Research on crude protein and digestibility of Arnica montana L. using conventional NIR spectrometry and hyperspectral imaging NIR.

摘要

Arnica montana L. (AM) is considered a medicinal plant, used as hay in feed ration. The aim of this study is to assess the prediction of protein content and in vitro organic matter digestibility value in grass mixtures containing Arnica montana L., and in a second step to check if these values have a positive or negative influence in the mixtures. Crude protein has been selected because it is one of the most important quality parameters of forages as nutritional element used in animal feeding. The protein is required on a daily basis for maintenance, lactation, growth and reproduction, but is important for agriculture too, because a high content of protein makes it an important source of feed. The digestibility is also important, because it refers to the extent to which a feedstuff is absorbed in the animal body as it passes through an animal's digestive tract. In this study, the Weende system (the Kjeldahl method) for the protein content, together with the enzymatic technique for digestibility, was applied and used in combination with non-destructive methods, like those based on the Near Infrared Spectroscopy (NIRS) or the Near Infrared Hyperspectral Imaging. Based on NIR imaging system data, the PLS-DA was used to discriminate between the classes with AM and classes without AM, as well as to build a model that could be used to predict the composition of mixtures. More than 99% correct prediction for AM was obtained. The crude protein content of the hay determined by classical method decrease from the type of meadow Agrostis capillaris L. - Festuca rubra L. (15.22%) until to the pure sample of Arnica montana L. (11.19%); however, the digestibility was highest in the pure sample of Arnica montana L. (84.13%) and lowest in samples from the type of meadow Agrostis capillaris L. - Festuca rubra L. (57.18%) or in samples with the participation of Arnica montana L. This study should lead to a more important point, which is to verify whether the medicinal properties of Arnica montana L. can be transferred or not to milk production through the dairy cow feed.