Matrix values for exogenous enzymes and their application in the real world

摘要

The use of enzymes in commercial practice is most often associated with the application of a nutrient matrix to account for the expected effects. Such matrices are determined by a number of different methods and in many cases digestibility and/or performance trials are employed. Each has its limitations, but particular care must be taken if digestibility trials are used in isolation as they ignore intake and postabsorptive effects. Moreover, the response to a feed enzyme is very much dependent upon a multitude of environmental, dietary, and husbandry–related factors, and as a consequence, the commercial nutritionist should take into consideration the divergence between the conditions of the assay used to generate a matrix and the conditions under which the enzyme will be employed. In their application, nutrient matrices assigned to enzymes may not necessarily reduce costs as expected if ingredient constraints (e.g. min fat concentration) prevent reductions in expensive, nutrient rich ingredients. Furthermore, most enzymes are formulated in at a fixed dose, but this limits their value as the majority tend to release nutrients in a log dose: linear nutrient release relationship. Methods to take such an effect into account exist and enable true least cost formulation of the enzyme as an ingredient. Finally, often a commercial ration may employ 3 enzymes, each of which has an associated energy matrix, for example. Even though the mechanisms through which they deliver this value may be different, it is prudent to ensure that their matrices are truly additive before application in the field.