中型褐壳产蛋鸡饲粮钙适宜水平的研究

Studies on the Optimum Level of Dietary Calcium for Heavy-Typed Brown Eggshell Layers

用 2 0周龄的商品代北京红鸡 1 5 0只 ,按完全随机设计以体重随机分为 5个处理组 ,分别喂以含钙水平为 2 .5 %、3.0 %、3.5 %、4.0 %和 4.5 %及非植酸磷水平均为 0 .2 5 %的玉米 豆粕型饲粮 2 0周 ,研究中型褐壳产蛋鸡在 2 0～ 40周龄产蛋阶段的饲粮钙适宜水平。饲粮钙水平对产蛋率、蛋重、产蛋量、耗料量、饲料效率、蛋形指数、哈夫单位、蛋壳百分率和血浆钙含量无明显影响 (P >0 .1 0 ) ,而显著影响了蛋壳厚度、蛋壳强度、蛋壳重、骨灰及蛋壳钙含量 (P <0 .0 5 )。随着饲粮钙水平的增加 ,蛋壳厚度、蛋壳强度和蛋壳重均呈曲线型增加 ,当饲粮钙水平升至 4.0 %时均增至最大。本次研究结果表明 ,蛋壳厚度、蛋壳强度和蛋壳重是评价中型褐壳产蛋鸡饲粮钙营养需要量的敏感指标 ;北京红中型褐壳产蛋鸡在 2 0～ 40周龄产蛋阶段的玉米 -豆粕型饲粮中钙水平以 4.0 %(实测值为 3.94%,每日钙进食量为 4.1 8g)为宜 ,比美国现行NRC( 1 994)对中型褐壳产蛋鸡饲粮钙建议需要量 ( 3.2 7%钙 ,每日钙进食量为 3.60g)

An experiment was conducted using a total of 150 20 week old commercial Beijing Red layers to study the optimum level of dietary Ca for those layers during a phase of 20～40 weeks.Layers were randomly allotted to five treatments according to bodyweight in a completely randomized design,and fed the corn soybean meal diets containing 2.5,3.0,3.5,4.0 or 4.5% Ca at 0.25% nonphytate phosphorus,respectively for 20 weeks.Dietary Ca level had no effect (P>0.10) on egg production rate ,egg weight,egg yield,feed intake,feed conversion efficiency,egg shape index,Haugh unit ,percentage of eggshell,and plasma Ca,but influenced(P<0.05)eggshell thickness,eggshell strength,eggshell weight,and Ca contents in bone ash and eggshell.With increasing dietary Ca levels,eggshell thickness,eggshell strength,and eggshell weight increased in a curvilinear manner,with the greatest values at 4.0% Ca level.The results from this study indicate that eggshell thickness,eggshell strength,and eggshell weight were sensitive indices for evaluating dietary Ca requirement of brown eggshell layers;And 4.0% Ca(the analyzed value: 3.97%, and daily Ca intake:4.18 g)in a basal corn soybean diet was an optimum level for 20～40 week old commercial Beijing Red layers,Which is higher than that(3.27% Ca,and daily Ca intake:3.60 g)recommended for brown eggshell layers by NRC(1994).