The nutritional value of expeller-pressed canola meal for grower-finisher pigs

Expeller-pressed (EP) canola meal contains more residual oil than solvent-extracted canola meal and might be an attractive feedstuff for swine, but it has been poorly characterized. In Exp. 1, six ileal-cannulated barrows (36 kg of BW) were fed at 3x maintenance either a 44% EP canola meal diet or a N-free diet in a crossover design to measure energy and AA digestibility and calculate standardized ileal digestible (SID) AA and NE content, with 6 observations per diet. Each period consisted of a 5-d diet adaptation and a 2-d feces and 3-d digesta collection. The EP canola meal contained (% of DM) 38.5% CP, 13.3% ether extract, 2.42% Lys, 1.54% Thr, 0.62% Met, and 23.2 mu mol/g of glucosinolates. Apparent total tract energy digestibility was 75.0% and the DE and predicted NE content were 3.77 and 2.55 Mcal/kg (in DM), respectively. The SID AA content (% of DM) was 1.77% Lys, 1.04% Thr, and 0.52% Met. In Exp. 2, a total of 1,100 pigs (25 kg of BW) housed in 50 pens were fed 5 dietary regimens with 0, 7.5, 15, and 22.5% or decreasing amounts (22.5, 15, 7.5, and 0%, respectively) of EP canola meal over 4 phases to validate performance and carcass characteristics. Diets were formulated to contain equal NE: SID Lys for each growth phase (g/Mcal; 4.04, d 0 to 25; 3.63, d 26 to 50; 3.23, d 51 to 77; 2.83, d 78 to 90). At slaughter, carcass characteristics were measured for all pigs, and jowl fat was sampled for 2 pigs per pen. For d 51 to 90, the 22.5% EP canola meal regimen was reduced to 18% (22.5/18%) because of decreased ADFI in phases 1 and 2. Overall (d 0 to 90), increasing dietary EP canola meal linearly decreased (P < 0.001) ADG and ADFI and linearly increased (P < 0.01) G: F. For 0 and 22.5/18% EP canola meal, respectively, ADG was 978 and 931 g/d, ADFI was 2.77 and 2.58 kg/d, and G: F was 0.366 and 0.378. Increasing dietary EP canola meal did not alter the carcass backfat thickness, loin depth, or jowl fat fatty acid profile. Pigs fed 22.5/18% EP canola meal reached slaughter weight 3 d after (P < 0.05) pigs fed 0% EP canola meal. In summary, EP canola meal provided adequate energy and AA; however, ADG was reduced by 3 g/d per 1% of EP canola meal inclusion, likely because of increased dietary glucosinolates. Thus, the amount of EP canola meal included in swine diets should be targeted to an expected growth performance and carcass quality. Finally, diets formulated to contain an equal NE and SID AA content did not entirely eliminate the risks for reduced growth performance associated with inclusion of an alternative feedstuff.