Determination of nutritive value of leaves of several Vitis vinifera varieties as a source of alternative feedstuff for sheep using in vitro and in situ measurements

The nutritive values of leaves from four varieties of Vitis vinifera, Kabarcık, Mahrabası, Kıbrıs and Ak were evaluated based on their chemical composition, in vitro gas production, dry matter (DM) and crude protein (CP) degradation. CP contents of vine leaves ranged from 9.94 to 12.14%, with Kabarcık showing the highest CP content. Neutral detergent fiber (NDF) and acid detergent fiber (ADF) contents of vine leaves ranged from 28.46 to 38.43 and 18.83 to 28.35%, respectively. Condensed tannin (CT) ranged from 6.41 to 10.58%. The rank order in terms of gas production, DM and CP degradation was as follows: Kabarcık > Mahrabası = Kıbrıs = Ak. Cell wall contents (NDF and ADF) and CT contents of vine leaves were negatively correlated with gas production, DM and CP degradation.Leaves from Kabarcık with a considerable amount of CP had a higher rank value in terms of gas production, DM and CP degradation. Thus leaves of Kabarcık may have a higher potential nutritive value for sheep in terms of rumen and whole tract digestion.