Lignocellulosic materials characterization of wild and cultivated cardoon

Cardoon (Cynara cardunculus L.) is a perennial crop. The first productive cycle begins with seed germination, usually at the beginning of autumn. After the cotyledons emergence, leaves start to develop forming a rosette. At the end of spring appears the floral scape, which ends in several heads. After flowering and pollination, the fruits (achenes) are formed and the aerial biomass dries. This biomass could be used for multiple purposes such as obtaining biofuels, paper pulp production and fodder. The main objective of this work was to characterize the lignocellulosic material from cardoons obtained after seed harvest and determine its potential use as forage for animal feed. The aboveground biomass was collected at the end of the productive cycle from 10 plants per accession (six wild and six cultivated cardoon) and they were submitted to chemical analyses. Energetics parameters as heating values (HV), in vitro digestibility (IVD%), theoretical digestibility (DE) and metabolizable energy (EM) were evaluated. Significant differences were observed for chemical composition between accessions but not between botanical varieties. No significant differences were found neither between accessions nor botanical varieties for digestibility (5.66 MJ kg^-1) and metabolizable energy (4.64 MJ kg^-1). Cardoon chemical composition was compared with dry biomass from different species used as fodder. These results showed that the C. cardunculus L. lignocellulosic biomass could be used for animal feed, nevertheless its low protein content reduces its quality. However, this issue could be improved adding a supplement rich in protein. Considering that cardoon seeds have 25% of oil and 20% of protein, the press cake obtained after oil extraction could be used as supplement for a good quality fodder, increasing the profitability of the culture.