Nutritional characteristics of by-products originating from the Central European ethanol fuel industry for pigs1

Abstract

Chemical composition and nutrient and energy digestibilities were determined in 4 samples of dried distillers grains with solubles (DDGS) and 1 sample of wet distillers grains (WDG) from 4 ethanol fuel manufacturers. The cereal sources used for ethanol production were wheat (Triticum aestivum; 1 sample), wheat + barley (Hordeum vulgare; 2 samples), and maize (Zea mays; 2 samples). The nutrient contents (expressed as % of DM) were variable, ranging from 30.5 to 39.5 CP, 4.4 to 12.3 fat, 7.5 to 12.9 crude fiber, 2.7 to 7.8 ash, and 0.4 to 0.9 total P. The concentration of Lys ranged from 2.05 to 5.20 g/kg DM. The diets were fed to 6 gilts (39.9 ± 1.9 kg BW) fitted with ileal T-cannulas using a 5 × 6 Youden square. Each experimental period comprised a 5-d adaptation followed by a 2-d collection of urine and feces and 1-d (24 h) collection of ileal digesta. Using acid-insoluble ash as a marker, apparent ileal digestibility (AID) and apparent total tract digestibility (ATTD) of nutrients and energy and AID of AA were calculated. The ATTD of N ranged from 55.7 to 83.7%. The N retention expressed as percentage of N intake ranged from 10.2 to 32.0. Except for wheat-based DDGS, the AID of N was 66.8%. The ATTD and AID values of NDF were 52.8 and 24.4%, respectively. The concentration of total P in WDG was half of values in DDGS, which likely caused its very low ATTD (1.4%). The ATTD and AID of energy ranged from 58.8 to 73.9% and from 40.6 to 54.1%, respectively. The AID of AA was greatest (P < 0.001) in WDG (71.8%) and lowest (P < 0.001) in DDGS from wheat (44.8%). In conclusion, nutrient variability among DDGS samples varies greatly, and source of origin is an important determinant of quality.