Effect of extrusion with molasses on the rumen undegradable protein fraction of canola oilcake meal and sweet lupins

Abstract

The effect of the extrusion of canola oilcake meal (COM) and crushed sweet lupins (CSL) with molasses on the dry matter (DM) and crude protein (CP) degradability was determined in situ. Locally sourced (SOILL Moorreesburg, South Africa) COM and CSL, with the addition of 6% molasses, were extruded at a maximum temperature of 116 °C. A total of six Dohne Merino wethers (± 80 kg), fitted with rumen cannula, were used in this trial. Samples in polyester bags (5 g) were incubated in the rumen of the sheep at intervals of 0, 2, 4, 8, 16, 24, and 48 h. The DM and CP disappearances from the rumen were determined and degradability parameters were estimated. Extrusion increased the potentially degradable CP fraction by 43.5%. At each outflow rate, the average CP effective degradability of COM (68.2%) was lower than that of CSL (78.0%). Extrusion substantially lowered the CP effective degradability for both protein sources at every outflow rate tested. The biggest effect was seen at 0.08/h, where effective degradation was lowered by 25.6%. Extrusion with molasses was found to modify ruminal degradation parameters of both canola oilcake meal and crushed sweet lupins, while also decreasing the effective rumen degradation, especially at faster outflow rates. Thereby, the rumen undegradable protein fraction was increased by 85.4%. This study shows that COM and CSL extruded with 6% molasses can substantially increase RUP.

Effect of Tannin Inclusion on the Enhancement of Rumen Undegradable Protein of Different Protein Sources

“…Although widely utilized, a significant portion of these feeds' protein is fermented in the rumen [8,9]. Thus, researchers have sought processing techniques (physical and chemical) to enhance protein protection against ruminal fermentation and improve protein utilization [10]. Several processing methods have been developed to manipulate the ruminal degradation of protein sources with the objective to increase feedstuff RUP, including autoclaving [11], microwave treatment [12,13], toasting or irradiation [14], heating [15,16], malic acid [16], xylose [17], and tannins [18,19].…”