University of Illinois researchers determined the concentration of true ileal digestible (TID) lysine and relative bioavailable lysine in seven sources of distillers dried grains with solubles (DDGS) when fed to poultry. The TID of amino acids in DDGS were measured using cecectomized roosters and relative bioavailable lysine was measured using standard curve methodology. The seven DDGS sources were analyzed for reactive lysine using the guanidination procedure and Hunterlab L, a, and b scores were measured to determine the degree of lightness, redness, and yellowness in the samples. Results showed that the TID for lysine among the seven DDGS sources varied (P < 0.05) from 52.7 to 70.4%, with an average value of 61.4%. The concentration of relative bioavailable lysine did not differ among the seven sources of DDGS. The average concentration of TID lysine in DDGS was not different from the concentration of bioavailable lysine (0.47% and 0.53%, respectively). The concentration of TID lysine was correlated (r2=0.84, P < 0.05) with the concentration of reactive lysine in the samples. Hunterlab L scores of DDGS were correlated (r2=0.90, P <0.05) with the concentration of bioavailable lysine. In conclusion, the concentration of TID lysine in DDGS is close to the concentration of bioavailable lysine for chicks. The researchers concluded that values for reactive lysine and Hunterlab L may be used to estimate the concentration of TID lysine and bioavailable lysine in DDGS, respectively.

Pahm, A. A. and co-workers. 2008. True ileal amino acid digestibility in cecectomized roosters and lysine bioavailability in chicks fed distillers dried grains with solubles. J. Anim. Sci. 86:180/J. Dairy Sci. 91:180 (Abstract 210).

The Chemical Composition of Soybean Hulls
The objective of this study was to examine the variation in chemical composition of soybean hulls. The goal was to develop regression equations characterizing the nutritive value of soybean hulls for use in swine diets. Soybean hull samples were collected from different processing plants across the U.S. and analyzed for crude protein (CP), gross energy (GE), crude fiber (CF), acid detergent fiber (ADF), neutral detergent fiber (NDF), fat, ash, calcium (Ca) and phosphorus (P). Thirty-eight samples were used to determine maximum, minimum, and mean values on a dry matter (DM) basis. Regression equations among the nutrients also were established. A high correlation was observed between CF and CP, with the CF predicting 94.7% of the variation in CP content (Y = -1.160x + 55.49; R2 = 0.95). Crude fiber also was highly correlated to ADF (Y = 1.256x + 0.612; R2 = 0.96); NDF (Y = 1.657x + 2.234; R2 = 0.97); and estimated DE (Y = -90.86x + 4819; R2 = 0.94). A high correlation was also observed between CP and estimated DE (Y = 74.79x + 521.9; R2 = 0.90). In summary, the chemical composition of soybean hulls can be highly variable; however, CF content can help explain much of the variation in CP, ADF, NDF, and estimated DE.
Nutritional Values of Soybean Hulls on a DM Basis
Barbosa, F.F. and co-workers. 2008. Variation in chemical composition of soybean hulls. J. Anim. Sci. 86:573/J. Dairy Sci. 91:573 (Abstract 697).