东北玉米肉鸡表观代谢能预测方程的建立

本研究旨在通过实验室分析和肉鸡代谢试验建立东北玉米养分含量与代谢能的回归方程,为生产提供便捷的玉米代谢能估算方法。试验1:选取成熟季节不同的20种东北玉米,测定养分含量和容重,分析养分含量变异范围。试验2:用玉米、玉米皮、玉米碴按照中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)含量梯度配制人工玉米,再添加一定量的维生素和矿物质,配制成人工玉米代谢饲粮。选取正常饲养的商品代爱拔益加雄性肉鸡进行代谢试验,分别在11~13日龄及25~27日龄,用全收粪法测定人工玉米代谢饲粮表观代谢能(AME)、氮校正表观代谢能(AMEn)和养分表观消化率,并采用逐步回归法建立AME及AMEn与养分含量的回归方程。结果表明:东北玉米粗脂肪(EE)、NDF及ADF含量变异系数相对较大,分别为16.72%、14.65%、14.72%。肉鸡对人工玉米代谢饲粮的养分表观消化率在11~13日龄和25~27日龄之间存在差异,25~27日龄肉鸡对人工玉米代谢饲粮粗蛋白质(CP)、EE和总淀粉(STC)的表观消化率高于11~13日龄,其中EE表观消化率差异显著(P0.05);25~27日龄肉鸡对人工玉米代谢饲粮的AME、AMEn也显著高于11~13日龄(P0.05)。采用逐步回归法建立肉鸡东北玉米代谢能的预测方程为:11~13日龄,AME=17.661-0.853ADF(R2=0.870,P0.01),AM En=17.468-0.878ADF(R2=0.873,P0.01);25~27日龄,AM E=18.102-0.792ADF(R2=0.781,P0.05),AM En=17.935-0.830ADF(R2=0.784,P0.05)。通过预测方程计算所得人工玉米代谢饲粮AME的预测值与实测值很接近,计算所得的东北玉米AME符合预期值。由此得出,不同品种东北玉米EE、NDF及ADF的含量差异相对较大;肉鸡不同阶段玉米代谢能存在差异,计算肉鸡饲粮配方时,不同阶段饲粮代谢能应采用对应的代谢能值;低于14日龄的肉鸡,东北玉米AM E、AM En预测方程分别为AM E=17.661-0.853ADF,AM En=17.468-0.878ADF;14日龄以上的肉鸡,东北玉米AME、AMEn预测方程分别为AME=18.102-0.792ADF,AMEn=17.935-0.830ADF。     

不同比例豆粕组合的营养价值及肉仔鸡代谢能预测模型的建立

本试验通过不同比例豆粕和豆皮配制出不同种类的6种人工豆粕,测定人工豆粕营养成分含量和代谢能,旨在建立豆粕的肉仔鸡代谢能预测模型。选取1 008只1日龄爱拔益加(AA)公雏鸡,随机分为7组(其中1组为饥饿组),每组8个重复,每个重复18只鸡。于14～16日龄采用全收粪法测定肉仔鸡的表观代谢能(AME)、氮校正表观代谢能(AMEn)、真代谢能(TME)和氮校正真代谢能(TMEn),并采用营养成分逐步回归建立肉仔鸡代谢能预测方程。结果表明:1)配制的6种人工豆粕中粗蛋白质(CP)含量呈梯度增加,粗脂肪(EE)、粗纤维(CF)、中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量变异系数较大,分别为24.65%、42.57%、33.86%和45.09%。2)碳水化合物成分中蔗糖、棉子糖和水苏糖含量平均值分别为49.86、12.88和42.79 g/kg。3)14～16日龄肉仔鸡不同人工豆粕饲粮AME、AMEn、TME和TMEn平均值分别为11.68、11.48、12.30和12.06 MJ/kg,不同人工豆粕原料AME、AMEn、TME和TMEn平均值分别为11.36、11.17、12.74和12.51 MJ/kg。4)用常规营养成分含量逐步回归建立肉仔鸡代谢能预测方程如下:AME=9.078-0.123CF+0.060CP(R2=0.982, P 0.01), AME=2.236+0.187CP-0.120EE(R2=0.911,P 0.01);用寡糖含量建立肉仔鸡预测方程为AME=4.825+0.121CP+0.019蔗糖-0.229EE(R2=0.970,P0.01)等。用交叉验证法验证常规营养成分的预测方程,预测值和实测值接近,建立的肉仔鸡代谢能预测模型较成功。     

