Effect of dietary alpha-tocopheryl acetate on the uptake and distribution of alpha-tocopherol in turkey tissues and lipid stability

The effect of including all-rac-alpha-tocopheryl acetate [20 (E20), 300 (E300) and 600 (E600) mg/kg diet] in the diet of turkeys, for up to 21 weeks, on uptake and distribution of alpha-tocopherol and on the oxidative stability of tissues was investigated. Marked differences were observed in the concentrations of alpha-tocopherol in different tissues. Overall alpha-tocopherol levels responded to dietary intake in the order of gizzard > heart > lung approximate to spleen > liver > thigh muscle > abdominal fat > breast muscle > brain. After 5 weeks of supplementation with 300 mg alpha-tocopheryl acetate/kg, the alpha-tocopherol levels of both thigh [2.8 (s.d. 0.22) mu g/g] and breast muscle [1.6 (s.d. 0.18) mu g/g] were similar to 3- to 6-fold higher than the basal levels in thigh and breast, In the case of breast muscle, only a small but insignificant increase in the alpha-tocopherol concentration was observed with further supplementation for up to 21 weeks. However, the levels of alpha-tocopherol in thigh muscle further increased significantly (P < 0.01) after 9 [3.7 (s.d. 0.18) mu g/g] and 13 [4.5 (s.d. 0.28) mu g/g] weeks of supplementation. The levels of alpha-tocopherol were significantly (P < 0.01) higher at all time points (except week 1) in both muscles from turkeys fed the E600 diet compared with those fed the E300 diet, In the E600 group, the alpha-tocopherol levels increased at an average weekly rate of 0.30 mu g/g and 0.23 mu g/g up to week 13 for thigh and breast, respectively. The stability of heart, breast and thigh muscle against iron/ascorbate-induced lipid peroxidation was significantly increased by alpha-tocopherol supplementation (300 or 600 mg/kg) for 21 weeks.