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Effect of feeding diets containing 40% distillers dried grains with solubles (DDGS) and supplemented with minimally refined cottonseed oil or crude glycerol on growth performance and carcass composition of growing-finishing pigs
Feeding corn-soybean meal diets containing > 20% DDGS reduces fat firmness in pork carcasses, but supplementing these diets with cottonseed oil or crude glycerol may improve pork fat firmness. However, the addition of cottonseed oil or crude glycerol in 40% DDGS diets for growing-finishing pigs has not been evaluated. Thus, the objective of this study was to assess the effect of feeding crude glycerol or minimally-refined cottonseed oil on growth performance and carcass composition of growing-finishing pigs. Mixed sex pigs (n = 216; initial BW = 24 ± 4 kg) were blocked by BW and allotted to 1 of 3 dietary treatments: 1) a basal corn-soybean meal diet with 40% DDGS (CON); 2) CON plus 5% minimally-refined cottonseed oil (COT); or 3) CON plus 8% crude glycerol for the last 6 wk before harvest (GLY). Although diets were not isocaloric, AA to ME ratios were equal among diets within each of the 3 feeding phases. Carcass composition was estimated using real-time ultrasound 2 d before harvest. Overall, ADFI of pigs fed COT (2.30 kg/d) was less (P < 0.01) than pigs fed CON and GLY (2.47 and 2.49 kg/d, respectively). Pigs fed COT (0.93 kg/d) had greater (P < 0.01) ADG compared with pigs fed CON and GLY (0.88 and 0.87 kg/d, respectively). Greater (P < 0.01) G:F was observed for pigs fed COT (0.41) than pigs fed CON and GLY diets (0.36 and 0.35, respectively). Final BW of pigs fed COT (124.3 kg) was greater (P < 0.01) than pigs fed CON (118.9 kg) and GLY (118.6 kg). Consequently, pigs fed COT had greater (P < 0.01) HCW (94.9 kg) compared with CON and GLY fed pigs (89.9 and 89.2 kg, respectively). No differences were observed for dressing percentage (75.7, 76.3, and 75.3%), fat-free lean percentage (50.5, 49.7, and 50.0%), backfat depth (2.11, 2.26, and 2.22 cm) and LM area (42.9, 44.2, and 42.5 cm2) for CON, COT and GLY, respectively. In conclusion, pigs fed COT had improved growth performance, which was likely due to greater energy density of diets, but carcass composition was not affected by dietary treatments.
Keywords: Cottonseed oil, glycerol, growing-finishing pigs