Energy concentration and amino acid digestibility in high protein canola meal, conventional canola meal, and in soybean meal fed to growing pigs

Two experiments were conducted to determine digestible energy (DE) and metabolizable energy (ME) and the apparent ileal digestibility (AID) and standardized ileal digestibility (SID) of crude protein and amino acids in high protein canola meal (CM-HP), conventional canola meal (CM-CV), and soybean meal fed to growing pigs. In Exp. 1, 32 barrows (initial body weight: 47.3 ± 6.2 kg) were housed in metabolism cages and randomly allotted to one of four diets with eight replicate pigs per diet. A corn-based diet (973 g/kg corn) and three diets that contained both corn and each of the two sources of canola meal or soybean meal were formulated. Feces and urine were collected for 5 days after a 5-day adaptation period. The DE and ME values were 14.40 and 13.84 MJ/kg in corn, 12.43 and 10.34 MJ/kg in CM-HP, 11.02 and 9.65 MJ/kg in CM-CV, and 15.63 and 14.13 MJ/kg in soybean meal, respectively. The DE and ME were greater (P < 0.05) in corn and soybean meal than in CM-HP and CM-CV, but the DE and ME were not different between CM-HP and CM-CV. In Exp. 2, eight barrows (initial body weight: 46.4 ± 5.6 kg) were equipped with a T-cannula in the distal ileum and randomly allotted to a replicated 4 × 4 Latin square design with 4 diets and 4 periods in each square. A N-free diet and three cornstarch based diets that contained CM-HP, CM-CV, or soybean meal as the sole source of amino acids were formulated. Each period lasted 7 days and ileal digesta were collected on day 6 and 7 of each period. The AID and SID of crude protein and most amino acids in CM-HP and CM-CV were less (P < 0.05) than in soybean meal. The AID and SID of crude protein in CM-HP was greater (P < 0.05) than in CM-CV. However, no differences were observed in AID and SID of any amino acids between CM-HP and CM-CV. The concentration of standardized ileal digestible crude protein and almost all amino acids was greater (P < 0.05) in soybean meal than in CM-HP and CM-CV, and CM-HP contained more (P < 0.05) standardized ileal digestible crude protein and amino acids than CM-CV. In conclusion, increased concentration of crude protein in canola meal does not compromise the concentration of DE and ME, and does not compromise AID or SID of amino acids. As a consequence, the novel CM-HP supplies the same amount of DE and more digestible amino acids for growing pigs compared with CM-CV.