Nutrient content and in vitro digestibility of Turkish grape pomaces

During harvest of grapes for wine production in Turkey, a total of 28 fresh grape pomace samples from white and red wine grape varieties were collected from wine production facilities. Samples were classified by grape color and the pomace from red grapes was separated manually into stalk, skin plus pulp and seed fractions. Nutrient contents were determined for total samples and for fractions. Assays included dry matter (DM), crude protein (CP), ether extract (EE), neutral detergent fiber (NDF), acid detergent fiber (ADF) and ash. To estimate ruminal digestion, in vitro disappearance of DM and NDF were determined using ruminal fluid collected at a local slaughterhouse. Color of grape altered (P<0.05) DM, CP, NDF and ADF content of the grape pomace. Although in vitro disappearance of DM and NDF at 48 h was similar for pomace from both white and red grapes, DM disappearance was higher at short incubation times for pomace from red grapes. Nutrient content generally differed among the fractions of pomace assayed, and in vitro disappearance of DM at 48 h was higher for skin plus pulp and for seed than for the stalk fraction of the pomace. Fresh grape pomace, particularly pomace from red grapes rich in skin and seed, should be a suitable feed for ruminants and to nonruminants with extensive cecal fermentation.