Kasapidou E, Enser M, Wood J D, Richardson R I, Wilkinson R G, Sinclair L A
1Division of Farm Animal Science, University of Bristol, Langford, Bristol BS40 5DU, UK.
Animal. 2009 Apr;3(4):516-26. doi: 10.1017/S1751731108003820.
In order to determine the effect of dietary vitamin E level and basal diet on vitamin E status, performance and tissue fatty acid content, five groups of eight Suffolk × Charollais wether lambs with an initial live weight of 28.4 (s.d. 1.6) kg were allocated to one of five concentrate-based diets supplemented with all-rac-α-tocopheryl acetate to contain 30 mg (C-30), 60 mg (C-60), 120 mg (C-120), 250 mg (C-250) or 500 mg (C-500) α-tocopheryl acetate/kg dry matter (DM), for 63 days. Two additional groups of eight lambs entered the study at 31.2 (s.d. 3.3) kg and were fed grass silage and 400 g/day concentrate for 56 days, with the whole diet providing the equivalent of 60 mg (S-60) or 500 mg (S-500) α-tocopheryl acetate/kg DM. Lambs were weighed and blood samples obtained by venipuncture weekly. Dietary vitamin E level did not affect performance (P > 0.05), but lambs fed grass silage grew more slowly (P < 0.001) and had a higher (P < 0.001) feed conversion ratio (kg feed/kg gain) than those fed concentrates. At day 0 plasma α-tocopherol concentrations were 0.8 μg/ml and did not differ between treatments (P > 0.05). Plasma α-tocopherol concentrations then decreased in all lambs except for those fed S-500, which increased, and at slaughter were (μg/ml) 0.07, 0.23, 0.39, 0.76 and 1.57 in C-30, C-60, C-120, C-250 and C-500 and 1.18 and 1.93 in S-60 and S-500, respectively. At slaughter, muscle and liver α-tocopherol concentrations were in the deficiency range for lambs fed C-30, C-60 or C-120, whereas plasma creatine kinase and tissue polyunsaturated fatty acids were unaffected by dietary vitamin E level, but creatine kinase levels were higher (P < 0.05) and glutathione peroxidise levels lower (P < 0.001) in lambs fed grass silage than concentrates alone. Muscle and liver α-tocopherol concentrations were 1.8- and 4.1-fold higher in lambs fed S-60 than C-60, but there was less of a difference between lambs fed S-500 or C-500 with muscle and liver differences of 0.4- and 0.7-fold, respectively. Tissue n-3 polyunsaturated fatty acid concentrations were higher (P < 0.05) and n-6 fatty acids lower in lambs receiving the grass silage compared to concentrate-based diets, but were not affected by dietary vitamin E level. It is concluded that lower plasma and tissue levels of α-tocopherol are present in lambs supplemented with all-rac-α-tocopheryl acetate on a concentrate compared to a mixed diet of silage and concentrates, and that normal growth can be achieved at tissue levels previously considered to represent deficiency.
为了确定日粮维生素E水平和基础日粮对维生素E状态、生产性能及组织脂肪酸含量的影响，将五组初始体重为28.4（标准差1.6）kg的萨福克×夏洛莱阉公羊，每组8只，分配到五种以精料为主的日粮中，这些日粮添加了消旋-α-生育酚醋酸酯，使其每千克干物质（DM）中含有30毫克（C-30）、60毫克（C-60）、120毫克（C-120）、250毫克（C-250）或500毫克（C-500）α-生育酚醋酸酯，为期63天。另外两组，每组8只公羊，初始体重为31.2（标准差3.3）kg，进入本研究，饲喂青贮草和每天400克精料，为期56天，整个日粮每千克DM提供相当于60毫克（S-60）或500毫克（S-500）α-生育酚醋酸酯。每周对公羊称重并通过静脉穿刺采集血样。日粮维生素E水平不影响生产性能（P>0.05），但与饲喂精料的公羊相比，饲喂青贮草的公羊生长较慢（P<0.001）且饲料转化率较高（P<0.001）（千克饲料/千克增重）。在第0天，血浆α-生育酚浓度为0.8微克/毫升，各处理间无差异（P>0.05）。除饲喂S-500的公羊血浆α-生育酚浓度升高外，所有公羊的血浆α-生育酚浓度随后均下降，屠宰时，C-30、C-60、C-120,、C-250和C-500组公羊的血浆α-生育酚浓度分别为0.07、0.23、0.39、0.76和1.57微克/毫升，S-60和S-500组分别为1.18和1.93微克/毫升。屠宰时，饲喂C-30、C-60或C-120的公羊肌肉和肝脏α-生育酚浓度处于缺乏范围，而血浆肌酸激酶和组织多不饱和脂肪酸不受日粮维生素E水平影响，但与仅饲喂精料的公羊相比，饲喂青贮草的公羊肌酸激酶水平较高（P<0.05），谷胱甘肽过氧化物酶水平较低（P<0.001）。饲喂S-60的公羊肌肉和肝脏α-生育酚浓度分别比饲喂C-60的公羊高1.8倍和4.1倍，但饲喂S-500或C-500的公羊之间差异较小，肌肉和肝脏差异分别为0.4倍和0.7倍。与以精料为主的日粮相比，饲喂青贮草的公羊组织n-3多不饱和脂肪酸浓度较高（P<0.05），n-6脂肪酸浓度较低，但不受日粮维生素E水平影响。得出结论，与青贮料和精料的混合日粮相比，以精料为主并添加消旋-α-生育酚醋酸酯的公羊血浆和组织中α-生育酚水平较低，并且在以前认为代表缺乏的组织水平下也可实现正常生长。