肉仔鸡饲料原料代谢能的生物学评定及可加性研究

本试验选用22日龄爱拔益加商品代肉仔鸡336只(公母各半),随机分为7个处理,每个处理8个重复(公母各4个重复),每个重复6只鸡.分别饲喂玉米、豆粕、棉粕、菜粕、玉米-豆粕、玉米-棉粕、玉米-菜粕7种试验日粮,测定28日龄肉仔鸡的表现代谢能(AME)和氮校正表观代谢能(AMEn).玉米、豆柏、棉粕、菜粕的AME分别为14.82、12.10、11.17、9.79 MJ/kg,AMEn分别为14.80、11.81、10.81、9.60 MJ/kg.三种混合日粮AME匝和AMEn的预测值与测定值差异不显著(P＞0.05),表明玉米和豆粕、棉粕、菜粕的AME和AMEn存在可加性.     

肉仔鸡对菜籽粕代谢能的评定及预测模型研究

旨在建立14及28日龄肉仔鸡对湖南省内6个不同地区菜籽粕表观代谢能（AME）和氮校正表观代谢能（AMEn）的预测方程。本试验共选取700羽1日龄AA肉仔鸡,根据日龄进行两个阶段的试验。第一阶段（7~14日龄）选取420羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复6羽;第二阶段（21~28日龄）选取280羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复4羽。两个阶段中的7个处理组分别为6个不同地区的菜籽粕采用全替代法设计的试验饲粮组和1个无氮饲粮组。采用全收粪法测定14及28日龄肉仔鸡对菜籽粕的AME和AMEn,并通过回归分析建立预测方程。结果表明,14日龄肉仔鸡对菜籽粕的AME和AMEn分别为7.44和7.35 MJ·kg^-1,AME和AMEn最佳预测方程分别为AME=24.98-0.39NDF和AMEn=25.04-0.39NDF;28日龄肉仔鸡对菜籽粕的AME和AMEn分别为8.01和7.91 MJ·kg^-1,AME和AMEn最佳预测方程分别为AME=23.08-0.34NDF和AMEn=23.06-0.34NDF。本研究结果完善了肉仔鸡菜籽粕代谢能的数据库,为菜籽粕在畜禽饲粮中的应用提供了支撑。     

肉仔鸡对菜籽粕代谢能的评定及预测模型研究

旨在建立14及28日龄肉仔鸡对湖南省内6个不同地区菜籽粕表观代谢能(AME)和氮校正表观代谢能(AMEn)的预测方程。本试验共选取700羽1日龄AA肉仔鸡,根据日龄进行两个阶段的试验。第一阶段(7～14日龄)选取420羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复6羽;第二阶段(21～28日龄)选取280羽肉仔鸡随机分为7个处理,每个处理10个重复,每个重复4羽。两个阶段中的7个处理组分别为6个不同地区的菜籽粕采用全替代法设计的试验饲粮组和1个无氮饲粮组。采用全收粪法测定14及28日龄肉仔鸡对菜籽粕的AME和AMEn,并通过回归分析建立预测方程。结果表明,14日龄肉仔鸡对菜籽粕的AME和AMEn分别为7.44和7.35 MJ·kg~(-1),AME和AMEn最佳预测方程分别为AME=24.98-0.39NDF和AMEn=25.04-0.39NDF;28日龄肉仔鸡对菜籽粕的AME和AMEn分别为8.01和7.91 MJ·kg~(-1),AME和AMEn最佳预测方程分别为AME=23.08-0.34NDF和AMEn=23.06-0.34NDF。本研究结果完善了肉仔鸡菜籽粕代谢能的数据库,为菜籽粕在畜禽饲粮中的应用提供了支撑。     

