Effects of dietary vegetable oil inclusion and composition on the susceptibility of pig meat to oxidation

This investigation was designed to evaluate the effects of the dietary inclusion of vegetable oil and its composition on fatty acid composition and lipid oxidation in pig muscle. Pigs mere given the following diets from 50 kg to slaughter (90 kg): a control diet with no added fat (NF) or diets containing 20 g/kg of sunflower (SUN), olive (OL) or sunflower + linseed (SUN + LIN) oils. Meat from pigs given the SUN + LIN diet showed the highest thiobarbituric acid reactive substances (TBARS) from day 3 of refrigerated storage to the End of the experiment (P < 0.05). The OL group showed the lowest TEARS after 9 days of storage (P < 0.05). Pigs on NF showed intermediate values that were generally closer to those recorded for pigs given the SUN + LIN than the OL diet. By day 9, there was no statistical difference between the NF and the SUN + LIN group. The SUN group also showed intermediate TEARS throughout storage, with no statistical differences compared with the NF group. After 9 days of storage the lowest CIELAB a* value, corresponded to the SUN + LIN group and the highest to the OL group These results indicate similar behaviour to that of lipid oxidation. Meat samples from pigs given the diet not enriched with fat showed greater drip loss than those given the remaining diets (P < 0.05) while there was no significant effect of dietary fat source on water-holding capacity. The inclusion of oils rich in linoleic fatty acids in pig diets modifies muscle fatty acid composition but susceptibility to lipid oxidation does not appear to be increased with respect to that occurring in pigs given diets with no added fat.