Ileal amino acid digestibility and performance of growing pigs fed wheat-based diets supplemented with xylanase

Abstract

Two experiments were conducted to determine the effect of supplementation of xylanase to a wheat-based diet on the apparent ileal digestibility (AID) of AA and the performance of growing pigs fed diets limiting in AA. In Exp. 1, eight pigs (average initial BW = 20.5+/-1.2 kg) fitted with a simple T-cannula at the distal ileum, were fed four diets according to a repeated 4 x 4 Latin square design. Diet 1 was a basal diet that contained 97.6% wheat. Diets 2, 3, and 4 were the basal diet supplemented with xylanase at rates of 5,500, 11,000, and 16,500 units of xylanase activity (XU), respectively (as-fed basis). There were linear and quadratic effects (0.062 < P < 0.001) of xylanase supplementation on the AID of CP and most of the AA. The largest increases in AID of CP and AA were obtained when xylanase was supplemented at a rate of 11,000 XU; no further increases were observed with xylanase supplementation at a rate of 16,500 XU. In Exp. 2, 30 pigs (average initial BW 21.4+/-1.8 kg) were randomly allotted to six dietary treatments. Diets 1 to 4 were similar to those used in Exp. 1. Diet 5 was the same as Diet 1, but supplemented with 0.53% lysine, 0.12% threonine, and 0.05% methionine. Diet 6 (positive control diet) was a wheat-soybean meal diet that contained 18.2% CP (as-fed basis). The total contents of lysine, threonine, and methionine were similar for Diets 5 and 6. There was a linear effect of xylanase supplementation on ADG (P = 0.093) and feed:gain ratio (P = 0.089), and a quadratic effect on ADG (P = 0.067) and feed:gain ratio (P = 0.074). But, the greatest response was obtained with the supplementation of 11,000 XU. The supplementation of lysine, threonine, and methionine to Diet 1 increased (P = 0.001) ADG and ADFI and improved (P = 0.01) feed:gain ratio. There was no difference (P = 0.508) in the performance of pigs fed the AA-supplemented or control diet. In conclusion, the supplementation of xylanase to a diet in which wheat provided the sole source of protein and energy improved the AID of AA, ADG, and feed:gain ratio; however, this improvement was very small compared with that obtained with the supplementation of synthetic amino acids.

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

“…Esse mecanismo pode explicar, em parte, o aumento observado na digestibilidade ileal dos aminoácidos. Além disso, a ação da xilanase pode variar entre aminoácidos, uma vez que a quantidade de polissacarídeos não amiláceos na dieta altera a amplitude das respostas (Yin et al, 2000a;Barrera et al, 2004).…”

“…As equações obtidas confirmam que a ação da xilanase aumenta a digestibilidade ileal dos aminoácidos essenciais e não essenciais em 2 a 3%. No entanto, os estudos indicam variações quanto aos aminoácidos que apresentam melhor digestibilidade ileal aparente (Yin et al, 2000a;Barrera et al, 2004;Nortey et al, 2008;Woyengo et al, 2008). Um dos mecanismos de ação da xilanase sobre a digestibilidade dos aminoácidos está relacionado à redução da barreira física entre enzimas e substrato (Yin et al, 2000b).…”

“…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).…”

Expression of cationic amino acid transporters, carcass traits, and performance of growing pigs fed low-protein amino acid-supplemented versus high protein diets

“…Some reports show that a reduction of four or less CP percentage units in corn-soybean meal (SBM) diets does not affect the performance and carcass characteristics of finishing pigs (Tuitoek et al, 1997;Knowles et al, 1998;Le Bellego et al, 2002). Moreover, Barrera et al (2004) showed that free Lys and Thr could replace SBM completely in wheat diets for growing pigs without affecting their performance. However, other reports show a decreased performance and thicker back fat when CP was reduced by four or more percentage units in cornor sorghum-SBM diets (e.g., Brudevold and Southern, 1994;Tuitoek et al, 1997;Yue and Qiao, 2008).…”

“…A recent report shows that the dietary content of Leu and Lys affects the absorption of Lys (García-Villalobos et al, 2012). F-AA diets not only contain lower Arg and Leu levels but also a high percentage of free Lys, from 44% (Kerr et al, 2003) to 70% (Barrera et al, 2004) of total Lys. Since protein-bound AA need to be released by pancreatic and intestinal enzymes prior to their absorption, free AA may be absorbed faster and their availability for protein synthesis could be higher (Rerat et al, 1992).…”