瘤胃淀粉消化率及消化动力学的研究方法评述

文章探讨了研究瘤胃淀粉消化率及消化动力学的方法存在的缺陷。淀粉消化位点及该位点的消化率对反刍动物从消化道吸收养分的数量和形式具有重大影响。通过皱胃或十二指肠瘘管收集的食糜样品缺乏代表性,而双相指示剂法也不能完全解决这个问题。原位法被广泛应用于瘤胃淀粉消化速率的测定,但关于从尼龙袋中消失的物质被发酵的假设仍有待商酌。并且,原位法一次函数的假设也受到质疑,说明根据消化动力学参数估计瘤胃淀粉消化率的模型需要完善。体外法以反应体系中淀粉消失率或产气量为基础来评估淀粉消化速率,其重要前提是淀粉消化速率不能受反应体系限制。

A comment on methods for estimating starch digestibility and digestion kinetics in the rumen

The objective of the paper is to discuss the disadvantages concerning the methods used to estimate starch digestibility and digestion kinetics in the rumen. Starch digestibility and site of starch digestion have a profound effect on the amount and profile of substrates absorbed from the digestive tract in ruminants. The double-marker technique does not solve the problems related to unrepresentative digesta sampling from an abomasal or a duodenal cannula. The in situ technique is the most widely used method to estimate digestion rate of starch. The major problem of the technique is that it is based on the assumption that material disappearing from the bags is fermented, which is often not the case. The pas- sage of particles rich in starch do not follow the first-order passage kinetics. This means that the models used to estimate ruminal starch digestibility from the kinetic parameters are incomplete. Starch degrada- tion is commonly measured in vitro either directly by measuring starch disappearance after incubation for various time intervals or indirectly by measuring gas production. A requisite of the in vitro tech- niques in estimating the rate of starch digestion is that the system itself is not limiting.