Effects of Polyethylene Glycol (PEG) Addition on Chemical Composition, Degradability and Digestibility of White Grape Pomace

The Grape Pomace (GP) is one of the agro-industrial by-products that can be used in ruminant feeding. But it has anti-nutritional factors such as tannins. An experiment was carried out to study the effect of Polyethylene Glycol (PEG) addition on chemical composition, degradability and digestibility of white grape pomace for ruminants. Inclusion rate of PEG to GP was done at 4 levels. The nylon bag technique was used to determine the rate of degradability of DM with 3 rumen-fistulated Azeri buffaloes. Dry Matter and Organic Matter Digestibility (DMD and OMD) were determined using in vitro methods. Results showed that NDF content of WGP increased with PEG inclusion. Crude Protein (CP) concentration of untreated WGP (No PEG) was 13.25% and for WGPI (15.60 g kg(-1) PEG), WGP2 (31.21 g kg(-1) PEG) and WGP3 (46.80g kg(-1) PEG) were 11.41, 10.80 and 10.56%, respectively. TEPH (total extractable phenol) concentration of WGP (No PEG), WGP1 (15.60 g kg(-1) PEG), WGP2 (31.21 g kg(-1) PEG) and WGP3 (46.80g kg(-1) PEG) were 2.36, 1.43, 1.65 and 1.49%, respectively. These observations may show the positive effects of PEG addition to increase degradability value of WGP. According to results of this study it may conclude that inclusion of PEG to WPG can make a progress in degradability and digestibility values and the optimum effect was obtained at WGP2 (31.21 PEG g kg(-1) DM of WPG) inclusion level.