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The effects of partial replacement of dietary polyunsaturated fatty acid (PUFA) with monounsaturated fatty acid (MUFA) on fatty acid profiles of subcutaneous and intramuscular fat and rheological properties of fat were studied in heavy pigs. No effect of dietary fat was observed on total saturated fatty acids proportion in outer and inner backfat layers or intramuscular neutral and polar lipids. The partial substitution of dietary PUFA by MUFA produced a rise in MUFA of intramuscular polar lipids (p < 0.01) but neutral lipids were not affected. Moreover, it also decreased (p < 0.01) the n-6 proportion of outer and inner backfat layers and intramuscular polar lipids, but no effect was observed for the n-6 in the intramuscular neutral lipids. No significant effect of dietary fat treatment was observed on n-3 fatty acids in outer and inner backfat layers, but the partial substitution of PUFA by MUFA increased (p < 0.01) the n-3 proportion of intramuscular lipid fractions and the consequent decreased in the n-6/n-3 ratio in all lipid location. Significant effects of dietary vitamin E were observed on springiness, cohesiveness and adhesiveness of backfat inner layer. However, consistency was not affected by dietary fat. Further research is needed to establish the effects of different ranges of dietary oil combination in the feeding of heavy pigs.

The objective of this study was to assess the effect of dietary copper and/or vitamin E supplementation on composition and oxidation of M. longissimus in Iberian pigs and to compare it with meat samples from pigs produced extensively and fed with acorn and grass. Grass had the highest alpha-tocopherol content (> 150 mg/kg DM), while acorns had the highest copper concentration (78.1 mg/kg DM). Dietary treatment did not affect copper composition in muscle and no interactions were detected between copper and alpha-tocopherol. The alpha-tocopherol content in muscle from pigs fed diets supplemented with alpha-tocopheryl acetate (100 mg/kg feed) was 1.5 times greater (p < 0.0001) than those from pigs receiving a basel diet. M. longisssimus dorsi from pigs fed extensively had a higher concentration of alpha-tocopherol than those fed in confinement with the basel level of alpha-tocopheryl acetate, but lower values than pigs fed supplemented levels. Total n-3 fatty acids (p < 0.02) and hematin (p < 0.0001) concentrations were significantly higher in muscle from pigs fed extensively than when fed in confinement. Muscle homogenates from Iberian pigs fed in extensive conditions showed significantly (p < 0.02) higher susceptibility to oxidation than those from pigs fed mixed diets. Dietary alpha-tocopheryl acetate supplementation (100 mg/kg feed) significantly (p < 0.05) reduced lipid oxidation of muscle, while dietary copper concentration did not modify susceptibility to lipid oxidation.