Effect of Polyethylene Glycol (PEG) on in vitro Gas Production, Metobolizable Energy and Organic Matter Digestibility of Apple Tree Leaves as Ruminant Feed1

This study was carried out to determine the chemical composition and to estimate the metabolizable energy and digestible organic matter of apple tree leaves as ruminant feed, after addition with polyethylene glycol (PEG). Experimental materials from different parts of Eastern Azerbaijan province (northwestern Iran) were collected. After drying the samples and provide uniform mix, chemical composition including dry matter (DM), crude protein (CP), ether extract (EE), crude ash (CA), cell wall (NDF) and cell wall without hemicellulose (ADF) were estimated as 92.53, 10.80, 9, 8.60, 23 and 15.4 %, respectively. Gas production test with mixtures of filtered liquid of two Taleshi native male cattle rumen after 2, 4, 6, 8, 12, 24, 48, 72 and 96 hours was performed. The amount of gas produced after 24 and 96 hours incubation, was equivalent to 52.44 and 62.60 ml per 200 mg diy matter of sample, respectively. The digestibility of organic matter was 74.96% and the metabolizable energy was 11.48 (MjKg-1). Because of tannins content of experimental samples, we added PEG with 2:1 ratio (400 mg PEG: 200 mg sample) into gas test syringes, for evaluation of PEG effects. The PEG supplementation had also a significant (p<0.05) increase in the estimated parameters of gas production, OMD and ME of samples. Based on the obtained results it is concluded that the apple tree leaves has relatively good nutritional value for ruminant nutrition.