In vitro assessment of nutritive value of date palm by-products as feed for ruminants

Date-palm leaves, pedicels, date-pits and waste dates are date-palm by-products (DPBP), routinely used as a feed resource by oasis farmers. This work aims to assess in vitro the chemical composition and nutritional value of these DPBP, including waste dates from three varieties (Bouarus, Harchaya and Kentichi). Vetch-oat hay was used as a reference feed material. Palm leaves showed the highest NDF, ADF, lignin and crude protein contents (609, 435, 84, 64 g kg DM, respectively). Cumulative gas production at 144 h of incubation was greatest for Kentichi dates (330 mL gDM) and lowest for date-pits (69 mL gDM). Regardless of the variety, waste dates showed the highest DM effective ruminal degradability (ED=0.48-0.49; estimated for a passage rate of 0.03 h) and organic matter digestibility (OMD), whereas date-pits seemed to be a poorly degradable material, with an ED coefficient of 0.09 g g DM. The lowest total VFA production from ruminal fermentation was with date-pits and the highest with waste dates of the Bouarus variety. These results suggest that waste dates, albeit their low protein content, should be considered highly digestible with energy concentrations as high as that of vetch-oat hay. Palm leaves and pedicels can be considered as highly fibrous emergency roughages for low-producing animals. When DPBP are used as feedstuffs, protein supplements will be necessary to balance the ruminant diets.Peer Reviewe