Comparing the Effect of Ionizing Radiations of Electron Beam and Gamma Ray on Ruminal Degradation Kinetics of Soybean Meal Protein and Amino acids

This research was conducted to compare effects of electron beam (EB) and gamma ray (GR) treatments at doses of 25, 50 and 75 kGy on soybean meal (SBM) ruminal degradation kinetics of crude protein (CP) and amino acids (AA). The nylon bag and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) techniques were used for this aim. Ionizing radiations decreased washout and degradation rate fractions and increased potentially degradable fraction of CP. GR had more effects on degradability parameters of CP than the EB. Irradiation processing caused decreasing in AA degradation after 16 h of ruminal incubation significantly. GR irradiation was more effective than EB irradiation in lessening the ruminal degradability of AA. In unirradiated SBM, subunits ά, α and β of β-conglycinin protein disappeared after 4 h, and basic and acidic subunits of glycinin protein disappeared after 16 h of rumen incubation. The 50 and 75 kGy doses of EB and GR maintained and preserved the subunits of β-conglycinin until 16 h and 48 h for glycinin subunits. The results of this study showed greater effects of GR than the EB in reducing the ruminal degradation of CP and AA, while the ruminal disappearance of the protein subunits in the SBM was equally affected by these ionizing radiations.