Energy and amino acid utilization in expeller-extracted canola meal fed to growing pigs

Two experiments were conducted to determine the nutritive value of expeller-extracted canola meal (EECM) for growing pigs. In Exp. 1, a total of 6 ileally cannulated barrows (average initial BW = 26.8 kg) were fed 3 diets in a replicated 3 x 3 Latin square design to determine the apparent and standardized ileal digestibility (SID) values of N and AA and the SID AA contents of EECM. The 3 diets were a cornstarch-based diet with either solvent-extracted canola meal (SECM) or EECM as the sole source of protein, and a low-casein cornstarch-based diet, which was used to estimate basal endogenous N and AA losses to determine the SID of N and AA. All 3 diets contained chromic oxide as an indigestible marker for determining nutrient digestibility by the indicator method. In Exp. 2, a total of 18 intact barrows (average initial BW = 25.9 kg) were fed 3 diets in a completely randomized design (6 pigs per diet) to determine apparent total tract digestibility and retention of nutrients and the DE and ME contents of EECM. The diets were a basal corn-based diet or the basal diet with corn replaced by 35% SECM or EECM. The basal diet was used for determining the total tract digestible nutrient content by the difference method. Solvent-extracted canola meal, which is commonly used in the formulation of swine diets, was fed in both experiments for comparison with EECM. The SECM and EECM were similar in CP content (41.8 vs. 41.4%). Expeller-extracted canola meal was, however, greater in ether extract content (12.03 vs. 5.54%) and decreased in NDF content (23.8 vs. 29.9%) compared with SECM. The EECM also had a greater content of all the AA except Met, Cys, and Ser, by approximately 6.6%; Cys was greater in SECM, whereas Met and Ser were similar between the 2 meals. The EECM had greater (P < 0.05) SID of N, Arg, Ile, Leu, Phe, Glu, and Pro. The SID contents of Arg, His, Ile, Leu, Phe, Val, Ala, Asp, Glu, Gly, Pro, and Tyr were also greater (P < 0.05) for EECM than for SECM by an average of 15%. The EECM had greater (P < 0.01) DE (4,107 vs. 3,790 kcal/kg) and ME (3,978 vs. 3,564 kcal/kg) values compared with SECM. The results show that the EECM used in the current study had greater digestible AA and energy and a greater ME content than the SECM; hence, it may be a better source of protein and energy for growing pigs than SECM.