246 Evaluation of the Complete Replacement of Soybean Meal by Rapeseed Meal on Performance and Carcass Composition of Grow-Finishing Pigs

Abstract

Abstract The aim of this experiment was to evaluate the effects of replacing soybean meal (SBM) by rapeseed meal (RSM) as main protein source in diets for grow-finishing pigs. The trial included a total of 1,248 crossbred boars and gilts [Pietrain x (Landrace x Large White), with an initial body weight (BW) of 38.3 ± 5.29 kg (Mean ± SD)], distributed in 96 pens of 13 pigs. Pens were randomly distributed in 2 dietary treatments, balanced by BW, block and sex within each of the 8 slurry pits. The inclusion of SBM and RSM in the growing diets was 13.8% and 20.0%, whereas in the finishing diets (days 52-91) was 10.5% and 14.4%, respectively. Diets were formulated to have the same net energy (NE) value and crude protein differences were below 0.5%. To achieve isoenergetic diets, the inclusion of animal fat was increased by 2.4% and 1.7% in RSM diets compared with SBM for the growing and finishing phases, respectively. Standardized ileal digestible (SID) Lys was kept at 0.95% and 0.86% in the growing and finishing phases, respectively. Performance variables were analyzed by using a linear mixed model with treatment and sex as fixed effects and initial BW as covariate, while pit was included as a random effect. Individual carcass data were analyzed in a linear mixed model with treatment, sex and marketing group as fixed effects, and hot carcass weight as a covariate, and pen within a pit as random effect. During the growing phase, pigs showed lower ADFI when fed the RSM diet (1.68 vs. 1.62 kg; P = 0.002) that resulted in decreased ADG (0.842 vs. 0.803 kg; P = 0.015), but FCR was not affected (2.00 vs. 2.02; P = 0.459). Contrarily, in the finishing phase, ADFI was not significantly reduced (1.98 vs. 1.95 kg; P = 0.586) but less FCR was observed when feeding RSM (2.59 vs. 2.49; P = 0.007). Final BW was not significantly affected (112.0 vs. 110.7 kg; P = 0.404), but hot carcass weight tended to be less in RSM fed pigs (92.2 vs. 91.3 kg; P = 0.078). No significant differences were reported on carcass yield (P = 0.815), carcass leanness (P = 0.850) or backfat thickness (P = 0.850). In conclusion, feeding growing pigs diets without SBM might negatively affect their performance during the growing phase, but those effects can be partly counteracted in the finishing phase without modifying carcass composition.