Effects of diet energy concentration and an exogenous carbohydrase on growth performance of weanling pigs fed diets containing canola meal produced from high protein or conventional canola seeds

The objectives were to determine effects of diet NE and an exogenous carbohydrase on growth performance and physiological parameters of weanling pigs fed a corn-soybean meal (SBM) diet or diets containing high protein canola meal (CM-HP) or conventional canola meal (CM-CV). A total of 492 pigs (initial BW: 9.15 ± 0.06 kg) were used in a randomized complete block design with 12 dietary treatments and 9 pens per treatment. A control diet based on corn and SBM and 4 diets containing 20% or 30% CM-HP or 20% or 30% CM-CV were formulated to a similar NE by adjusting inclusion of choice white grease. Four additional diets also contained 20% or 30% CM-HP or 20% or 30% CM-CV, but no additional choice white grease, and NE in these diets, therefore, was less than in the control diet. The control diet and the diets containing 30% CM-HP or CM-CV without increased choice white grease were also formulated with inclusion of an exogenous carbohydrase. Pigs were fed experimental diets for 22 d and 1 pig per pen was sacrificed at the conclusion of the experiment. Results indicated that compared with the control diet, there was no impact of canola meal on final BW, ADG, ADFI, or G:F, but pigs fed CM-CV had greater (P < 0.05) final BW, ADG, and ADFI than pigs fed CM-HP, and pigs fed diets with reduced NE had greater (P < 0.05) ADG and ADFI than pigs fed diets with constant NE. Only minor effects of CM-HP or CM-CV on intestinal weight, gut fill, digesta pH, cecal VFA concentrations, and serum concentrations of urea N, total N, or albumin were observed, but the weight of the thyroid gland increased (P < 0.05) as the concentration of dietary canola meal increased. Serum concentrations of IgG were reduced if canola meal was included in the diets without the carbohydrase, but that was not the case if the carbohydrase was included in the diet (interaction, (P < 0.05). In conclusion, up to 30% CM-HP or CM-CV in diets fed to weanling pigs from 2 wk postweaning did not impact growth performance cosmpared with pigs fed a corn-SBM diet, and NE in diets containing canola meal does not have to be similar to that of corn-SBM diets. However, inclusion of CM-CV containing 4.43 μmol/g glucosinolates in the diets resulted in improved growth performance compared with inclusion of CM-HP containing 12.60 μmol/g glucosinolates.