Effects of feeding canola press-cake on diet nutrient digestibility and growth performance of weaned pigs

Canola press-cake (CPC) is a co-product of biodiesel production from small to medium-scale processing plants that mechanically press canola seed without pre-pressing conditioning, flaking, cooking and post-pressing solvent extraction. The CPC contains 370 g/kg CP and 204 g/kg remaining oil. Thus, CPC could be a source of AA and energy in pig diets. Growth responses to increasing dietary CPC inclusion have not been extensively evaluated in young pigs. In total, 240 pigs (7.5 ± 0.31 kg) starting 1 week after weaning at 19 d of age were fed five wheat-based diets containing 0, 50, 100, 150, or 200 g/kg CPC replacing soybean meal in two phases (Phase 1 and 2). Diets were formulated to contain 10.3 and 10.1 MJ NE/kg and 1.2 and 1.0 g standardised ileal digestible (SID) Lys/MJ NE, respectively, and were fed for 2 weeks as Phase 1 (day 0-14) and 3 weeks as Phase 2 (day 15-35). Feed added and remaining and individual pigs were weighed weekly to calculate average daily feed intake (ADFI), average daily weight gain (ADG) and feed efficiency (G:F) per pen (four pigs per pen). Freshly-voided faeces were collected on day 12 and 13 and day 33 and 34 for Phase 1 and 2, respectively, to determine diet apparent total tract digestibility coefficient (CATTD) of gross energy (GE), crude protein (CP) and digestible energy (DE) value. Increasing dietary inclusion of CPC linearly reduced (P < 0.05) the CATTD of GE, diet DE and calculated NE values for Phase 1 and 2. Increasing dietary inclusion of CPC did not affect overall (d 0-35) ADFI and ADG of pigs, but quadratically reduced (P < 0.05) ADFI for day 29-35, linearly increased (P < 0.05) ADG for day 15-21 and linearly reduced (P < 0.05) ADG for day 29-35. Increasing CPC inclusion linearly increased (P < 0.05) G:F for the overall trial and day 15-21 and quadratically increased (P < 0.05) G:F for day 8-14. In conclusion, feeding up to 200 g/kg of CPC reduced CATTD of GE and CP, but did not affect overall growth performance of weaned pigs fed phase diets balanced for NE and SID Lys/NE ratio.