Abstract

The aim of this study was to determine the chemical composition and estimation of nutritive value of white grape pomace (WGP) using in vitro gas production technique. Fermentation of WGP samples were carried out with rumen fluids obtained from three mature cannulated steers. The samples were collected from a factory in Urmia, Iran. The amount of gas production for WGP at 2, 4, 6, 8, 12, 24, 48, 72 and 96 h were measured. The results showed that the crude protein (CP), neutral detergent fiber (NDF), acid detergent fiber (ADF) and non-fibrous carbohydrate (NFC) contents were 17.27, 59.5, 52.5 and 13.5%, respectively. Gas production at 24 h and potential gas production (a + b) were 30.92 and 79.89 ml, respectively. The organic matter digestibility (OMD), metabolizable energy (ME) and short chain fatty acid (SCFA) contents were 50.50%, 7.4 MJ kg^-1 DM and 0.69 mmol, respectively. The net energy for lactation (NEL) content was 3.31 MJ kg^-1DM. According to the results of this study, it seems that WGP could be used as a valuable food industrial by-product in ruminant nutrition.

Key words: Nutritive value, gas production, grape pomace, short chain fatty acid, metabolizable energy.