This study was carried out to determine the chemical composition and estimation of nutritive value of apple pomace (AP) by-product using in vitro gas production technique. Fermentation of AP samples were carried out with rumen fluid obtained from three mature canulated steers. The samples were collected from SanSan Shahd factory in Urmia, Iran. The amount of gas production for AP at 2, 4, 6, 8, 12, 24, 48, 72 and 96 hours were measured. The results showed that the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF), ether extract (EE), ash and non-fibrous carbohydrate (NFC) contents were 90.2, 612, 467, 37, 23 and 237.8 g/kg DM, respectively. Gas volume at 24 h incubation (for 200 mg dry sample), soluble fraction (a), insoluble but fermentable fraction (b), potential gas production (a + b) and rate constant of gas production (c) contents were 58.92, 0.9095, 76.91 and 77.82 ml/200mg DM and 0.0574 ml/h, respectively. Calculated amounts of OMD, ME, SCFA and NEl were 714.6 g/kg DM, 10.73 MJ/kg DM, 1.304 mmol and 6.504 MJ/kg DM, respectively. According to results of this study it seems that AP could be used as a valuable by-product in ruminant nutrition.
