日粮硒水平对熟化过程中牛肉氧化稳定性和抗氧化酶活力的影响

Influence of Dietary Selenium Level on the Oxidative Stability of Beef and the Activity of Antioxidative Enzymes During the Maturation

研究了熟化过程中抗氧化酶谷胱甘肽过氧化物酶 (GPx)和超氧化物岐化酶 (SOD)活力的动态变化 ,及日粮硒水平对牛肉氧化稳定性和抗氧化酶活力的影响。选择 12头体重 4 2 0～ 5 6 0kg的健康晋南牛阉牛 ,按体重分为 3组 ,每组 4头 ,试验期为 2个月。采用单因子试验设计 ,硒的添加水平为 0、0 .10和 0 .4 0mg·kg-1。结果表明 ,0 .10mg·kg-1组的全血和臀中肌硒含量高于 0mg·kg-1组 (P >0 .0 5 ) ,0 .4 0mg·kg-1组的组织硒含量显著高于前 2个处理组 (P <0 .0 1) ;与 0和 0 .10mg·kg-1组相比 ,日粮中添加 0 .4 0mg·kg-1硒可显著提高全血GPx和熟化过程中臀中肌GPx酶活力 (P <0 .0 1) ,但对组织SOD酶活力影响差异不显著 (P >0 .0 5 ) ;从熟化的第 3天到第 14天 ,各组牛肉GPx酶活力变化不显著 (P >0 .0 5 ) ,但SOD酶活变化较大 ,熟化第 9天的酶活力显著低于熟化第 3天的酶活力 (P <0 .0 5 ) ;虽然提高日粮硒水平可显著增强熟化过程中牛肉GPx酶活力 ,但GPx酶活力的增强没有明显降低牛肉TBARS值 (表示脂质氧化 )、滴水损失和METMB(高铁肌红蛋白 )含量。

The dynamic changes of antioxidative enzymes's activities during the maturation and the influence of dietary selenium level on the activities of antioxidative enzymes and the oxidative stability of beef were studied. Twelve 420-560 kg Jinnan steers were selected and divided into three groups by virtue of liveweight. Steers were allocatted into a 1×3 factorial experiment with three levels of selenium (0, 0.10 and 0.40 mg·kg -1 ). The results were demonstrated that α tocopherol concentrations in plasma and GM (gluteus medius) were not elevated ( P> 0.05) by selenium supplementation. Selenium concentrations in tissues from the group fed the diet with 0.40 mg·kg -1 selenium were higher (P<0.01) than those from the groups fed the diet with 0 or 0.10 mg·kg -1 Se, and selenium contents from the treatment of 0.10 mg·kg -1 Se were higher than those from the treatment of 0 mg·kg -1 Se, but the difference was not significant(P>0.05). The addition of 0.40 mg·kg -1 Se into the diet apparently increased GPx (glutathione peroxidase) activities in blood and GM (P< 0.01 ), but SOD (superoxide dismutase) activities were not affected(P>0.05) by dietary treatments. The levels of GPx activities remained constant from 3rd day to 14th day during the maturation, but SOD activities decreased as maturation time elongated, the enzyme activities on 9th day were lower than those on 3rd day (P< 0.05 ). Although the levels of GPx activities rose with increasing dietary selenium, the increased activities did not hinder lipid oxidation(P>0.05). No statistically significant difference in TBARS value, color stability and drip loss between the different dietary treatments was found(P>0.05). It was concluded that dietary selenium level had no significant influence on the oxidative stability of beef during the maturation.