Effects of feeding canola meal from high-protein or conventional varieties of canola seeds on growth performance, carcass characteristics, and cutability of pigs

The objectives of this experiment were to determine growth performance, visceral mass differences, carcass characteristics, fresh meat quality, and carcass cutability of growing-finishing pigs fed diets containing high-protein canola meal (CM-HP) or conventional canola meal (CM-CV). Seven dietary treatments were fed to investigate effects of increasing inclusion rates of CM-HP or CM-CV in a corn-soybean meal diet containing no canola meal (control). Inclusion rates were 33, 66, or 100% replacement of soybean meal with either CM-HP or CM-CV. Pigs (140 barrows and 140 gilts; 2 barrows and 2 gilts per pen) were fed experimental diets in 3 phases with each phase lasting 35, 28, and 28 d, respectively. Within each phase, diets were formulated to be similar in concentrations of standardized ileal digestible indispensable AA and in standardized total tract digestible P, but NE concentrations were not equalized among diets. At the conclusion of the experiment, 1 pig per pen was harvested. Over the 91-d growing-finishing period, no effects of CM-HP on ADG, ADFI, or G:F were observed, but final BW tended (P = 0.06) to be reduced as increasing levels of CM-HP were included in the diets. There was a linear increase (P < 0.05) in ADFI and a linear reduction (P < 0.05) in G:F as CM-CV inclusion level increased. Pigs fed CM-CV also had greater (P < 0.05) ADG and ADFI than pigs fed diets containing CM-HP. There was a linear increase (P < 0.01) in liver weights, as a percentage of live weight, as CM-CV inclusion increased, but that was not the case if CM-HP was included in the diets. There was a linear increase (P < 0.05) in kidney weights, as a percentage of live weight, as CM-HP or CM-CV inclusion increased. There were no differences among treatments for ending live weight, HCW, carcass yield, loin eye area, 10th rib backfat thickness, or estimated carcass lean. Shear force, cook loss, LM moisture, LM extractible lipid, and drip loss were also not different among treatment groups. There were no differences among treatments for any subjective LM quality evaluations (color, marbling, firmness). Pigs fed CM-HP had increased (P < 0.05) boneless lean cutting yields and boneless carcass cutting yields compared with pigs fed CM-CV. In conclusion, CM-HP and CM-CV may fully replace soybean meal as protein supplements in growing-finishing pig diets without substantially impairing pig performance or carcass quality.