黄羽肉鸡饲料原料代谢能的测定

试验选用35日龄快大型黄羽肉鸡96只,随机分为4组,每组6个重复,每个重复4只鸡,分别饲喂以玉米淀粉、大麦、鱼粉和花生粕为基础原料配制的4种日粮。采用指示剂法测定玉米淀粉、大麦、鱼粉和花生粕的总能消化率、表观代谢能(AME)和氮校正表观代谢能(AMEn)。结果表明:黄羽肉鸡玉米淀粉、大麦、鱼粉和花生粕的总能消化率分别为68.77%、65.67%、89.57%、75.85%,AME分别为8.82、9.45、13.27、11.22 MJ/kg,AMEn分别为8.71、9.34、13.00、10.99 MJ/kg。     

玉米蛋白粉肉仔鸡代谢能预测方程的建立

本试验旨在测定6种我国不同来源的玉米蛋白粉养分含量及其肉仔鸡生物学效价,以建立玉米蛋白粉的肉仔鸡代谢能预测模型。测定6种玉米蛋白粉的常规养分含量、醇溶蛋白(zein)含量、容重和色度,分析其变异情况。采用套算法添加10%玉米蛋白粉配制试验饲粮,选取1日龄爱拔益加(AA)肉仔鸡,分别于11～13日龄及25～27日龄采用全收粪法测定肉仔鸡的表观代谢能(AME)、氮校正表观代谢能(AMEn)、真代谢能(TME)、氮校正真代谢能(TMEn),并采用逐步回归法建立肉仔鸡代谢能与玉米蛋白粉特性的回归方程。结果表明:1)不同来源玉米蛋白粉的粗脂肪(EE)、粗灰分(Ash)及中性洗涤纤维(NDF)含量变异相对较大,变异系数分别为46.49%、33.17%、30.62%;粗蛋白质(CP)、总能(GE)及干物质(DM)含量变异相对较小,变异系数分别为6.71%、2.13%、1.20%。2) 11～13日龄时肉仔鸡的AME、AMEn、TME、TMEn均值分别为11. 55、11. 13、10. 04、11. 04 MJ/kg;25～27日龄时肉仔鸡的AME、AMEn、TME、TMEn均值分别为12.29、11.74、11.79、15.35 MJ/kg。3)以逐步回归模型建立玉米蛋白粉的肉仔鸡代谢能预测方程为:11～13日龄时AME=-0.007CP+0.013b~*+0.061Ash+11.441(R~2=0.959,P=0. 024), AMEn=-0. 017CP+12. 245 (R~2=0. 681, P=0. 027), TME=-0. 011CP+0.011b~*+10.351(R~2=0.877,P=0.020),TMEn=-0.101CP+0.101b~*+13.898(R~2=0.819,P=0.036);25～27日龄时TME=0.014NDF+11.618(R~2=0.646,P0.05)。用该方程计算所得玉米蛋白粉肉仔鸡代谢能的预测值与实测值很接近,表明玉米蛋白粉的肉仔鸡代谢能预测模型建立成功。     

