Schofield P, Pell A N
Department of Animal Science, Cornell University, Ithaca, NY 14853, USA.
J Anim Sci. 1995 Nov;73(11):3455-63. doi: 10.2527/1995.73113455x.
The fermentation of the neutral detergent-soluble (NDS) fraction of two legumes (clover, alfalfa) and two grasses (timothy, guinea grass) was measured using a curve subtraction technique with in vitro gas production data from the whole forage and the isolated neutral detergent-extracted fiber. The NDF disappearance and VFA production also were measured. There were no significant differences between the VFA patterns from whole forage and NDF. There was a good linear correlation between the volume of gas produced and the mass of fiber digested in the NDF samples. Analysis of the gas curves with a dual-pool logistic model gave a lag value, digestion rates and pool sizes for the whole forage, the fiber component, and the NDS fraction. Rates for the NDS fraction ranged from .152 h-1 for clover to .191 h-1 for timothy. These rates are appreciably lower than values assumed in some models. Application of a triple-pool logistic model revealed the presence of faster-digesting material in the legumes. We discuss several different ways to measure the NDS pool size. The simplest method requires only a single gas measurement at the end of in vitro digestion of the whole forage coupled with an NDF disappearance measurement. The curve subtraction technique can provide information on the size and digestion kinetics of the NDS pool. This information is useful both for model studies and for agronomic research and may help us to understand the nutritional significance of this fast-digesting carbohydrate fraction.
采用曲线减法技术，利用全株牧草和分离出的中性洗涤纤维体外产气数据，测定了两种豆科植物（三叶草、苜蓿）和两种禾本科植物（猫尾草、几内亚草）中性洗涤可溶性（NDS）部分的发酵情况。还测定了中性洗涤纤维（NDF）消失率和挥发性脂肪酸（VFA）产量。全株牧草和NDF的VFA模式之间没有显著差异。NDF样品中产气量与纤维消化量之间存在良好的线性相关性。用双池逻辑模型分析气体曲线，得出了全株牧草、纤维成分和NDS部分的滞后值、消化率和池大小。NDS部分的消化率范围从三叶草的0.152 h-1到猫尾草的0.191 h-1。这些速率明显低于一些模型中假设的值。应用三池逻辑模型揭示了豆科植物中存在消化更快的物质。我们讨论了几种测量NDS池大小的不同方法。最简单的方法只需要在全株牧草体外消化结束时进行一次气体测量，并结合NDF消失率测量。曲线减法技术可以提供有关NDS池大小和消化动力学的信息。这些信息对于模型研究和农艺研究都很有用，可能有助于我们理解这种快速消化碳水化合物部分的营养意义。
