293
Enzyme Supplementation to Improve Soy Hull Value in Finishing Diets
Soybean hulls are a byproduct of soybean processing, often priced competitively for consideration in swine diets. Their use in swine diets is limited by concerns of digestibility and energy content of the ration. However use of exogenous enzymes in diets containing soy hulls may enable higher inclusion rates without reducing growth performance. The purpose of this study was to evaluate the efficacy of a commercially available enzyme with protease and carbohydrase activity when added to either corn-soybean meal based diets, or diets containing 20% soy hulls. One hundred twenty eight pigs (78.08 +/- 9.1 kg) were allotted to 16 pens and randomly assigned one of four treatments offered in two phases (grower 68-91 kg, and finisher 91-125 kg). Dietary treatments were 1) corn- SBM 2) 1 + 1,000 ppm enzyme mixture; 3) corn-SBM + 20% soy hulls and 4) 3 + 1,000 ppm enzyme mixture. Pen served as the experimental unit. Pigs were offered dietary treatments on an ad libitum basis. Pig weight and feed disappearance were measured every 14 days until all pigs averaged 125 kg (49 days). Criterion of interest were ADG, ADFI and G:F within phase. Three pigs were removed during the study due to poor performance (2) or death (1), none of which were related to dietary treatments. Daily feed intake data for these pens were adjusted for pig-days at removal. Data were analyzed using the Proc Mixed function of SAS (SAS Inst. Inc. Cary, NC) with treatment and replicate in the model. Treatment LS means were separated using the PDIFF function and considered significant at P < 0.05. Dietary treatments did not alter ADG (1.00, 1.11, 0.86, 1.10 kg/d for treatments 1-4, respectively), ADFI (2.52, 2.45, 2.19, 2.26 kg/d) nor G:F during the grower phase (P > 0.12). In the finisher phase, however ADG for pigs fed treatment 2 was greater than pigs fed treatment 1 (0.98 vs. 0.83 kg/d; P = 0.02), 3 (0.81 kg/d; P = 0.013), and tended to be greater than pigs fed treatment 4 (0.86 kg/d; P = 0.051). Neither ADFI nor G:F were impacted by the treatments during the finisher phase. These data suggest enzyme supplementation improves finisher ADG, but does not impact ADFI, G:F, nor grower performance.
Keywords: Enzyme; Soy Hulls, Pigs