Effects of individual or combined xylanase and phytase supplementation on energy, amino acid, and phosphorus digestibility and growth performance of grower pigs fed wheat-based diets containing wheat millrun1

Abstract

The objective of these studies was to determine if dietary enzymes increase the digestibility of nutrients bound by nonstarch polysaccharides, such as arabinoxylans, or phytate in wheat millrun. Effects of millrun inclusion rates (20 or 40%), xylanase (0 or 4,375 units/kg of feed), and phytase (0 or 500 phytase units/kg of feed) on nutrient digestibility and growth performance were investigated in a 2 x 2 x 2 factorial arrangement with a wheat control diet (0% millrun). Diets were formulated to contain 3.34 Mcal of DE/kg and 3.0 g of true ileal digestible Lys/Mcal of DE and contained 0.4% chromic oxide. Each of 18 cannulated pigs (36.2 +/- 1.9 kg of BW) was fed 3 diets at 3x maintenance in successive 10-d periods for 6 observations per diet. Feces and ileal digesta were collected for 2 d. Ileal energy digestibility was reduced (P < 0.01) linearly by millrun and increased by xylanase (P < 0.01) and phytase (P < 0.05). Total tract energy digestibility was reduced linearly by millrun (P < 0.01) and increased by xylanase (P < 0.01). For 20% millrun, xylanase plus phytase improved DE content from 3.53 to 3.69 Mcal/kg of DM, a similar content to that of the wheat control diet (3.72 Mcal/kg of DM). Millrun linearly reduced (P < 0.01) ileal digestibility of Lys, Thr, Met, Ile, and Val. Xylanase improved (P < 0.05) ileal digestibility of Ile. Phytase improved ileal digestibility of Lys, Thr, Ile, and Val (P < 0.05). Millrun linearly reduced (P < 0.05) total tract P and Ca digestibility and retention. Phytase (P < 0.01) and xylanase (P < 0.05) improved total tract P digestibility, and phytase and xylanase tended to improve (P < 0.10) P retention. Phytase improved Ca digestibility (P < 0.05) and retention (P < 0.01). The 9 diets were also fed for 35 d to 8 individually housed pigs (36.2 +/- 3.4 kg of BW) per diet. Millrun reduced (P < 0.05) ADFI, ADG, and final BW. Xylanase increased (P < 0.05) G:F; phytase reduced (P < 0.05) ADFI; and xylanase tended to reduce (P = 0.07) ADFI. In summary, millrun reduced energy, AA, P, and Ca digestibility and growth performance compared with the wheat control diet. Xylanase and phytase improved energy, AA, and P digestibility, indicating that nonstarch polysaccharides and phytate limit nutrient digestibility in wheat byproducts. The improvement by xylanase of energy digestibility coincided with improved G:F but did not translate into improved ADG.

Nutritive value of wheat and wheat by-products in pig nutrition: A review

“…This is in accordance with results from a study by Nortey et al (2008) with grower pigs, where ATTD of energy and DM and AID of DM and some AA was improved significantly when a diet based on 833 g wheat or 533 g wheat and 300 g wheat by-product/kg diet was supplemented with xylanase (4000 U/kg diet as-fed). Graded millrun inclusion (200 and 400 g/kg as-fed) in a wheat-based diet fed to grower pigs and supplementation with xylanase (4375 U/kg diet as-fed) or phytase (500 U/kg diet as-fed) resulted in an increased AID of energy and some AA (Nortey et al, 2007b). The relevance of dietary inclusion level of enzymes is reflected in a study of Emiola et al (2009) with grower pigs.…”

Meta-análise da digestibilidade ileal de aminoácidos e minerais em suínos alimentados com dietas contendo enzimas

“…A melhor digestibilidade dos aminoácidos, em suínos alimentados com dietas com fitase, pode ser explicada pela ação direta da enzima sobre o fitato que reduz a formação de complexos. No entanto, os efeitos da fitase sobre a digestibilidade dos aminoácidos ainda é contraditório Nortey et al, 2007).…”

“…A base de dados totalizou 21 artigos, publicados em periódicos internacionais entre 1998 e 2009 (moda: 2008), dos quais 12 avaliaram fitase e 9 avaliaram xilanase (Valaja et al, 1998;Kemme et al, 1999;Selle et al, 2000;Yin et al, 2000aYin et al, , 2000bJondreville et al, 2001;Kies et al, 2001;Traylor et al, 2001;Barrera et al, 2004;Cervantes et al, 2004;Liao et al, 2005;Lyberg et al, 2006;Nyachoti et al, 2006;Radcliffe et al, 2006;Lindberg et al, 2007;Nortey et al, 2007Nortey et al, , 2008Pomar et al, 2008;Woyengo et al, 2008Woyengo et al, , 2009 A meta-análise constituiu-se de três análises sequenciais: gráfica, para controlar a qualidade da base e observar a coerência biológica dos dados; de correlação entre as diversas variáveis, para identificar os fatores relacionados na base; e de variância-covariância. Foram utilizados, nos modelos para as análises de variância-covariância, os fatores com coeficientes de correlação mais elevados e as codificações para os efeitos inter ou intraestudos (Lovatto et al, 2007).…”

“…Portanto, além de interferir na disponibilidade de fósforo, o fitato pode quelatar cátions de Ca, Mg, Fe, Zn e Cu e comprometer a digestibilidade dos aminoácidos (Kies et al, 2001). Assim, em suínos, a utilização de PNAs e de P fítico é limitada pela baixa produção de enzimas específicas pelo trato gastrintestinal (Nortey et al, 2007(Nortey et al, , 2008. A xilanase, por sua vez, atua sobre as frações de fibra da dieta, das quais a celulose e a hemicelulose são as principais fontes de substrato para esta enzima .…”

Role of Exogenous Fibrolytic Enzymes in Ruminant Digestion - A Review

“…Negative effects of fibre on nutrient digestion can be reduced by supplementation of multienzyme in diets such as xylanase, β-glucanase and cellulase (Degen et al, 2007).These enzymes partially hydrolyze NSP and thereby increase nutrient digestibility (Barrera et al, 2003;Nortey et al, 2007). Supplementation of multienzyme in proper combination and proportion play an important role in efficient and effective nutrient utilization of diets containing high fibre (Zijlstra et al, 2010).…”