河南省小麦肉鸡代谢能预测方程的建立

本试验采用化学分析和肉鸡代谢试验建立了河南省小麦养分含量与代谢能的回归方程。试验1:选取河南省11种不同的成熟小麦,测定概略养分含量和容重,分析养分含量变化范围。试验2:用小麦、次粉、麸皮、面粉按照总戊聚糖含量梯度配制人工小麦,再添加一定量的维生素和矿物质,配制成人工小麦代谢饲粮。选取常规饲养的商品代罗斯308雄性白羽肉鸡进行代谢试验,分别在11~13日龄和25~27日龄,用全收粪法测定人工小麦代谢饲粮的表观代谢能(AME)、真代谢能(TME)、氮校正表观代谢能(AMEn)和氮校正真代谢能(TMEn),并采用逐步回归法建立AME、TME、AMEn和TMEn的回归方程。结果表明:1)河南省小麦粗脂肪(EE)、中性洗涤纤维(NDF)、酸性洗涤纤维(ADF)及总磷(TP)含量的变异系数相对较大,分别为16.67%、15.84%、14.96%、19.32%。2)肉鸡对人工小麦代谢饲粮的养分表观代谢率在11~13日龄和25~27日龄存在差异,25~27日龄肉鸡对人工小麦代谢饲粮ADF、粗纤维(CF)的表观代谢率高于11~13日龄,AME、TME、AMEn和TMEn也高于11~13日龄。3)采用逐步回归法建立河南省小麦肉鸡代谢能的预测方程为:11~13日龄,AME=14.628-0.184NDF(R2=0.842,P<0.01),TME=15.49-0.197NDF(R2=0.854,P<0.01),AMEn=14.571-0.184NDF(R2=0.847,P<0.01),TMEn=15.49-0.197NDF(R2=0.854,P<0.01);25~27日龄,AME=15.462-0.217NDF(R2=0.797,P<0.01),TME=16.124-0.214NDF(R2=0.809,P<0.01),AMEn=15.179-0.208NDF(R2=0.801,P<0.01),TMEn=16.123-0.214NDF(R2=0.809,P<0.01)。4)通过预测方程计算所得人工小麦代谢饲粮AME、TME、AMEn和TMEn的预测值与实测值很接近,计算所得的河南省小麦AME、TME、AMEn和TMEn符合预期值。由此得出,不同品种河南省小麦之间EE、NDF、ADF及TP的含量差异相对较大;不同日龄阶段的肉鸡对小麦代谢能存在差异,设计肉鸡饲粮配方时,不同阶段饲粮代谢能应采用对应的代谢能值;低于14日龄的肉鸡,预测方程为AME=14.628-0.184NDF,TME=15.49-0.197NDF,AMEn=14.571-0.184NDF,TMEn=15.49-0.197NDF;14日龄以上的肉鸡,预测方程为AME=15.462-0.217NDF,TME=16.124-0.214NDF,AMEn=15.179-0.208NDF,TMEn=16.123-0.214NDF。     

90～100日龄慢速型黄羽肉鸡常规能量和糠麸类饲料原料代谢能评定

试验旨在为慢速型黄羽肉鸡日粮配制提供数据参考并完善我国黄羽肉鸡饲料原料基础数据库,选用90日龄清远麻鸡168只,按体重随机均分成7组,每组6个重复,每个重复4只鸡。试验预饲3 d,全收粪3 d。7组分别饲喂基础日粮、30%玉米日粮、30%大麦日粮、30%小麦日粮、30%高粱日粮、25%麦麸日粮、30%米糠日粮。采用全收粪和套算法测定总能(GE)代谢率、表观代谢能(AME)和氮校正代谢能(AMEn)。结果表明:玉米、大麦、小麦、高粱、麦麸和米糠的总能代谢率分别为83.0%、82.5%、83.3%、83.9%、39.5%、65.9%,AME分别为13.56、12.98、13.10、13.61、6.99、11.92 MJ/kg,AMEn分别为13.41、12.61、12.93、13.41、6.54、11.52 MJ/kg。     

