Novel Techniques for the Extraction of Rumen Un-Degradable Amino Acids from Distiller’s Coproducts

Providing adequate and balanced amino acid supply increases nitrogen capture from animal feed into human food products, creating greater food security while lowering environmental impact. New processing techniques allow the extraction of specific protein (SP) from distiller’s dried grains and solubles (DDGs) resulting in greater rumen un-degradable amino acid (RUAA) supply. The degradation rate and residual RUAA content of two SP extracted from corn (cDDGS) were compared with cDDGS, soya bean meal (SBM) and RUAA processed from SBM and RSM. A Cornell model was applied to thirty-three dried and ground (1 mm) samples of; cDDGS, SBM, RUAA SBM, RUAA RSM, and two SPs (SP2 and SP50), that were combined with a partial mixed ration (PMR), buffered, flushed with CO₂ and incubated for 16 h at 39^oC to measure in vitro gas production (IVGP) using Ankom-RFS. Feed composition was analysed pre and post incubation and RUAA profile was estimated using gas liquid chromatography. Data was analysed using general linear modeling, applying feed as a fixed effect and all other factors as random effects, using a confidence interval of 0.95 and differences using Tukey’s test (P value <0.05). Gas production was highest from cDDGS and lowest from Hiprosoya, but similar in RUAA from SBM and RSM, SP2 and SP50. RUAA was greatest from SBM, but similar from Hiprosoya, SP2 and SP50 and lowest from RUAA RSM. Liquor pH did not differ. SP50 had the highest total VFA and lowest A:P ratio, while SP2 was similar to RUAA from SBM and/or RSM. In conclusion, results demonstrated the potential of SP2 and SP50 to increase the RUPAA from cDDGS to similar amounts provided by RUAA SBM.