近红外光谱法测定紫花苜蓿青贮鲜样的营养价值

应用近红外光谱技术(NIRS)直接分析新鲜饲草的营养价值,如饲草中干物质(DM),粗蛋白(CP),中性洗涤纤维(NDF),酸性洗涤纤维(ADF)含量,对畜牧业生产具有重要意义.鲜草中由于含有较多的水分,不易制备均一的样品和进行光谱中有用信息的提取,因此难于进行近红外光谱分析.本试验应用偏最小二乘回归法(PLS)、傅里叶变换近红外光谱技术和液氮冷冻制样技术,建立了适合于不同品种,不同生育期,不同茬次和不同青贮方法即时测定青贮苜蓿鲜样中DM,CP,NDF,ADF的模型,以期对NIRS在测定紫花苜蓿青贮鲜样品这些成分测定的可行性进行分析.所建DM,CP,NDF和ADF模型的交叉检验决定系数(R2cv)为0.884 6～0.989 8,交叉检验标准误(RMSECV)为3.9～9.7 g·kg-1鲜重.用50个样品对模型进行外部检验,预测相关系数(r)为0.939 7～0.994 9,预测标准误为1.9～8.3 g·kg-1鲜重.结果表明:采用适当的样品处理方法和光谱分析技术可以实现近红外光谱技术对苜蓿青贮鲜样的营养价值评定.

Evaluation of Fresh Sample of Alfalfa Silage Through Near Infrared Reflectance Spectroscopy (NIRS)

It is very important to evaluate the fresh sample of alfalfa silage using near infrared reflectance spectroscopy technology (NIRS) for animal production. The nutrient content of forage means the contents of dry matter (DM), crude protein (CP), neutral detergent fiber (NDF), and acid detergent fiber (ADF) in the forage. Because of the high moisture content, it is difficult to make uniform samples for fresh forage and to get useful information from the spectrum. Therefore, it is hard to use NIRS analysis. In order to evaluate the feasibility of using NIRS to analyse the fresh alfalfa silage, the DM, CP, NDF and ADF contents of fresh alfalfa silage were evaluated by the near infrared reflectance spectroscopy model in this experiment using partial least square regression (PLS), Fourier transform technology and sample preparation with liquid nitrogen technology. The analysis samples were obtained through different cultivars, maturity, cuttings and ensiling method. The cross validation was determined between 0.884 6-0. 989 8. The standard error of cross validation was between 3.9 and 9.7 g x kg(-1) fresh weight. Fifty samples were used to test the performance of the models. The coefficients of correlation between the chemical value and the NIRS value are between 0.939 7 and 0.994 9, and the root mean square errors of prediction are between 1.9 and 8.3 g x kg(-1) fresh weight. The results showed that NIRS could be used to evaluate the nutrition of fresh forage.