Comparing Chemical Composition and Digestibility of Pedicels and Palm Leaves as a Source for Livestock Feeding by in vitro and in situ Techniques

The aim of this study was to determine the chemical composition and in vitro digestibility, and to estimate the in vitro fermentation parameters of palm leaves and pedicels from Ghars palm variety. A rumen in situ technique was also used to examine In vitro Digestible Dry Matter (IDDM), In vitro Digestible Crude Protein (IDCP), and In vitro Digestible Neutral Fiber (IDNF), and rate and extent of gas production. Vetch-oat hay was taken as a reference feed material. The samples were collected in Tolga district (southeast Algeria). The Crude Protein (CP) content of the plant species was low for pedicels and palm leaves (33 and 60 g kg−1 DM, respectively). The highest content of total extractable phenols, tannins and condensed tannins was observed in palm leaves whereas pedicels showed lower concentrations. In vitro digestibility and in situ DM disappearance were slightly different for the examined forages. Analogue trends were observed for the in vitro fermentation kinetics estimated from the gas production curves. Pedicels showed the highest DM effective degradability (ED; assuming a passage rate of 0.03 h-1) whereas palm leaves seemed to be a poorly degradable material with an ED coefficient of 0.39 and 0.14 g g-1DM, respectively. Despite the moderate CP and high fiber content along with in vitro digestibility and in situ DM disappearance found in pedicels, in comparison with vetch oat hay degradation, it indicated that this plant could have a greater nutritional value. Dry matter disappearance after 144 h of incubation was negatively correlated with phenolic compounds and total extractable tannins, suggesting that the in vitro techniques can be appropriate for detecting the presence of anti-nutritional substances in shrubs.