Distillers Dried Grains with Solubles as a Protein Source for the Chick

Abstract

Five trials were conducted to evaluate the protein quality of distillers dried grains with solubles (DDGS) for growing chickens. The DDGS was found to contain 28.6% crude protein (CP) and .72% lysine. When fed as the sole source of dietary protein, tryptophan and arginine were the second- and third-limiting amino acids, respectively, after lysine, which was first-limiting. Arginine, however, was almost as limiting as tryptophan in the protein of DDGS.The protein quality of DDGS was compared to dehulled soybean meal (SBM) in two chick bioassays. When fed as the sole source of dietary protein (6% CP), chicks gained faster and more efficiently when fed SBM than when fed DDGS. However, when DDGS was supplemented with lysine, weight gains, protein efficiency ratios, and net protein ratios were similar to those obtained with SBM. In a corn-SBM diet (24% CP), at least 20% of the SBM could be replaced by DDGS without affecting growth rate. With lysine supplementation, up to 40% of the SBM could be replaced by DDGS with little depression in growth rate. Two additional trials evaluated the availability of lysine in DDGS using both the chick growth assay procedure and the total fecal collection method. The growth assay produced a value of .476% bioavailable lysine, which yielded an availability estimate of 66.1% when expressed as a percent of the total lysine content of DDGS. The total fecal collection assay using adult roosters yielded a true digestibility estimate of 82.4% for the lysine in DDGS.