USE OF ALPHA-TOCOPHEROL ACETATE TO IMPROVE FRESH PIG MEAT QUALITY OF FULL-FAT RAPESEED-FED PIGS

Thirty-two pigs were allocated to one of four diets, FFRD0 and FFRD200 , containing full-fat rapeseed (FFR), 150 g/kg [25-50 kg liveweight (L W)], and 250 g/kg (50-90 kg LW), or CD0 and CD200, containing equivale nt quantities of rapeseed meal and 34 g/kg (25-50 kg LW) or 59.2 g/kg (50-90 kg LW) coconut oil and lard (0.5:0.5, w/w). Diets FFRD200 and C D200 were supplemented with 200 mg/kg alpha-tocopherol acetate (ATA). ATA supplementation significantly (P < 0.001) reduced muscle drip loss . The melting point (degrees C) of subcutaneous fat was significantly lowered by FFR (P < 0.001) but increased by ATA supplementation (P < 0 .05). Tissue alpha-tocopherol (AT) concentrations were significantly i ncreased by ATA supplementation. Longissimus dorsi AT concentration wa s positively correlated with AT concentration in subcutaneous fat (r = 0.86) and in plasma at 35 (r = 0.65) and 77 (r = 0.85) days of feedin g (P < 0.001). In both L. dorsi and subcutaneous adipose tissue lipids , FFRD caused a significant (P < 0.001) decrease in the ratio of n-6 t o n-3 fatty acids and a significant (P < 0.001) increase in the ratio of polyunsaturated to saturated fatty acids. AT supplementation signif icantly reduced the susceptibility of L. dorsi and subcutaneous fat to lipid oxidation during storage at 4 degrees C for up to 16 d. For all dietary treatments and storage times, lipid oxidation [mg malondialde hyde (MDA)/kg muscle] was greater in the surface layer (0-2.5 mm) of L . dorsi than below the surface (2.5-5 mm). Oxidative stability of L. d orsi lipids to iron-induced lipid peroxidation was significantly impro ved (P < 0.001) by AT supplementation. Meat from pigs fed FFRD diets w as significantly less stable to iron-induced oxidation (nmoles MDA/mg protein) at the longer incubation periods (100 and 200 min). The susce ptibility of L. dorsi to iron-induced lipid oxidation decreased as the ratio of the tissue concentration of AT to unsaturated fatty acid inc reased.