ADDITIONAL VITAMIN-E REQUIRED IN MILK REPLACER DIETS THAT CONTAIN CANOLA OIL

It is known that ingestion of oils containing polyunsaturated fatty ac ids (PUFA) of the n-3 and n-6 series results in a high degree of unsat uration in membrane phospholipids which in turn may increase lipid per oxidation, cholesterol oxidation, free radical accumulation and membra ne damage. Vitamin E is a powerful inhibitor of lipid peroxidation ind uced by free radical damage to cell membranes and is an essential comp onent of milk replacers. In the experiments reported here, neonatal pi glets raised on canola oil based milk replacer diets supplemented acco rding to NRC regulations, and with an alpha-tocopherol (mg) to PUFA (g ) ratio of 0.49:1, had low alpha-tocopherol levels in their tissues. D epending on the quantity of iron administered, the piglets showed sign s of vitamin E deficiency which ranged from acute, with high mortality , to mild, with only microscopic evidence of hepatocyte dissociation. Piglets raised on a soybean oil based milk replacer diet, supplemented with the same amount of a-tocopherol, and with a ratio of alpha-tocop herol to PUFA of 0.21:1, showed no signs of vitamin E deficiency and h ad significantly higher tissue levels of vitamin E than the piglets ra ised with the canola oil milk replacer. The factor(s) present in canol a oil which increased the demand for vitamin E are unknown. Copyright (C) 1997 Elsevier Science Inc.