不同来源玉米对大恒肉鸡代谢能的测定及近红外预测模型的构建

本试验旨在评定30种不同来源玉米对大恒肉鸡的代谢能值,并利用近红外光谱技术建立近红外预测模型。试验采用单因素完全随机设计,每个玉米样品为1个处理,每个处理8个重复,每个重复1只鸡,采用17周龄大恒肉公鸡。采用排空强饲法评定代谢能;结合近红外光谱,建立大恒肉鸡的玉米代谢能预测模型。结果表明:1)30种玉米的代谢能(DM)为86.76%±0.56%;粗蛋白(CP)为7.99%±0.43%;总能(GE)为16.239±0.123 MJ/kg;中性洗涤纤维(NDF)为11.27%±1.89%;酸性洗涤纤维(ADF)为2.80%±0.39%;粗纤维(CF)为1.98%±0.23%。2)30种玉米对大恒肉鸡的表观代谢能(AME)为14.624±0.469 MJ/kg;氮校正表观代谢能(AMEn)为14.646±0.462 MJ/kg;真代谢能(TME)为16.062±0.488 MJ/kg;氮校正真代谢能(TMEn)为16.083±0.481 MJ/kg。3)用近红外技术建立的大恒肉鸡AME、AMEn、TME、TMEn校正模型决定系数(R2cal)、预测标准差(RMSEE)及相对标准差(RSD)分别为0.99、0.023、0.16;0.99、0.011、0.07;0.99、0.014、0.08;0.99、0.013、0.08;内部交叉验证决定系数(R2cv)及内部交叉验证预测标准差(RMSECV)、相对标准差(RSD)分别为0.93、0.057、0.39;0.95、0.048、0.33;0.94、0.056、0.35;0.95、0.055、0.34。结果表明不同来源玉米对大恒肉鸡的AME、AMEn、TME、TMEn均存在差异。2)构建的近红外预测模型可以较好地预测大恒肉鸡的玉米代谢能值。     

青脚麻肉鸡对不同来源玉米的代谢能值及近红外预测模型的构建

本试验旨在评定青脚麻肉鸡对30个不同来源玉米的代谢能值,并利用近红外光谱技术构建代谢能值的预测模型,为构建青脚麻肉鸡饲料营养价值数据库和玉米代谢能值的快速预测积累基础数据。试验采用单因素完全随机设计,选用48只体重相近的30周龄青脚麻肉公鸡,按照组间体重无差异原则随机分组,做9批次代谢试验,每批做3或4个玉米样,每样设8个重复,每个重复1只鸡;每批做1个内源组,每批之间设10 d恢复期。试验采用排空强饲法测定代谢能值,试鸡饥饿48 h,然后按体重2%强饲待测饲料,收集排泄物48 h;内源组鸡饥饿48 h,再继续饥饿收集排泄物48 h。结果显示:1)30个玉米样品的干物质含量为(86.75±0.55)%(85.55%~87.79%),以干物质为基础,粗蛋白质含量为(9.21±0.52)%(8.27%~10.58%),总能为(18.716±0.106)MJ/kg(18.429~18.951 MJ/kg),中性洗涤纤维含量为(13.00±2.21)%(10.00%~18.52%),酸性洗涤纤维含量为(3.23±0.46)%(2.37%~4.36%),粗纤维含量为(2.28±0.28)%(1.89%~2.76%)。2)以干物质为基础,青脚麻肉鸡对30种玉米的表观代谢能(AME)为(14.627±0.655)MJ/kg(11.727~16.225 MJ/kg),氮校正表观代谢能(AMEn)为(14.672±0.641)MJ/kg(11.793~16.248 MJ/kg),真代谢能(TME)为(16.248±0.619)MJ/kg(13.333~17.727 MJ/kg),氮校正真代谢能(TMEn)为(16.293±0.605)MJ/kg(13.398~17.750 MJ/kg)。3)用近红外光谱技术建立的青脚麻肉鸡AME、AMEn、TME、TMEn校正决定系数(R2cal)、校正标准差(RMSEE)及相对标准差(RSD)分别为0.99、0.035、0.24,0.99、0.029、0.20,0.99、0.031、0.19,0.99、0.030、0.18;交叉验证决定细数(R2cv)、交叉验证标准差(RMSECV)及RSD分别为0.92、0.117、0.80,0.93、0.106、0.73,0.90、0.113、0.70,0.91、0.108、0.66。结果表明:1)青脚麻肉鸡对不同来源玉米的AME、AMEn、TME和TMEn存在差异;2)近红外模型可以较好地预测青脚麻肉鸡的玉米代谢能值。     

