【摘要】 用 2 0周龄的商品代北京红鸡 12 0只进行试验 ,研究中型褐壳产蛋鸡在 2 0～ 43周龄阶段实用饲粮中Mn的适宜水平。试鸡按完全随机设计以体重随机分为 5个处理组 ,分别饲喂未添加Mn的玉米 豆粕型基础饲粮 (含Mn19mg/kg)和在这一基础饲粮中分别添加 30、6 0、90和 12 0mg/kgMn(试剂级MnSO4 ·H2 O)的饲粮。鸡只自由采食与饮水。饲粮Mn水平对产蛋率、蛋重、产蛋量、采食量、料蛋比、蛋形指数、哈夫单位、蛋壳百分率、蛋壳厚度、破蛋率、血清新城疫 (NDV)抗体滴度、多数血浆生化指标和肝细胞线粒体中含Mn超氧化物歧化酶 (MnSOD)活性无显著影响 (P >0 10 ) ,但对蛋壳强度 (P <0 0 0 1)、心肌、胰及脾中Mn含量 (P <0 10 )和心肌细胞线粒体中MnSOD活性 (P <0 0 0 1)有显著影响。随饲粮Mn水平的增加 ,蛋壳强度、心肌、胰、脾中Mn含量和心肌细胞线粒体中Mn SOD活性呈渐近线型或二次抛物线型增加。蛋壳强度、心肌Mn含量和心肌细胞线粒体MnSOD活性分别与饲粮Mn水平很好地拟合断线模型 (P <0 0 5 )、二次曲线模型 (P <0 0 3)和渐近线型模型 (P <0 0 0 1)。以上述最优拟合数学模型计算获得理想蛋壳强度、心肌Mn含量和心肌细胞线粒体MnSOD活性所需的饲粮Mn水平分别为 45、10 0和 10 5mg/kg。结果表明 ,心肌Mn含?更多还原

【Abstract】 An experiment was conducted using a total of 120 20-week old Beijing Red commercial layers to study the optimal Mn level in a practical diet for brown-egg layers during a phase of 20～43 weeks.Layers were randomly allocated by body weight to one of five treatments according to the completely randomized design,and fed a Mn-unsupplemented corn-soybean meal basal diet containing 19 mg/kg Mn and the basal diets supplemented with 30,60,90 or 120 mg/kg Mn as reagent grade MnSO 4·H 2O,respectively.Layers were allowed ad libitum access to feed and tap water.Dietary Mn level had no effect(P>0.10)on egg production rate,egg weight,egg yield,daily feed intake,feed/egg ratio,egg shape index,haugh unit,eggshell percentage,eggshell thickness,broken egg percentage,serum antibody titer against Newcastle Disease Vaccine(NDV),most plasma biochemical parameters,and Mn-containing superoxide dismutase(MnSOD)activity in liver,but affected eggshell strength(P<0.01),Mn contents in heart,pancreas and spleen(P<0.10),and heart MnSOD activity(P<0.001).As dietary Mn levels increased,eggshell strength,Mn contents in heart,pancreas and spleen,and heart MnSOD activity increased in an asymptote or in a quadratic curve.Broken-line model(P<0.05)of eggshell strength,quadratic curve model(P<0.03)of heart Mn content,and asymptote model(P<0.001)of heart MnSOD activity could be well fitted with dietary Mn levels,respectively.Dietary Mn levels required to obtain satisfactory eggshell strength,heart Mn content,and heart MnSOD activity based on the above best fitted models were 45,100,and 105 mg/kg,respectively.The results from this study indicate that heart Mn content and heart MnSOD activity,especially heart MnSOD activity,are the specially sensitive indices to evaluate Mn requirements of layers;And the 105 mg/kg Mn in the basal corn-soybean meal diet should be a satisfactory level for 20～43 week-old brown-egg layers at the average daily feed intake of 113 g,which is 5.25 times of the amount(20 mg/kg)recommended by NRC(1994)in Nutrient Requirements of Poultry.更多还原