Effects of feeding canola meal or soy expeller at two dietary net energy levels on growth performance, dressing and carcass characteristics of barrows and gilts

Abstract

Feeding solvent-extracted canola meal (CM) with relatively high-fibre content or extruded-expelled soybean cake (SE) with remaining oil content offers the opportunity to either reduce or increase dietary net energy (NE) level at low cost. In a 2×2×2 factorial design, 504 barrows and 504 gilts (33kg) were fed two NE densities (low [9.3–9.4MJ/kg for grower and finisher, respectively] or high [9.9–10.2MJ/kg]) and two supplemental protein sources (CM [250–200g/kg] or SE [150–125g/kg]). Pigs were housed by gender in 48 pens of 21 pigs each and were fed over 5 growth phases (Grower 1: d0-12, Grower 2: d13-33, Grower 3: d34-53, Finisher 1: d54-74, Finisher 2: d75-slaughter). Pen BW, feed added and orts were measured at d0, 12, 33, 53, 74, biweekly thereafter, and at slaughter weight (130kg). Warm carcasses were weighed and graded (Destron). For the overall trial (d0-74), pigs fed low NE consumed (P<0.001) 72g/d more feed than those fed high NE diets, but their NE intake was 1.17MJ/d less (P<0.001). Intake was 0.82MJ/d greater (P<0.001) for pigs fed SE that grew 37g/d faster (P<0.001) than those fed CM. Dietary NE level did not affect ADG. Feed efficiency (G:F) was 0.014kg/kg greater (P<0.001) for pigs fed high vs. low NE and 0.012kg/kg greater (P<0.001) for pigs fed SE vs. CM diets. Dressing was 6g/kg greater feeding high vs. low NE (P=0.001) or SE vs. CM diets (P<0.010). Carcass weight was 0.8kg greater (P<0.050) for pigs fed high vs. low NE; 1.4kg greater (P<0.001) for pigs fed SE vs. CM diets. Pigs fed SE averaged 2.3mm greater (P<0.001) loin depth than those fed CM. Dietary energy level or supplemental protein source had no effect on backfat depth, pork yield or carcass index. Pigs fed CM stayed 2.6 d longer (P<0.001) in the barn than those fed SE. In conclusion, feeding reduced NE diets to pigs did not result in major changes in growth performance. Abruptly introducing 250g/kg CM in the grower phase diets was a challenge to pigs. Pigs fed CM never caught up to those fed more palatable, lower fibre SE likely in part because we slightly overestimated the SID AA content of CM and slightly underestimated the NE content of SE.