Characterizing the Nutritional Value of Feed through Innovative Methods of Measuring Digestibility for Sustainable Poultry

The DigSPIR project aimed to simplify and extend the assessment of feed digestibility in poultry by using near infrared spectroscopy (NIRS). An initial spectral database was built from feed and excreta samples collected between 1997 and 2011 alongside reference digestibility values. Five additional digestibility trials covering various feeds, nutritional levels, bird ages and enzyme additions expanded the spectral library and improved calibration models. Predictions for excreta composition, especially gross energy, starch and nitrogen, correlated strongly with reference analyses. Combining feed and excreta spectra yielded an energy digestibility prediction with R²=0.94 and a 56 kcal/kg DM error (<2% of feed energy). On-farm trials confirmed the method’s consistency, supporting further calibration with farm-level data.