TP 4: Development of in vitro methods for estimating the digestibility of amino acids from cereal grains

Simple and fast in vitro methods which can be applied, under the conditions of work routine  and which can replace time-consuming and expensive animal experiments to estimate the ileal digestibility of amino acids in feed for pigs and poultry do not exist yet. This is mainly due to the low level data base of in vivo digestibility values from animal experiments as a prerequisite for the validation of the respective in vitro values. Therefore the in vivo data produced in subprojects 1, 2 and 3 with pigs and poultry are the basis for the establishment of species-specific in vitro approaches for the estimation of precaecal digestibility of amino acids in the grain depending on crop type and variety (corn, winter barley, winter wheat, winter triticale, winter rye and, if necessary oats in horse). After validation, the database was expanded significantly by the extension of the in vitro studies on defined grain lots that were provided by the participating plant breeding companies. Supplemented by the results from the chemical-analytical characterization (Z-project) the subproject-specific in vivo and in vitro data were the basis for deriving regression equations to estimate the levels of digestible protein and digestible amino acids in grains. In addition, the use of NIRS is an attractive method for the prediction of digestibility due to rapid and simple implementation. Therefore it was further tested whether an estimation of precaecal amino acid digestibility using NIRS calibration is possible for each species. The project is closely cross-linked to subprojects 1, 2, 3 and 8.

Subproject leaders

Prof. Dr. Rainer Mosenthin

Prof. Dr. Markus Rodehutscord

Prof. Dr. Hans Schenkel

University of Hohenheim