Fractionation studies on a factor in linseed meal protecting against selenosis in chicks

Growth rate of Single Combe White Leghorn cockerels fed a casein-gelatin-glucose diet was significantly depressed at two weeks when 10 p.p.m. or more selenium was added to the diet. When 20% linseed meal was included in the diet, growth was not reduced with 10 p.p.m. selenium and only slightly reduced with 20 p.p.m. selenium. Including 20% soybean meal failed to modify the toxicity. Levels of 5 and 10% linseed meal were less effective in counteracting selenosis than was 20%. Fractionation studies showed that a protective factor in linseed meal was extracted by methanol and ethanol and was not destroyed by autoclaving. Ashing the ethanol extract destroyed its activity. The factor was readily extracted by chlorform:methanol (2:1) but less effectively by acetone and diethyl ether. Washed chloroform:methanol extract was inactive but the washings contained the factor. Concentrates of the factor were active at less than 1% of the dry matter of the diet. The results of these studies show that linseed meal contains a heat stable, organic, polar factor that modified selenium toxicity in the chick.