生物秸秆对肉鸡表观代谢能的影响及替代玉米适宜比例的研究

本试验旨在研究肉鸡对生物秸秆的表观代谢能及其替代玉米的适宜比例.生物秸秆代谢能的测定试验选择24只42日龄健康的爱拔益加(AA)肉鸡,随机分为3个处理,每个处理8只鸡.处理1饲喂含8％生物秸秆的基础饲粮,处理2饲喂以30％的生物秸秆代替基础饲粮中能量饲料和蛋白质饲料的饲粮,处理3采用强饲法进行测定.生物秸秆代替玉米的试验选择150只42日龄健康的AA肉鸡,随机分为5个处理,每个处理5个重复,每个重复6只鸡.对照组饲喂基础饲粮,试验组分别在基础饲粮中用4％、8％、12％生物秸秆代替玉米(代谢能按照差量法计算结果12.46 MJ/kg计)及8％生物秸秆代替玉米(代谢能按照强饲法计算结果5.30 MJ/kg计,添加豆油,使其代谢能水平与对照组相同).结果表明:1)基础饲粮的代谢能为12.63 MJ/kg,采用差量法推算出肉鸡对生物秸秆的表观代谢能为12.46 MJ/kg,而采用套算法和强饲法测定生物秸秆的表观代谢能分别为4.38和5.30 MJ/kg.2)与对照组相比,4％和8％的生物秸秆代替玉米组中性洗涤纤维和酸性洗涤纤维的代谢率显著升高(P＜0.05),而12％的生物秸秆代替玉米组表观能量的代谢率显著降低(P＜0.05).由此得出,套算法和强饲法低估了生物秸秆的表观代谢能,而差量法更能准确反映生物秸秆的表观代谢能;在肉鸡饲粮中生物秸秆可以替代4％ ～8％的玉米.     

Nutritional value of a partially defatted and a highly defatted black soldier fly larvae(Hermetia illucens L.) meal for broiler chickens: apparent nutrient digestibility,apparent metabolizable energy and apparent ileal amino acid digestibility

Background: The study aimed to determine the apparent total tract digestibility coefficients(ATTDC) of nutrients, the apparent metabolizable energy(AME and AMEn) and the amino acid(AA) apparent ileal digestibility coefficients(AIDC)of a partially defatted(BSFp) and a highly defatted(BSFh) black soldier fly larvae meal. The experimental diets were: a basal diet and two diets prepared by substituting 250 g/kg(w/w) of the basal diet with BSFp or BSFh, respectively.Results: Significant differences were found between BSFp and BSFh meals for ATTDC of the nutrients: BSFp resulted more digestible than BSFh, except for ATTDC of CP which did not differed between meals, while a statistical trend was observed for ATTDC of DM and EE. The AME and AMEn values were significantly(P 0.05) different between the two BSF meals, with higher levels for BSFp(16.25 and 14.87 MJ/kg DM, respectively). The AIDC of the AA in BSFp ranged from 0.44 to 0.92, while in BSFh they ranged from 0.45 to 0.99. No significant differences were observed for the AA digestibility(0.77 and 0.80 for BSFp and BSFh, respectively), except for glutamic acid, proline and serine that were more digestible in the BSFh meal(P 0.05).Conclusions: Defatted BSF meals can be considered as an excellent source of AME and digestible AA for broilers with a better efficient nutrient digestion. These considerations suggested the effective utilization of defatted BSF larvae meal in poultry feed formulation.     

