Abstract

This study was carried out to determine the effects of xylose and moisture heating treatments (0, 5 and 10 g/kg DM) of soybean meal (SBM) on in situ rumen degradability characteristics in cow and its proteins sub-units fractions by a SDS-PAGE discontinues system. In the experiments, three ruminally cannulated male Taleshi cow were used to measure in situ rumen degradability characteristics of dry matter (DM) and crude protein (CP) of different treated SBM samples. SBM were treated with xylose (5 and 10 g/kg DM) and moisture heating. Xylose and moisture heated treatment significantly (P<0.05) reduced degradability values of DM and CP for SBM. Rumen effec-tive protein degradability values of SBM (k = 0.02, 0.05 and 0.08 h^-1) were significantly decreased by all treatments (P<0.05). Effective degradability of DM (k = 0.05 h^-1) were 65.17, 64.90, 61.77 and 58.50 g/kg and CP was 63.77, 61.97, 60.83 and 60.23 g/kg for NTSBM (non treated SBM), TSBM (SBM + 30 min moisture heating treated), TSBM 5 g/kg (SBM + 30 min moisture heating treated + 5 g/kg xylose) and TSBM 10 g/kg (SBM + 30 min moisture heating treated + 10 g/kg xylose) treatments, respectively. Treatment of SBM with 5 and 10 g/kg of DM caused a reduction in the dry matter and effective crude protein degradability compared with NTSBM. Electrophoretic patterns of untreated and treated SBM protein residues revealed that β-conglycinin β, α and ά subunit were degraded completely within 4h of incubation in the rumen, whereas the  acidic and basic subunits of glycinin were degraded after 48h incubation in treated SBM with Xylose. It is concluded that SBM proteins can be effectively protected from degradation in the rumen by xylose and moisture heating treatment.

Key words: Soybean meal, degradability, xylose, moisture heat, SDS-PAGE.