Systems to measure energy value of poultry feeds

Abstract

This review is concerned about the different systems and methods available to measure the energy values of feeds and ingredients for poultry. The aspects developed in the first part related with the direct methods regularly used to measure metabolisable energy (EM), reporting some of the advantages and disadvantages of using conventional methods or rapid assays. Results are given on the relationship between TME (True Metabolisable Energy) and AME (Apparent Metabolisable Energy) in diets with higher non-starch-polysaccharides. A common reference procedure adopted by several European laboratories to determine apparent metabolisable energy corrected to zero-nitrogen balance (AMEn) is described. In a second part, the use of alternative methods, such as indirect or in-vitro methods, available in the literature are reported. This review includes in-vitro digestion systems, prediction equations on the basis of crude nutrients or digestible nutrients and the use of Near Infrared Reflectance Spectroscopy analysis to predict the energy content of feeds, ingredients or the gross energy of excreta. From this paper, it is clear that more studies are needed to define the most suitable method to measure the energy content of poultry diets and, secondly, improve the methods used for prediction of these values for use in feed formulation.