PSXII-5 Feed processing-induced changes in protein molecular structure in relation to nutrient utilization and availability of warm-season Sorghum grain (Sorghum bicolor) in ruminants

Abstract

Abstract The objective of this study was reveal heat related processing (HP) induced changes in protein molecular structure in relation to nutrient utilization and availability of warm-season sorghum grain (Sorghum bicolor) in dairy cows. Three new warm-season genotypes of sorghum grain (Sorghum bicolor) were studied. The nutrient utilization and availability of sorghum grain (Sorghum bicolor) in dairy cows include: protein subfractions, energy values, rumen degradation, and intestinal digestibility of rumen undegraded protein. The protein structure change on molecular level were revealed with cutting edge non-invasive vibrational ATR-FTIR molecular spectroscopy. The warm-season sorghum grains were either maintained in their raw state (as control) or treated with for 80 min at 121°C with the Lindberg/Blue M™. The RCBD data were analyzed using SAS9.4 with Mixed model procedure. Tukey method was used for mean separation. The results showed that compared with the control, the HP treatment altered (P < 0.05) nutrient profiles and utilization and availability in dairy cows and increased (P < 0.05) metabolizable energy and net energy values in dairy cows. The HP treatment also altered (P < 0.05) the protein molecular structure profile of the warm-season sorghum grain. It increased (P < 0.05) the ratio of protein Amide I and Amide II height and decreased (P < 0.05) the ratio of α-helix to β-sheet. In conclusion, the HP treatment altered molecular structure and nutrient profiles without negatively affecting the nutritive value and digestion of warm-season sorghum grain. The molecular spectral profiles revealed by rapid and non-invasive ATR-FTIR molecular spectroscopy could be used as a fast predictor for the warm-season sorghum grain utilization and digestion in dairy cows.