利用净碳水化合物-蛋白质体系组分估测肉牛日粮营养物质全消化道表观消化率研究

Estimation of Total Tract Apparent Digestibility of Nutrients in Beef Diets Using CNCPS

本研究旨通过测定康奈尔净碳水化合物-蛋白质体系(Cornell net carbohydrate and protein system,CNCPS)组分和日粮常规营养物质全消化道表观消化率,建立根据肉牛日粮CNCPS组分预测主要营养成分消化率的数学模型。本研究以4头15月龄的安格斯×鲁西黄牛杂交一代阉公牛[体重(311±22)kg]作为试验动物,采用3×4不完全拉丁方设计,配制高(H)、中(M)、低(L)3种不同能量水平但蛋白质水平基本一致的日粮。测定3种试验日粮CNCPS组分,并采用全收粪法测定常规营养成分全消化道表观消化率。结果表明:日粮含氮化合物组分与肉牛日粮干物质(dry matter,DM;R2=0.95,P<0.01)、有机物(organic matter,OM;R2=0.90,P<0.01)、粗蛋白质(crude protein,CP;R2=0.88,P<0.01)和酸性洗涤纤维(acid detergent fiber,ADF;R2=0.81,P<0.05)的全消化道消化率之间都存在着显著的多元回归关系,日粮碳水化合物组分与肉牛日粮DM(R2=0.90,P<0.01)和OM(R2=0.82,P<0.01)的全消化道消化率之间存在着显著的多元回归关系。证明CNCPS组分估算日粮常规营养成分消化率具有一定的可行性。

This experiment was conducted to establish the mathematical model to estimate the digestibility of nutrients by the Cornell net carbohydrate and protein system（CNCPS）composition in the beef diets.In this experiment,four castrated beef bulls of the F1 generation from Angus×Luxi yellow cattle,which were 15 months old and weighed（311±22）kg,were used by 3×4 incomplete Latin square design.There were three different diets containing high（H）,middle（M）,low（L）energy level,respectively.But the contents of crude protein in three diets were the same.The compositions of CNCPS in different diets were determined.All the feces were collected to determine the total tract apparent digestibility of nutrients.The results showed that there were significant multiple regression relationships between nitrogenous compound and the digestibility of DM（R2=0.95,P0.01）,OM（R2=0.90,P0.01）,CP（R2=0.88,P0.01）and ADF（R2=0.81,P0.05）in beef diets,and there were significant multiple regression relationships between carbohydrate and the total tract apparent digestibility of DM（R2=0.90,P0.01）and OM（R2=0.82,P0.01）in beef diets.The results suggested that CNCPS could be used to estimate the total tract apparent digestibility of nutrients in beef diets.