基于CNCPS-S模型对全混合日粮蛋白质在绵羊瘤胃内有效降解率的预测研究

Prediction of effective degradation rate of total mixed ration protein in rumen of sheep based on CNCPS-S model

研究旨在应用瘤胃尼龙袋法验证康奈尔净碳水化合物和净蛋白质绵羊体系(CNCPS-S)蛋白质瘤胃降解预测模型的适用性。选取3只安装永久性瘤胃瘘管的哈萨克去势公羊作为试验动物,应用尼龙袋法测定全混合日粮(TMR)蛋白质组分的瘤胃动态降解率,并对蛋白质组分的瘤胃降解速率进行最小二乘估计,对TMR的食糜外流速度(Kp)进行实测和预测,最后得出蛋白质瘤胃降解模型适用性的验证结果。结果表明:①TMR1和TMR2的Kp预测值均显著低于实测值(P<0.05);②3种TMR之间的蛋白质瘤胃有效降解率的实测值差异不显著(P>0.05),蛋白质瘤胃降解率预测值差异极显著(P<0.01),表现为TMR1>TMR3>TMR2;③改良后的蛋白质瘤胃降解模型显示预测值和实测值平均偏差较低;相关系数范围在0.55~0.84之间;斜率接近1;均方根误差较低。以上结果说明CNCPS-S对绵羊CP瘤胃降解率具有较好的预测能力。

The purpose of this experiment was to verify the applicability of the prediction model of rumen degradation of protein in Cornell Net Carbohydrate and Net Protein System for sheep(CNCPS-S) by using nylon bag technique. Three Kazakh castrated rams with permanent rumen fistula were selected as experimental animals, the rumen degradation rate of protein components in TMR was measured by nylon bag method, and the rumen degradation rate constant of protein components was estimated by least square method. The outflow rate of rumen digesta(Kp) was measured and predicted. Finally, the applicability of protein rumen degradation model was verified. The results showed that: ① The predicted values of outflow rate of rumen digesta of TMR1 and TMR2 were significantly lower than the observed values(P<0.05);② There was no significant difference between the three TMRs in rumen effective degradation rate(P>0.05), and the difference between the predicted values of the rumen degradation rate was very significant(P<0.01), which was TMR1>TMR3>TMR2;③ The improved rumen degradation model of protein showed that the mean deviation between the predicted value and the observed value was low;the correlation coefficient ranged from 0.55 to 0.84;the slope was close to 1;and the RMSE was low. These results indicate that CNCPS-S has a good prediction ability for rumen degradation rate of CP in sheep.