Effects of protein concentration and heat treatment on concentration of digestible and metabolizable energy and on amino acid digestibility in four sources of canola meal fed to growing pigs.

Two experiments were conducted to determine DE and ME and the apparent ileal digestibility (AID) and the standardized ileal digestibility (SID) of CP and AA in 4 sources of canola meal (high-protein [CM-HP], high-temperature-processed [CM-HT], low-temperature-processed [CM-LT], and conventional [CM-CV] canola meal) and in conventional soybean meal (SBM) fed to growing pigs. In Exp. 1, 48 growing barrows (initial BW: 39.7 ± 1.58 kg) were individually housed in metabolism cages and randomly assigned to 6 treatments in a randomized complete block design with 2 blocks of 24 pigs and 8 replicate pigs per treatment. The 6 diets included a corn-based basal diet and 5 diets that were formulated by mixing corn and 1 of the sources of canola meal (39.0% inclusion) or SBM (28.5% inclusion). Feces and urine were collected for 5 d following a 5-d adaptation period. The DE and ME in each source of canola meal and in SBM were calculated using the difference procedure. The DE and ME in the 4 sources of canola meal were less (P < 0.05) than in corn and SBM (DE: 2,854, 2,680, 2,892, and 2,883 vs. 3,324 and 3,784 kcal/kg, respectively; ME: 2,540, 2,251, 2,681, and 2,637 vs. 3,213 and 3,523 kcal/kg, respectively). No differences in the concentrations of DE and ME were observed among the 4 sources of canola meal. In Exp. 2, 12 growing barrows (initial BW: 34.0 ± 1.41 kg) that had a T-cannula installed in the distal ileum were randomly allotted to a repeated 6 × 6 Latin square design with 6 diets and 6 periods in each square. Five diets that contained 35% SBM or 45% of 1 of the 4 sources of canola meal as the sole source of CP and AA were formulated, and a N-free diet was also used. Each period lasted 7 d and ileal digesta were collected on d 6 and 7 of each period. The AID and SID of CP and all AA in SBM were greater (P < 0.05) than in the 4 sources of canola meal. Compared with CM-CV, CM-HP had greater (P < 0.05) AID of Ile, Lys, Asp, Cys, and Pro and greater (P < 0.05) SID of Lys and Cys. However, no differences between CM-HT and CM-LT were observed. In conclusion, regardless of the concentration of CP and the processing used, canola meal provides less DE and ME to pigs than corn and SBM, and the SID of AA in canola meal is less than in SBM. The processing temperature used in this experiment did not affect DE and ME or SID of AA in canola meal. The SID of Lys and Cys was greater in CM-HP than in CM-CV.