Growing importance of upcycling agricultural by-products, food waste, and food processing by-products through livestock production strongly increased the variation in the nutritional quality of feed ingredients. Traditionally, feed ingredients are evaluated based on their measured extent of digestion. Awareness increases that in addition to the extent, the kinetics of digestion affects the metabolic fate of nutrients after absorption. Together with a growing body of evidence of complex interactions occurring within the lumen of the digestive tract, this urges the need of developing new approaches for feed evaluation. In a recently developed approach, we propose combining in vitro and in silico methods for feed ingredient evaluation. First steps in the development of such a systems were made by (1) evaluating in vitro the digestion potential of feed ingredients, regarding this as true ingredient properties and (2) predicting in silico the digestive processes like digesta transit, nutrient hydrolysis and absorption using dynamic, mechanistic modeling. This approach allows to evaluate to what extent the digestion potential of each ingredient is exploited in the digestive tract. Future efforts should focus on modeling digesta physicochemical properties and transit, applying in vitro digestion kinetic data of feed ingredients in mechanistic models, and generating reliable in vivo data on nutrient absorption kinetics across feed ingredients. The dynamic modeling approach is illustrated by a description of a modeling exercise that can be used for teaching purposes in digestive physiology or animal nutrition courses. A complete set of equations is provided as an on-line supplement, and can be built in modeling software that is freely available. Alternatively, the model can be constructed using any modeling software that enables the use of numerical integration methods.

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ASAS-NANP 研讨会：猪的消化动力学：饲料评估的下一步和即用型建模练习

通过畜牧生产对农业副产品、食物垃圾和食品加工副产品进行升级循环的重要性日益增加，这大大增加了饲料成分营养质量的变化。传统上，饲料成分是根据它们测量的消化程度来评估的。人们越来越意识到，除了程度之外，消化动力学还会影响吸收后营养物质的代谢命运。再加上越来越多的证据表明消化道内腔内发生了复杂的相互作用，这就迫切需要开发新的饲料评估方法。在最近开发的一种方法中，我们建议结合体外和计算机方法进行饲料成分评估。开发此类系统的第一步是通过（1）在体外评估饲料成分的消化潜力，将其视为真正的成分特性；（2）使用计算机预测消化过程，如食糜转运、营养水解和吸收动态，机械建模。这种方法可以评估每种成分的消化潜力在消化道中的利用程度。未来的工作应侧重于对食糜理化性质和转运进行建模，在机械模型中应用饲料成分的体外消化动力学数据，并生成有关饲料成分营养吸收动力学的可靠体内数据。动态建模方法通过对可用于消化生理学或动物营养课程教学目的的建模练习的描述来说明。一套完整的方程作为在线补充提供，并且可以内置在免费提供的建模软件中。或者，可以使用任何能够使用数值积分方法的建模软件来构建模型。