271 Effect of Different Inclusions of a Multi-Component Enzyme on Performance, Nutrient Digestibility, and Ileal Amino Acid Digestibility of Young Broiler Chickens

Abstract

Abstract Previous studies demonstrated that dietary carbohydrases maintain optimal broiler performance. The objective of this experiment was to evaluate the effects of a commercial carbohydrase (ENZ) at 4 concentrations on growth performance, nutrient, and amino acid digestibility of 22-d-old broilers. The 10 experimental corn and soybean meal-based treatments were: 1) a positive control diet (PC) with phytase at 500 FTU/kg of feed (PHY), 2) a mid-control diet (MC) with a 115 kcal/kg reduction in energy + PHY, 3) a negative control diet (NC1) with a 223 kcal/kg reduction in metabolizable energy, 4-5) NC1 + ENZ at 1,000 or 3,000 xylanase units (XU)/kg (NC1A and NC1B, respectively), 6) NC1 + PHY (NC2), and 7-10) NC2 + ENZ at 1,000, 2,000, 3,000, or 4,000 XU/kg (ENZ1, ENZ2, ENZ3, and ENZ4, respectively). Day-old chicks (n = 1,000) were randomly allotted to raised floor pens with 5 birds/pen and 20 replicate pens/treatment. Pens had perforated metal platforms to allow excreta collection. On day 22, broilers were euthanized, and ileal digesta samples were collected from the entire ileum. Protein retention, nitrogen-corrected apparent metabolizable energy (AMEn), and ileal digestibility of protein and amino acids (AA) were determined. Performance data were calculated from d 6 to 22. Means were separated with the PDIFF option of SAS V9.4 PROC GLIMMIX at P ≤ 0.05. On d 22, broilers from PC and MC treatments had greater body weight (BW) than all other treatments (P < 0.0001). The least feed intake was reported in birds fed ENZ1 diet, but it was similar to NC1, NC1B, and ENZ3-fed broilers (P < 0.0472). Broilers fed PC and MC had the greatest BW gain; however, ENZ2-fed broilers were able to gain similarly as MC treatment (P < 0.0001). Broilers fed PC diet had the best feed efficiency, followed by MC-fed broilers, but these were similar to ENZ3 (P < 0.0001). Protein retention was the greatest for MC-fed broilers but was similar for NC1B and ENZ3 (P < 0.0001). AMEn was greatest for broilers fed PC and MC diets, followed by both diets that included 3,000 XU/kg (P < 0.0001). Protein digestibility was greatest for ENZ2-fed broilers (P < 0.0001) but similar to MC, NC1B, NC2, ENZ3, and ENZ3. Treatments with added PHY, excluding ENZ1, had greater lysine digestibility compared with all other treatments (P < 0.0001). Apart from threonine, ENZ4-fed broilers exhibited the greatest AA digestibility but were similar to broilers fed 2,000 or 3,000 XU/kg of ENZ (P < 0.0001). Therefore, ENZ inclusion above 1,000 XU/kg supported AA digestibility. Overall, broilers fed diets with 223 kcal/kg energy reduction and supplemented with 2,000 and 3,000 XU/kg outperformed the negative controls, which could be partially due to the utilization of dietary energy and nutrients.