The effects of moisture, lignosulfonate, alcohol and heat treatments on canola meal protein degradation and digestion in ruminants

Abstract

Four experiments were conducted to investigate the methods for protecting canola meal (CM) protein from ruminal degradation. Canola meal was moist heat treated at 110$\sp\circ$C for 60 min. The treated and untreated CMs were used to formulate a treatment and a control diet which were fed to two groups of lambs. The plasma total amino acid (AA) concentration was increased and weight gain efficiency was improved in lambs fed treatment diet compared to control. The CM lignosulfonate (LS), water, alcohol and heat treatments were tested in a 4 x 3 x 2 x 4 factorial design. The increasing LS level increased digestible undegradable intake protein (DUIP) of CM protein by 41% with 6.5% LS added. Three temperature and time levels were not different in improving the DUIP in CM in the presence of 4.0 and 6.5% of LS. Generally addition of water and alcohol did not improve the DUIP in CM. Canola meal was heat treated with or without LS on an industrial scale resulting in four CM treatments, i.e. untreated, or heated to 129$\sp\circ$C with 6.5% LS, 154$\sp\circ$C with or without 6.5% LS, and held for 32 min. These four CM treatments were tested with four cannulated heifers in a 4 x 4 Latin square design. Canola meal heated to 154$\sp\circ$C with LS had a lower in situ effective degradability of protein compared to the control. These four CM treatments were further studied in the same four heifers during their first lactation over four periods in a 4 x 4 Latin square design. The in vivo undegradable intake nitrogen was increased in the diet containing CM heated to 154$\sp\circ$C with LS compared to those obtained with the control diet and the diet containing CM treated to 129$\sp\circ$C with LS. The in vivo apparent digestibility of dietary N and DM in the lower and total GI tract was unaltered by the inclusion of treated CM in the diet. Heating to 154$\sp\circ$C with LS and held for 32 min thus was sufficient to reduce the ruminal degradability without damaging the apparent digestibility of CM protein, and improve the nutritive value of CM to the dairy cows.