The correlationship between the metabolizable energy content,chemical composition and color score in different sources of corn DDGS

Background： This study was conducted to evaluate the apparent metabolizable energy （AME） and true metabolizable energy （TME） contents in 30 sources of corn distillers dried grains with solubles （DDGS） in adult roosters, and establish the prediction equations to estimate the AME and TME value based on its chemical composition and color score. Methods： Twenty-eight sources of corn DDGS made from several processing plants in 11 provinces of China and others imported from the United States. DDGS were analyzed for their metabolizable energy （ME） contents, measured for color score and chemical composition （crude protein, crude fat, ash, neutral detergent fiber, acid detergent fiber）, to predict the equation of ME in DDGS. A precision-fed rooster assay was used, each DDGS sample was tube fed （50 g） to adult roosters. The experiment was conducted as a randomized incomplete block design with 3 periods. Ninety-five adult roosters were used in each period, with 90 being fed the DDGS samples and 5 being fasted to estimate basal endogenous energy losses. Results： Results showed that the AME ranged from 5.93 to 12.19 MJ/kg, TME ranged from 7.28 to 13.54 MJ/kg. Correlations were found between ME and ash content （-0.64, P 〈 0.0]） and between ME and yellowness score （0.39, P 〈 0.05） of the DDGS samples. Furthermore, the best-fit regression equation for AME content of DDGS based on chemical composition and color score was AME = 6.57111 ＋ 0.5]475 GE - 0.10003 NDF ＋ 0.1 3380 ADF ＋ 0.07057 fat - 0.57029 ash - 0.02437 L （R^2 = 0.70）. The best-fit regression equation for TME content of DDGS was TME = 7.92283 ＋ 0.51475 GE - 0.10003 NDF ＋ 0.13380 ADF ＋ 0.07057 fat - 0.57029 ash - 0.02437 L （R2 = 0.70）. Conclusions： This experiment suggested that measuring the chemical composition and color score of a corn DDGS sample may provide a quality parameter for identifying corn DDGS sources energy digestibility and metabolizable energy content.     

不同处理玉米秸秆营养成分及其肉鸡表观代谢能评定

本试验旨在评价不同处理玉米秸秆营养成分及其肉鸡表观代谢能。选择40只42日龄健康AA商品肉鸡,随机分为8个处理,每个处理5只鸡。直接法分为3个处理组,分别为强饲15 g 100%未处理秸秆、50 g 100%糖化秸秆、50 g 100%酵母发酵秸秆;差量法分为5个处理组,即基础饲粮组和试验组。试验组分别在基础饲粮中添加4%、8%、12%糖化玉米秸秆和8%酵母发酵秸秆替代等量玉米。通过饲养试验验证差量法和直接法对糖化玉米秸秆代谢能测定的准确性。结果表明:与未处理玉米秸秆相比,糖化秸秆中还原糖和钙含量分别增加8.08倍和9.31倍(P<0.05);与糖化玉米秸秆相比,酵母发酵秸秆中还原糖降低78.69%(P<0.05),真蛋白提高29.64%(P<0.05),总氨基酸提高41.01%(P<0.05);通过直接法得出糖化玉米秸秆和酵母发酵玉米秸秆的表观代谢能分别为4.85、4.75 MJ/kg;差量法测定糖化玉米秸秆在饲粮中添加4%、8%和12%时表观代谢能分别为15.85、15.81、14.38 MJ/kg,高于酵母菌发酵玉米秸秆(P<0.05);通过饲养试验验证,差量法测定的表观代谢能结果可信。结果显示,糖化玉米秸秆代谢能高于酵母发酵秸秆和玉米,可以作为肉鸡的饲料能量原料。     

Apparent metabolisable energy and amino acid digestibility of microalgae Spirulina platensis as an ingredient in broiler chicken diets

ABSTRACT

1. This work investigates the apparent metabolisable energy (AME), its nitrogen-corrected form (AMEn) and amino acid (AA) digestibility coefficients of the microalgae Spirulina platensis as an ingredient in broiler chicken diets.

2. One group of birds was fed with a basal control diet (BD), and another was fed with a test diet composed of the BD with the addition of the microalgae at a proportion of 200 g/kg. AME and AMEn were assessed by total excreta collection and indigestibility analysis using acid-insoluble ash (AIA) as a marker.

