Effect of dietary linseed oil on pig hepatic tissue fatty acid composition and susceptibility to lipid peroxidation

The effect of linseed oil and a-tocopheryl acetate on fatty acid composition and susceptibility to oxidation in pig liver was studied. The a-tocopherol content of liver from pigs fed diets supplemented with alpha-toeopheryl acetate (200 mg/kg feed) was significantly greater (P < 0.001) than that of liver from pigs receiving a basal diet of 20 mg/kg feed. The concentration of C12:0, C16:0, C18:0 and total saturated fatty acids was higher in liver lipids from pigs fed the control diet than in the other groups (P < 0.05). No effect of dietary linseed administration was observed on monounsaturated fatty acid concentration. Adding linseed oil to pig diets either as the only source of dietary fat or in combination with olive oil produced a higher (P < 0.0001) C18:3 (n-3), C20:4 (n-3) and C22:5 (n-3) concentration in liver lipids. However, no significant effect of dietary treatment was observed on 020:5 (n-3) and C22:6 (n-3). For C20:4 (n-3), a marked effect of dietary linseed concentration was observed, while for C22:5 (n-3) there were no differences between pigs receiving a moderate or a high dietary level of linseed oil. Oxidation was higher in hepatic tissue homogenates from pigs fed linseed oil-enriched diets (P < 0.05), but 200 mg/kg dietary a-toeopheryl acetate supplementation reduced oxidation, reaching similar values to those of the control group. (C) 2002 Elsevier Science Inc. All rights reserved.