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

doi:10.2527/jas.2007-0472

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ANIMAL NUTRITION

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 pigs¹^,2

T. N. Nortey^*^,^,, J. F. Patience^*, J. S. Sands, N. L. Trottier^# and R. T. Zijlstra^,3

^* Prairie Swine Centre Inc., Saskatoon, Saskatchewan, Canada, S7H 5N9; and Department of Animal and Poultry Science, University of Saskatchewan, Saskatoon, Saskatchewan, Canada, S7N 5A8; and Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, Canada, T6G 2P5; and Danisco Animal Nutrition, Marlborough, United Kingdom, SN8 1AA; and ^# Department of Animal Science, Michigan State University, East Lansing 48824

³ Corresponding author: ruurd.zijlstra{at}ualberta.ca

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 andcontains varying amounts of the bran, middlings, screening,and shorts fractions. The digestible nutrient content of mill-runis not well known. Effects of xylanase supplementation (0 or4,000 units/kg of diet) on energy, AA, P, and Ca digestibilitieswere studied in a wheat control diet and 5 diets containing30% of a by-product (mill-run, middlings, shorts, screening,or bran) in a 2 x 6 factorial arrangement of treatments. Thewheat control diet was formulated to contain 3.34 Mcal of DE/kgand 3.0 g of standardized ileal digestible Lys/Mcal of DE. Dietscontained 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 timesthe DE requirement for maintenance in successive 10-d periodsfor 6 or 7 observations per diet. Feces and ileal digesta wereeach collected for 2 d. Xylanase tended to increase (P <0.10) ileal energy digestibility by 2.2 percentage units andthe 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 xylanaseinteraction 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 millrundiet from 72.1 to 78.9%, DE content from 3.19 to 3.51 Mcal/kgof DM, and DM digestibility from 71.5 to 78.6%. Diet affected(P < 0.05) and xylanase improved (P < 0.05) digestibilityand 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 percentageunits 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 increasedto 3.56 Mcal of DE/kg of DM. Xylanase improved nutrient digestibilityand DE content in wheat by-products; and the extent of improvementdepended on the by-product. Xylanase supplementation may maximizeopportunities to include wheat byproducts in swine diets andameliorate reductions in nutrient digestibility that may beassociated with arabinoxylans.