title: Effects of xylanase supplementation on the apparent digestibility and digestible content of energy, amino acids, phosphorus, and calcium in wheat and wheat by-products from dry milling fed to grower pigs.
abstract: Wheat by-products are feedstuffs that vary in nutritional value, partly because of arabinoxylans that limit nutrient digestibility. Millrun is a byproduct from dry milling wheat into flour and contains varying amounts of the bran, middlings, screening, and shorts fractions. The digestible nutrient content of mill-run is not well known. Effects of xylanase supplementation (0 or 4,000 units/kg of diet) on energy, AA, P, and Ca digestibilities were studied in a wheat control diet and 5 diets containing 30% of a by-product (mill-run, middlings, shorts, screening, or bran) in a 2 x 6 factorial arrangement of treatments. The wheat control diet was formulated to contain 3.34 Mcal of DE/kg and 3.0 g of standardized ileal digestible Lys/Mcal of DE. Diets contained 0.4% chromic oxide. Each of 12 ileal-cannulated pigs (32.5 +/- 2.5 kg) was fed 6 or 7 of 12 diets at 3 times the DE requirement for maintenance in successive 10-d periods for 6 or 7 observations per diet. Feces and ileal digesta were each collected for 2 d. Xylanase tended to increase (P < 0.10) ileal energy digestibility by 2.2 percentage units and the DE content by 0.10 Mcal/kg of DM and increased (P < 0.05) ileal DM digestibility by 2.8 percentage units; a diet x xylanase interaction was not observed. Xylanase increased (P < 0.05) total tract energy and DM digestibilities and the DE content. A diet x xylanase interaction was observed; xylanase increased (P < 0.05) total tract energy digestibility of the millrun diet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kg of DM, and DM digestibility from 71.5 to 78.6%. Diet affected (P < 0.05) and xylanase improved (P < 0.05) digestibility and digestible contents of some AA in diets and by-products, including Lys, Thr, and Val. Xylanase increased (P < 0.05) Lys digestibility by 13.8, 5.0, 5.2, 6.0, and 14.1 percentage units in millrun, middlings, shorts, screening, and bran, respectively. Diet affected (P < 0.01) total tract P and Ca digestibilities. Xylanase increased (P < 0.05) digestible P and Ca contents. In summary, nutrient digestibility varies among wheat by-products. Millrun contained 2.65 Mcal of DE/kg of DM, which xylanase increased to 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibility and DE content in wheat by-products; and the extent of improvement depended on the by-product. Xylanase supplementation may maximize opportunities to include wheat byproducts in swine diets and ameliorate reductions in nutrient digestibility that may be associated with arabinoxylans.
authors.affiliation: Prairie Swine Centre Inc., Saskatoon, Saskatchewan, Canada.
authors.forename: T N
authors.initials: TN
authors.lastname: Nortey
authors.forename: J F
authors.initials: JF
authors.lastname: Patience
authors.forename: J S
authors.initials: JS
authors.lastname: Sands
authors.forename: N L
authors.initials: NL
authors.lastname: Trottier
authors.forename: R T
authors.initials: RT
authors.lastname: Zijlstra
mesh_terms: D000596:Amino Acids / Q000032:analysis; D000821:Animal Feed; D000818:Animals; D002118:Calcium / Q000032:analysis; D004043:Dietary Fiber / Q000032:analysis; D019587:Dietary Supplements; D004063:Digestion / Q000502:physiology*; D043364:Endo-1,4-beta Xylanases / Q000008:administration & dosage / Q000378:metabolism; D002149:Energy Intake / Q000502:physiology; D008297:Male; D010758:Phosphorus / Q000032:analysis; D013552:Swine / Q000378:metabolism*; D014908:Triticum / Q000737:chemistry / Q000378:metabolism
chemical_list: D000596:Amino Acids; D004043:Dietary Fiber; D010758:Phosphorus; D043364:Endo-1,4-beta Xylanases; D002118:Calcium