Prediction of forage ad libitum intake and in vivo digestibility by near infrared spectroscopy

Cilj ovog rada je prikazati stanje spektroskopije u bliskom infracrvenom području (NIR spektroskopije) kao tehnologije za procjenu ad libitum konzumacije suhe tvari (ST) i organske tvari (OT) te in vivo probavljivosti ST, OT i OT u ST (Dvrijednosti) voluminozne krme. U usporedbi s provedbom skupih, radno zahtjevnih i dugotrajnih bioloških istraživanja radi utvrđivanja ad libitum konzumacije i in vivo probavljivosti voluminozne krme, NIR spektroskopija je brza, fizikalna, nedestruktivna, multianalitička i eklološki prihvatljiva metoda koja može dati precizne i točne rezultate uz minimalnu ili nikakvu pripremu uzoraka. Biološki se parametri teže procjenjuju NIR spektroskopijom u odnosu na kemijske parametre voluminozne krme radi varijacija između životinja, a posljedično pogrešaka u procjeni reakcija životinja na određenu hranidbu i hranu te činjenice da se niti jedan biološki parametar ne može utvrditi u kemijskom laboratoriju s visokom razinom točnosti. Prikazani kalibracijski modeli su prihvatljive razine pouzdanosti procjene ad libitum konzumacije i in vivo probavljivosti voluminozne krme prema utvrđenim koeficijentima determinacije (R2) (0,7-0,9 i 0,47-0,98 slijedom), standardnim greškama kalibracije (SEC) (4,28-6,89 i 0,01-1,69 slijedom), standardnim greškama unakrsne validacije (SECV) (4,53-7,92 i 0,02-2,15 slijedom) te standardnim greškama procjene (SEP) (5,42-9,59 i 0,026-5,7 slijedom). Ovo istraživanje potvrđuje potencijal NIR spektroskopije za procjenu ad libitum konzumacije ST i OT voluminozne krme i in vivo probavljivosti ST, OT i D-vrijednosti voluminozne krme.The objective of this paper is to present the potential of near-infrared spectroscopy (NIR spectroscopy) as a technology for predicting ad libitum intake of dry matter (DM) and organic matter (OM) as well as in vivo digestibility of DM, OM and OM in DM (D-value) in forage. Compared to the expensive, labor-intensive and time-consuming biological research methods for determining forage ad libitum intake and in vivo digestibility, NIR spectroscopy is a fast, physical, non-destructive, multianalytic and ecologically acceptable method that can provide precise and accurate results with minimal or no sample preparation. Forage biological parameters are more difficult to predict by NIR spectroscopy than chemical parameters due to variations among animals, consequent errors in animal reactions to certain feeds and food and the fact that no biological parameter can be determined in a chemical laboratory with high accuracy level. The calibration models presented are at acceptable levels of reliability for the prediction of forage ad libitum intake and in vivo digestibility according to the determined coefficients of determination (R2) (0.7-0.9 and 0.47-0.98 respectively), standard errors of calibration (SEC) (4.28-6.89 and 0.01-1.69, respectively), standard errors of cross-validation (SECV) (4.53-7.92 and 0.02-2.15, respectively) and standard errors of prediction (SEP) (5.42-9.59 and 0.026-5.7, respectively). This study confirms the high potential of NIR spectroscopy to predict the ad libitum intake of DM and OM and the in vivo digestibility of DM, OM and D-values in forage