency*; D012756:Sheep; D012757:Sheep Diseases / Q000517:prevention & control*; D024505:Tocopherols; D014810:Vitamin E / Q000008:administration & dosage / Q000031:analogs & derivatives*; D014811:Vitamin E Deficiency / Q000517:prevention & control / Q000662:veterinary*; D024502:alpha-Tocopherol / Q000031:analogs & derivatives*
D000975:Antioxidants; D014810:Vitamin E; D024502:alpha-Tocopherol; D012643:Selenium; D024505:Tocopherols