应用康奈尔净碳水化合物-蛋白质体系和NRC模型评价4种粮食加工副产物的营养价值

本试验旨在应用康奈尔净碳水化合物-蛋白质体系(CNCPS)和NRC模型评价4种粮食加工副产物的营养价值。从东北地区4个不同牧场采集了玉米纤维饲料、大豆皮、甜菜粕和豆渣4种粮食加工副产物,测定其营养成分,应用CNCPS模型对蛋白质和碳水化合物组分进行剖分,并预测其潜在营养价值供给量,应用NRC模型估测可消化养分和能值。结果表明:1)中性洗涤纤维(NDF)的含量由高到低依次为大豆皮、甜菜粕、玉米纤维饲料和豆渣;非蛋白氮(NPN)的含量由高到低依次为玉米纤维饲料、豆渣、甜菜粕和大豆皮;甜菜粕的酸性洗涤不溶粗蛋白质(ADICP)含量最高,其余依次为大豆皮、豆渣和玉米纤维饲料,其中玉米纤维饲料和豆渣的ADICP含量差异不显著(P0.05)。2)非蛋白氮(PA,即NPN)含量由高到低依次为玉米纤维饲料、豆渣、甜菜粕和大豆皮;真蛋白质(PB)含量由高到低依次为大豆皮、甜菜粕、豆渣和玉米纤维饲料;不可降解氮(PC)的含量由高到低依次为豆渣、甜菜粕、大豆皮和玉米纤维饲料。3)可代谢蛋白质(MP)含量由高到低依次为豆渣、大豆皮、甜菜粕和玉米纤维饲料。4)玉米纤维饲料和豆渣的维持水平总可消化养分(TDNm)含量较高,二者差异不显著(P0.05);生产水平泌乳净能(NELP)值由高到低依次为豆渣、玉米纤维饲料、大豆皮和甜菜粕,其中玉米纤维饲料的NELP值与豆渣、大豆皮差异均不显著(P0.05);生产水平代谢能(MEP)值由高到低依次为豆渣、玉米纤维饲料、甜菜粕和大豆皮。由此可见,玉米纤维饲料和大豆皮可以作为奶牛的纤维源饲料;豆渣的过瘤胃蛋白质(RUP)、MP含量最高,可以作为奶牛的蛋白质源饲料。4种粮食加工副产物的能值由高到低依次为豆渣、玉米纤维饲料、大豆皮、甜菜粕。

Evaluation of Nutrition Values of 4 Kinds of By-Products of Food Processing Using Cornell Net Carbohydrate and Protein System and National Research Council Models

This study was conducted to evaluate the nutrition values of 4 kinds of by-products of food process-ing using Cornell net carbohydrate and protein system ( CNCPS) and national research council ( NRC) models. Dry corn gluten feed ( DCGF) , soybean hulls ( SH) , sugar beet pulp ( SBP) and bear residue ( BR) from four different pastures in northeast China were collected to determine nutrient compositions, and partition of the protein and carbohydrate subfractions using CNCPS system. The predicted nutrient supply of by-products of food processing was estimated based on CNCPS system. Finally, the digestible nutrient contents and energy values were predicted using NRC models. The results showed as follows:1) the contents of neutral detergent fi-ber ( NDF) from high to low in turn were SH, SBP, DCGF and BR; the contents of non-protein nitrogen ( NPN) from high to low in turn were DCGF, BR, SBP and SH;the content of acid detergent insoluble crude protein ( ADICP) was the highest in SBP, the contents of others from high to low in turn were SH, DCGF and BR, the contents of ADICP in DCGF and BR had no significant difference ( P>0.05) . 2) The contents of non protein nitrogen ( PA) from high to low in turn were DCGF, BR, SBP, SBP and SH;the contents of true pro-tein ( PB) from high to low in turn were SH, SBP, BR and DCGF; the contents of undegradable nitrogen (PC) from high to low in turn were BR, SBP, SH and DCGF. 3) The contents of microbial protein (MP) from high to low in turn were BR, SH, SBP and DCGF. 4) The contents of total digestible nutrients at mainte-nance (TDNm) were higher in DCGF and BR, and there was no significant difference between them (P>0.05); the values of net energy for lactation at production level (NELP) from high to low in turn were BR, DCGF, SH and SBP, and the NELP in DCGF had no significant difference from BR and SH ( P>0.05); the values of the metabolizable energy at production level (MEP) from high to low in turn were BR, DCGF, SBP and SH. The results indicate that DCGF and SH can be used as a fiber source in dairy cattle feed;the contents of rumen bypass protein and MP are highest in BR, which can be used as a protein source in dairy cattle feed. The energy values from high to low in turn are BR, DCGF, SH and SBP.