Comparison of the nutritive value and fatty acid profile of the green pruning residues of six grapevine (Vitis vinifera L.) cultivars

Interest in the green pruning residues of grapevine (GPR), harvested in spring, as a feedstuff has been increasing due to its nutritive value. The aim of this study was to investigate the differences between six cultivars of red Vitis vinifera (Nebbiolo, Barbera, Syrah, Grenache, Pinot Noir and Cabernet Sauvignon) as far as the chemical composition, gross energy, in vitro apparent digestibility (DMD) and fatty acid (FA) profile of their GPR are concerned. There are not significant differences among cultivars in terms of dry matter (DM), crude protein and lipid contents. Whereas there are significant differences among cultivars in terms of ash, neutral detergent fibre (NDF), acid detergent fibre (ADF) and lignin contents ranged from 54 to 70, 495 to 542, 375 to 425, and 91 to 142 g/kg DM, respectively. Moreover, the cell wall contents (NDF, ADF and lignin) of the GPR were negatively correlated to the DMD, which ranged from 449 to 544 g/kg DM. The FA profile of the GPR was characterized by a low content of saturated FAs and a high content of polyunsaturated FAs (PUFA); among the latter, α-linolenic acid and linoleic acid ranged from 356 to 419 and 228 to 312 g/kg of the total FAs, respectively. Linoleic acid was found to differ significantly for the six cultivars, and the highest value was found in the GPR of the Pinot Noir. Thus, GPR may have a good potential nutritive value and an interesting PUFA content for small ruminants.