Evaluation of prediction of barley digestible nutrient content with near-infrared reflectance spectroscopy (NIRS)

Near-infrared reflectance spectroscopy (NIRS) was evaluated as a tool to predict the contents (ileal digestible) of protein (IDP), lysine (IDLys), cystine (IDCys), methionine (IDMet) and the contents (faecal digestible) of organic (DOM) and dry matter (DDM) in barley samples for pig diets. Twenty barley samples, which had previously been tested for in vivo and in vitro nutrient digestibility in pigs, were scanned. A number of NIRS calibrations were developed using the in vitro digestibility data of fifteen barley samples as a reference. Validation using the five remaining barley samples was used to select the best equations. The robustness of the calibrations was further tested by validating them with the in vivo digestibility data. Despite the limited number of samples used in the calibration, NIRS was able to accurately predict the content of IDP, IDLys, IDMet and DOM. On the other hand, DDM and IDCys contents could not be accurately predicted. Although, larger sample sets will be required to generate calibrations, which could be applied in the feed industry, these results show that NIRS is a potentially good tool to evaluate the digestible nutrient content of barley.