应用康奈尔净碳水化合物-蛋白质体系和NRC模型比较常用粗饲料和玉米纤维饲料的营养价值

Comparison of Nutrition Values of Dry Corn Gluten Feed and Commonly Used Roughages using Cornell Net Carbohydrate-Protein System and National Research Council Models

本试验旨在应用康奈尔净碳水化合物-蛋白质体系(CNCPS)和NRC模型比较玉米纤维饲料(DCGF)与奶牛常用粗饲料(苜蓿、玉米青贮、羊草)营养价值,进而分析DCGF作为奶牛纤维饲料资源的可行性。采集东北地区不同牧场的饲料样本,测定营养成分后利用CNCPS模型对各饲料蛋白质和碳水化合物进行剖分,并预测各饲料对奶牛的潜在营养物质供给量,同时利用NRC模型对4种饲料的可消化养分和能值进行估测计算。结果表明:1)DCGF中粗蛋白质(CP)含量显著高于玉米青贮和羊草(P<0.05),中性洗涤纤维(NDF)含量显著高于苜蓿(P<0.05),且酸性洗涤纤维(ADF)、酸性洗涤木质素(ADL)含量显著低于其他3种粗饲料(P<0.05)。2)DCGF快速降解真蛋白质(PB1)和中速降解真蛋白质(PB2)含量显著低于苜蓿(P<0.05);中速降解碳水化合物(CB1)和慢速降解碳水化合物(CB2)含量显著高于其他3种粗饲料(P<0.05)。3)苜蓿的可代谢蛋白质(MP)含量最高,其次为DCGF。4)DCGF在维持水平下总可消化养分(TDNm)和净能均最高。结果提示,DCGF具有较高的营养价值,可以作为奶牛纤维类高蛋白质饲料替代奶牛饲粮中部分粗饲料,缓解我国优质粗饲料、蛋白质饲料资源紧缺的压力。

The aim of this study was to compare the nutrition values of dry corn gluten feed（ DCGF） and commonly used roughages for dairy cattle（ alfalfa hay,corn silage and wildrye） using Cornell net carbohydrate-protein system（ CNCPS） and National Research Council（ NRC） models,and to analyze the feasibility of DCGF as fiber source for dairy cattle. Feed samples were collected from different farms and then nutrient composition was determined. The protein and carbohydrate fractions were partitioned using CNCPS. At the same time,NRC models were used to predict the digestible nutrient contents and energy values of four kinds of feedstuffs. The results showed as follows： 1） the content of crude protein（ CP） of DCGF was significantly higher than those of corn silage and wildrye（ P〈 0. 05）,and the content of neutral detergent fiber（ NDF） was significantly higher than that of alfalfa hay（ P〈 0. 05）,however,the contents of acid detergent fiber（ ADF） and acid detergent lignin（ ADL） of DCGF were significantly lower than those of other three kinds of roughages（ P 〈0. 05）. 2） The contents of rapidly degraded true protein（ PB1） and intermediately degraded true protein（ PB2） factions of DCGF were significantly lower than those of alfalfa hay（ P〈 0. 05）,and the contents of intermediately degraded carbohydrate（ CB1） and slowly degraded carbohydrate（ CB2） of DCGF were significantly higher than those of other roughages（ P〈 0. 05）. 3） The content of metabolizable protein（ MP） of alfalfa hay was the highest,and DCGF was at second. 4） Compared with other three kinds of roughages,the truly digestible nutrients at maintenance level and energy values for DCGF were the highest. The results indicate that DCGF has relatively high nutrition values and can be used in dairy cattle diet as fiber feed instead of parts of roughages to relieve the pressure of high quality roughage and protein feeds shortage.