Effect of dietary α-tocopheryl acetate on α-tocopherol levels in porcine muscle and on lipid oxidation in pork

Introduction Lipid oxidation is a major contributor to deterioration in meat quality affecting the flavour, colour, nutritive value and safety of meat and meat products (Gray and Pearson, 1987). a-tocopherol functions as an antioxidant in animal tissues by scavenging free radical species which are involved in the initiation and propagation of lipid oxidation (Machlin, 1984). Animal tissue levels of a-tocopherol have been shown to be directly related to the logarithm of dietary vitamin E intake (Bieri, 1972; Chow, 1975; Gallo-Torres, 1980). Studies undertaken in the past to investigate the rate of uptake of a-tocopherol by various animal tissues (Bieri, 1972; Gutcher, 1988) have shown that plasma and liver a-tocopherol levels respond rapidly to changes in dietary a-tocopherol while adipose tissue responds slowly. Other tissues have demonstrated an intermediate response. Previous studies in our laboratory have shown that long-term (10 week) and short-term (2 week) pre-slaughter a-tocopheryl acetate supplementation of pig diets resulted in a significant increase in plasma and muscle a-tocopherol levels in the pig (Monahan, Buckley, Gray, Morrissey, Asghar, Hanrahan and Lynch 1990a; Monahan, Buckley, Morrissey, Lynch and Gray, 1990b). However, the minimum pre-slaughter supplementation time necessary for tissue a-tocopherol levels to respond to dietary a-tocopherol has not been established. This study had two objectives: (1) to investigate the effect of duration of pre-slaughter supplementation of pig diets with a-tocopheryl acetate on a-tocopherol levels in porcine tissues including muscle; and (2) to determine the effect of dietary a-tocopheryl acetate on lipid oxidation in pork.