Neal H D, Dijkstra J, Gill M
AFRC Institute of Grassland and Environmental Research, Hurley, Maidenhead, Berkshire, U.K.
J Nutr. 1992 Nov;122(11):2257-72. doi: 10.1093/jn/122.11.2257.
A mathematical model of the rumen fermentation processes constructed to predict nutrient supply to the host animal was evaluated. Sensitivity analysis on high fiber, starch and protein diets indicated that the model responds appropriately to these types of diets and to changes in parameter values, and revealed that the model is sensitive to the availability of hexose for non-growth microbial processes and to the maximum storage rate of polysaccharides in amylolytic microbes, although sensitivity varied with diet composition. Of the parameters whose values were dependent on diet, the fraction of protozoa in the amylolytic microbial pool and the fluid and solid passage rates needed the most careful estimation. When model predictions of nutrient supply were compared with the experimental observations, those for duodenal flows of neutral detergent fiber, total non-ammonia nitrogen (NAN) and total volatile fatty acid rumen concentration were satisfactory for several feeding strategies. The partition of NAN flow into microbial and non-microbial NAN flow and the molar proportions of volatile fatty acid production and concentration were not predicted well. The representation of the complex interactions between rumen microbial populations and of their effects on the production of specific volatile fatty acids merits further study for an improvement in the prediction of nutrient supply.
对一个构建用于预测宿主动物养分供应的瘤胃发酵过程数学模型进行了评估。对高纤维、淀粉和蛋白质日粮的敏感性分析表明，该模型能对这些类型的日粮以及参数值的变化做出适当响应，并揭示出该模型对非生长微生物过程中己糖的可用性以及淀粉分解微生物中多糖的最大储存速率敏感，尽管敏感性会因日粮组成而有所不同。在其值取决于日粮的参数中，淀粉分解微生物池中原生动物的比例以及液体和固体通过速率需要最仔细的估算。当将养分供应的模型预测与实验观察结果进行比较时，对于几种饲养策略，十二指肠中性洗涤纤维流量、总非氨氮（NAN）和瘤胃总挥发性脂肪酸浓度的预测结果令人满意。NAN流量在微生物和非微生物NAN流量之间的分配以及挥发性脂肪酸产生和浓度的摩尔比例预测得并不好。瘤胃微生物种群之间复杂相互作用及其对特定挥发性脂肪酸产生影响的表征，值得进一步研究以改进养分供应的预测。
