Effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef

Abstract

The objective of the study was to examine the effect of vitamin E on α-tocopherol concentration in different tissues and oxidative stability of bull beef. In a 2 (length of vitamin E supplementation; 80 or 120 days)×3 (level of vitamin E supplementation; control, 600 or 2000 mg/animal/day) factorial experiment, 66 German Fleckvieh bulls (starting weight at 568±23 and 530±20 kg, respectively, for the two groups on the length of supplementation) were given 2.6 kg concentrate per day together with maize silage ad libitum up to the same mean slaughter weight of 641±29 kg. At slaughter, the intramuscular fat contents of the M. longissimus thoracis (MLT) and the M. semitendinosus (MST) were low, with mean values of 1.60 and 1.14%, respectively. The α-tocopherol concentrations in the serum, liver, kidney fat and muscle tissues increased with level and duration of supplementation. However, MLT and MST reached only mean α-tocopherol contents of 1.11 (600 mg–80 days) to 2.79 mg/kg (2000 mg–120 days), and 1.48 (600 mg–80 days) to 3.56 mg/kg (2000 mg–120 days) in vitamin E-supplemented animals in comparison with 0.56 and 0.65 mg/kg in controls, respectively. The level of vitamin E supplementation had a much clearer effect on the α-tocopherol concentrations in the tissues than did the duration of supplementation. The intensity of redness of the muscle tissue remained relatively constant in the supplemented groups up to a storage time of 7–9 days, arrived after 10 days of ageing time, whilst significant darkening of the meat was observed in the controls after 4 days. Vitamin E supplementation also resulted in a delay in the increase of metmyoglobin in the pigment fraction, in a reduction of fat oxidation and in a tendency for reduced drip loss. Duration of vitamin E supplementation tended to have a clearer effect than level of supplementation on meat colour and oxidative stability of bull beef.