Amino acid digestibility and energy concentration of high-protein corn dried distillers grains and high-protein sorghum dried distillers grains with solubles for swine

Abstract

A study was conducted to determine the AA digestibility and energy concentration of a specialized high-protein corn distillers dried grains (HPC-DDG) product and a high-protein sorghum dried distillers grains with solubles (HPS-DDGS) product. Six growing barrows (BW = 22.7 kg) were surgically fitted with T-cannulas at the terminal ileum and allotted randomly to 3 treatments in a crossover design with 3 periods. The treatment diets were 1) 67% HPC-DDG and 2) 50% HPS-DDGS as the sole protein sources, and 3) an N-free diet for determining basal endogenous AA loss. All diets contained 0.25% chromic oxide as an inert marker. Digesta and fecal samples were collected and analyzed for AA and energy concentrations. After chemical analysis, standardized and apparent ileal digestible (SID and AID, respectively) AA and GE were determined for each coproduct. The DE, ME, and NE values for HPC-DDG and HPS-DDGS also were calculated. The chemical composition of HPC-DDG and HPS-DDGS on a DM basis was 40.8% CP, 5.4% fat, 22.9% ADF, 36.6% NDF, 0.04% Ca, and 0.42% P and 48.2% CP, 3.1% fat, 17.5% ADF, 20.4% NDF, 0.13% Ca, and 0.82% P, respectively. The DM content of HPC-DDG and HPS-DDGS was 89.50 and 91.88%, respectively. Analyzed AA content of HPC-DDG was greater than that of traditional corn DDGS. The Lys content of HPC-DDG was 1.36% (DM basis), resulting in a Lys-to-CP ratio of 3.2%. In HPS-DDGS, most AA were present in greater proportions than in HPC-DDG or conventional sorghum DDGS. The HPS-DDGS Lys content was 1.7% (DM basis), equivalent to a Lys-to-CP ratio of 3.5%. In HPC-DDG, the AID for Lys, Met, Thr, and Trp were 65.9 ± 1.7, 87.0 ± 1.9, 72.8 ± 3.4, and 76.2% ± 3.5, respectively, and SID values were 67.8 ± 1.7, 87.5 ± 1.9, 75.0 ± 3.5, and 78.6 ± 3.7%, respectively. For HPS-DDGS, the AID for Lys, Met, Thr, and Trp were 51.9 ± 5.3, 73.0 ± 3.1, 60.6 ± 5.3, and 71.7 ± 3.4%, respectively, and SID values were 53.7 ± 4.9, 73.8 ± 3.0, 63.0 ± 4.9, and 73.8 ± 3.0%, respectively. The GE, DE, and calculated ME and NE values were 5,293, 3,703 ± 121, 3,426 ± 121, and 2,131 ± 88 kcal/kg of DM, respectively, for HPC-DDG and 5,108, 3,878, 3,549, and 2,256 kcal/kg of DM, respectively, for HPS-DDGS. Results indicate that both coproducts are well suited for use in swine diets and that actual AA digestibility values and calculated energy concentrations can now be used in swine diet formulation.