Estimation of the nutritive value of tomato pomace for ruminant using in vitro gas production technique

Abstract

An abundance of agricultural by-products have been used to feed dairy and beef cattle in Iran, in order to reduce the cost of livestock production. The aim of this study was to determine the chemical composition and estimation of nutritive value of dried tomato pomace (DTP) using in vitro gas production technique. Fermentation of DTP samples were carried out with rumen fluid obtained from three mature canulated steers. The samples were collected from "San San Shahd" factory in Urmia, Iran. The amount of gas production for DTP 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 26.4, 50.6, 34.5 and 3.7%, respectively. Gas volume at 24 h incubation (for 200 mg dry samples), soluble fraction (a), insoluble but fermentable fraction (b), potential gas production (a + b) and rate constant of gas production (c) contents were 39.38, -1.05, 52.96, 51.90 and 0.081 ml h^-1, respectively. The organic matter digestibility (OMD), metabolizable energy (ME), short chain fatty acid (SCFA) and net energy for lactation (NEl) contents were 62%, 9.06 MJ kg^-1 DM, 0.0.869 mmol and 4.51 MJ k^g-1 DM, respectively. According to results of this study, it seems that DTP could be used as a valuable food industrial by-product in ruminant nutrition.

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