Chemical characterization and in situ nutrient degradability of wet distillers' grains derived from barley-based ethanol production

A study was conducted to characterize the carbohydrate and protein fraction s of barley-based distillers grains (BDG) derived from a mix of 70% barley, 20% wheat and 10% rye/triticale. Amino acid composition, ruminal escape pr otein and amino acid values, and ruminal nutrient degradability of BDG were determined relative to wheat-based distillers';:rains (WDG) derived from 1 00% wheat. On a dry matter (DM) basis, BDG contained 743 g kg(-1) neutral ( NDF) and 311 g kg(-1) acid (ADF) detergent fibre, and 154 g kg(-1) crude pr otein (CP). More than 50% of BDC. protein was associated with NDF while 17% was associated with ADE Glutamic acid was the most abundant amino acid in both distillers grains and was lower (p < 0.05) in BDG (184 g kg(-1) of ami no acids) than WDG (243 g kg(-1) of amino acids). The concentration of lysi ne was higher (p < 0.05) in BDG than in WDG while that of methionine was si milar in both byproducts. Ruminal escape protein value was greater (p < 0.0 5) for BDG than for WDG. However., the ruminal escape values for most of th e amino acids were not different between BDG and WDG. Ruminal degradability of NDF from WDG (454 g kg(-1) of NDF) was higher (p < 0.05) than that from BDG (360 g kg(-1) NDF). The results of this study showed that fibre and pr otein fractions of BDG are less degradable in the ruminal than the correspo nding fraction from WDG. However, data of amino acid composition and rumina l undegradability suggest that the quality of amino acids of BDG reaching t he small intestine of ruminants is equal or better than that from WDG. (C) 2000 Elsevier Science B.V. All rights reserved.