本试验旨在研究硒和维生素E对肉牛养分表观消化率、氮平衡、能量代谢及血液生化指标的影响。选用4头5岁、平均体重(500±20) kg的装有永久性瘤胃瘘管的西门塔尔阉牛,采用4×4双因素随机设计,在饲粮中分别添加0、0.1、0.2和0.3 mg/kg硒和0、30、60和90 IU/kg的维生素E,共形成16组饲粮,硒水平(mg/kg)/维生素E水平(IU/kg)分别为0/0(1组)、0.1/0(2组)、0.2/0(3组)、0.3/0(4组)、0/30(5组)、0.1/30(6组)、0.2/30(7组)、0.3/30(8组)、0/60(9组)、0.1/60(10组)、0.2/60(11组)、0.3/60(12组)、0/90(13组)、0.1/90(14组)、0.2/90(15组)、0.3/90(16组)。检测肉牛养分表观消化率、氮平衡、能量代谢和血液生化指标的变化。结果表明:1)14组饲粮有机物表观消化率显著高于1组(P<0.05),8组粗蛋白质和干物质表观消化率显著高于1组(P<0.05),11和12组粗脂肪表观消化率显著或极显著高于1、2和3组(P<0.05或P<0.01),8、12和14组的无氮浸出物表观消化率显著高于1组(P<0.05),各组中性洗涤纤维表观消化率差异不显著(P>0.05),4、7、8、12和14组的酸性洗涤纤维表观消化率显著高于1组(P<0.05)。2)8组的可消化氮显著高于1组(P<0.05),4、8和14组的沉积氮显著高于1、2、5和9组(P<0.05)。3)添加硒和维生素E对粪能、气体能和沉积能无显著影响(P>0.05),4和8组的消化能和代谢能显著高于2组(P<0.05)。4)添加硒和维生素E对血清葡萄糖、总蛋白、尿素氮含量影响不显著(P>0.05),4、8和12组的白蛋白含量和谷胱甘肽过氧化物酶活性显著高于1组(P<0.05),谷丙转氨酶活性显著或极显著高于其余组(P<0.05或P<0.01),8、12、13和14组的谷草转氨酶活性显著高于其余组(P<0.05),1、9和13组的甲状腺素含量显著高于其余组(P<0.05),12组的三碘甲腺原氨酸含量显著高于除4、8和15组外的其余组(P<0.05)。综上所述,添加硒和维生素E提高了饲粮养分表观消化率,促进了氮平衡和能量代谢,硒和维生素E的适宜添加水平分别是0.3 mg/kg、30 IU/kg。

This study was conducted to investigate the effects of selenium and vitamin E on nutrient apparent digestibility, nitrogen balance, energy metabolism and blood biochemical indices of beef cattle. Four Simmental steers [average body weight was (500±20) kg, 5 years of age] with permanent rumen fistulas were used in a 4×4 two-factor design, and fed the diets supplemented with 0, 0.1, 0.2 and 0.3 mg/kg selenium and 0, 30, 60 and 90 IU/kg vitamin E, respectively. There were 16 diets in all. Selenium (mg/kg)/vitamin E (IU/kg) levels were 0/0 (group 1), 0.1/0 (group 2), 0.2/0 (group 3), 0.3/0 (group 4), 0/30 (group 5), 0.1/30 (group 6), 0.2/30 (group 7), 0.3/30 (group 8), 0/60 (group 9), 0.1/60 (group 10), 0.2/60 (group 11), 0.3/60 (group 12), 0/90 (group 13), 0.1/90 (group 14), 0.2/90 (group 15) and 0.3/90 (group 16), respectively. Changes of nutrient apparent digestibility, nitrogen balance, energy metabolism and blood biochemical indices of beef cattle were analyzed. The results showed as follows: 1) the digestibility of OM in group 14 was significantly higher than that in group 1(P<0.05), the digestibility of CP and DM in group 8 was significantly higher than that in group1 (P<0.05), EE digestibility in groups 11 and 12 was significantly higher than that in groups 1, 2 and 3 (P<0.05), NFE digestibility in groups 8, 12 and 14 was significantly higher than that in group 1 (P<0.05), NDF digestibility was not affected (P>0.05), and ADF digestibility in groups 4, 7, 8, 12 and 14 was significantly higher than that in group 1 (P<0.05). 2) Digestive nitrogen in group 8 was significantly higher than that in group 1 (P<0.05), and retention nitrogen in groups 4, 8 and 12 was significantly higher than that in groups 1, 2, 5 and 9 (P<0.05). 3) Fecal energy, gaseous energy and energy retention were not significantly affected (P>0.05), but digestible energy and metabolizable energy in groups 4 and 8 were significantly higher than those in group 1 (P<0.05). 4) Serum glucose, total protein and urea nitrogen contents were not significantly affected (P>0.05), but albumin content and GSH-Px activity in groups 4, 8 and 12 were significantly higher than those in group 1 (P<0.05), and GPT activity was significantly higher than that in the other groups (P<0.05 or P<0.01), GOT activity in groups 8, 12, 13 and 14 was significantly higher than that in the other groups (P<0.05), T₄ content in groups 1, 9 and 13 was significantly higher than that in the other groups (P<0.05), and T₃ content in group 12 was higher than that in the other groups except for groups 4, 8 and 15 (P<0.05). The results indicate that selenium and vitamin E have a positive influence on nutrient apparent digestibility, nitrogen balance and energy metabolism. The optimum selenium and vitamin E supplemental levels are 0.3 mg /kg and 30 IU/kg, respectively.