3. The microalgae comprised 888.0 g/kg dry matter (DM), 18.42 MJ/kg gross energy, 514.7 g/kg crude protein, 9.9 g/kg ether extract, 10.6 g/kg crude fibre, 94.4 g/kg ash, 3.1 g/kg Ca and 11.0 g/kg P.

4. The values obtained for AME (13.48 MJ/kg DM) and AMEn (11.72 MJ/kg DM) were higher (p < 0.01) than those obtained using the AIA method (9.39–8.29 MJ/kg DM). The microalgae ileal digestibility coefficients were 0.80 ± 0.04 and 0.78 ± 0.04 for essential and non-essential AA, respectively.

5. Overall, the metabolisable energy content and digestibility of AA for S. platensis indicated that the microalgae are potentially an alternative nutrient source for broilers. The AIA method underestimated AME and AMEn in comparison to the total excreta collection method.     

The energy content of barley fed to growing pigs: characterizing the nature of its variability and developing prediction equations for its estimation.

Currently, the pork industry attempts to formulate energy levels in swine diets to within a tolerance of 1.5%. This is difficult to achieve in practice when the energy content of primary ingredients fluctuates by up to 15%. This experiment was carried out to define the sources of variation in the energy content of barley and to develop a practical method to accurately estimate the DE and ME content of individual barley samples. Four samples of each of five covered barley varieties (AC Lacombe, B-1602, Bedford, Harrington, and Manley) were collected to obtain a range of quality within each variety. Five measurements were collected on each barley sample using 60 crossbred barrows in an apparent total tract digestibility study. The barrows, average BW of 35.3 kg, were housed in individual metabolism crates to facilitate separate collection of urine and feces. Five-day collection periods followed 5-d diet acclimation periods. Levels of total beta-glucan, ADF, CP, and starch (90% DM) in the 20 barley samples ranged from 2.7 to 4.5%, 4.5 to 9.2%, 10.8 to 15.1%, and 42.3 to 53.4%, respectively. The mean DE and ME content of the 20 samples were 2,934 and 2,857 kcal/kg (90% DM), respectively, and varied among samples by 15.2% (447 kcal). The complex structural cell wall carbohydrates seemed to have the greatest influence on the energy content of individual barley samples. The ADF fraction alone accounted for 85% of the total variation in energy content of the 20 samples. Converted into a prediction equation, DE = 3,526 - 92.8 x ADF (90% DM), the ADF content was used to estimate the DE content of barley with 85% accuracy. This experiment confirms the large variation in the energy content of barley, describes the factors that influence this variation, and presents equations based on chemical and(or) physical measurements that may be used to predict the DE and ME content of individual barley samples.     

European reference method of in vivo determination of metabolisable energy in poultry: reproducibility, effect of age, comparison with predicted values

1. Apparent metabolisable energy corrected to zero-nitrogen retention (AMEn) was measured using the European reference procedure in 9 European laboratories. Seven pelleted diets were evaluated. AMEn was measured with adult cockerels and young birds. 2. Between-laboratory standard deviations were for dry matter (DM) 12.5 g/kg, gross energy 0.085 MJ/kg DM, Kjeldahl nitrogen 0.768 g/kg DM, AMEn (adults) 0.256 MJ/kg DM, and AMEn (young) 0.337 MJ/kg DM. Corresponding coefficients of variation between laboratories were 1.42, 0.45, 2.15, 1.88 and 2.60% respectively. 3. AMEn values of experimental diets were always significantly lower when measured with young birds. This effect was more pronounced when diets contained added fat. 4. Tallow or soyabean oil were incorporated into two basal diets at 40 g/kg inclusion rate. No significant differences were observed between AMEn values of either diet with adults or young birds, suggesting that AMEn energy values of these fats are indistinguishable at this inclusion rate. 5. Similar AMEn values were obtained in young birds by estimating nitrogen accretion, either by the difference between intake and excreta nitrogen or by measuring body weight gain. Determined AMEn values were very similar to those predicted using three different regression equations.