Estimating equivalency values of microbial phytase for amino acids in growing and finishing pigs fitted with steered ileo-cecal valve cannulas

Abstract

Ten crossbred barrows (48.3 +/- 2.3 kg of initial BW) fitted with steered ileo-cecal valve cannulas were used to investigate the effects of supplemental microbial phytase on the apparent ileal digestibilities (AID) of AA, Ca, P, N, and DM, and the apparent total tract digestibilities of Ca, P, N, and DM. All diets were corn-soybean meal-based, and contained 0.44% Ca and 0.40% total P. Diets 1, 2, and 3 contained 12.0, 11.1, and 10.2% CP, respectively. Diets 4 and 5 had the same ingredient composition as diet 3, plus 250 and 500 U/kg phytase (Natuphos), respectively. Pigs were randomly allotted to 1 of 5 dietary treatments in a paired 5 x 5 Latin square with an extra period to test for carryover effects. Each 14-d period consisted of a 7-d adjustment followed by a 3-d total collection, a 12-h ileal digesta collection, a 3-d readjustment, and a second 12-h ileal digesta collection. Pigs were housed individually in metabolism pens (1.2 x 1.2 m). Water was supplied ad libitum, and feed was supplied at a level of 9% of the metabolic BW (BW(0.75)) per day in 2 equal daily feedings. As the dietary CP concentration increased, the AID of CP and all AA measured increased linearly (P < 0.05) with the exception of proline. In addition, the apparent total tract digestibilities (grams per day) and retention of N (grams per day) increased linearly (P < 0.01) with increasing CP levels. Supplementing diets with phytase increased the AID of Ca (P < 0.01), P (P < 0.001), CP (P = 0.07), and the AA (P < 0.10) Gly, Ala, Val, Ile, Thr, TSAA, Asp, Glu, Phe, Lys, and Arg. Protein and phytase response equations were generated for those AA affected (P < 0.10) by both CP level and phytase supplementation. Based on these equations, 500 U/kg of phytase can replace 0.52 percentage units of the dietary CP, which includes a 0.03 percentage unit improvement in Lys AID. The results of this study show that supplementing pig diets with microbial phytase improves CP and AA digestibilities in addition to Ca and P digestibilities.

Phytate-degrading enzymes in pig nutrition

“…In contrast, and Peter and Baker (2003) challenge the proposition that phytase has the capacity to enhance amino acid digestibility/protein utilisation. Nevertheless, amino acid matrix values have been recommended (Kies et al, 1997;Coelho and McKnight, 1998) and Radcliffe et al (2006) derived estimates of amino acid equivalency values for phytase. Anecdotally, many commercial pig nutritionists modify their formulations by assigning a matrix of amino acid values to microbial phytase, which is tacit acceptance of a positive 'protein effect'.…”

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

“…Digestibilidade ileal aparente (%) de nutrientes, em dietas com fitase e xilanase (unidade kg -1 dieta) para suínos em crescimento. tirosina de suínos, alimentados com dietas com fitase (850 unidades kg -1 dieta) (Tabela 4), corroboram os obtidos em estudos com dietas que continham níveis superiores a 500 unidades kg -1 de fitase, o que corresponde a acréscimo de 1 a 2% (Kemme et al, 1999) e de até 8% (Radcliffe et al, 2006) na digestibilidade ileal dos aminoácidos. Nos ingredientes, o P fítico pode formar complexos fitato-proteína.…”

“…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).…”

Un estudio de las estrategias de asignación de valor de aminoácidos a las fitasas

“…Por un efecto asociativo, la digestibilidad de otros elementos, se ve también beneficiada y se logra mejorar la digestión de la energía (2,3,4) y de los aminoácidos (5,6) . En la producción de cerdos, el incremento en el aprovechamiento del fósforo es suficiente para justificar el uso de las fitasas y el impacto en la disponibilidad de energía es de consideración (2,4) , mientras que, en el caso de los aminoácidos, los beneficios son cuestionables (7,8,9) porque la magnitud de mejoría en los coeficientes de digestibilidad es relativamente pequeña y muy variable (10) , dependiendo del ingrediente, de la dieta y del aminoácido de que se trate (11,12,13) .…”

“…Por ejemplo, el CV del requerimiento de lisina puede ser cercano al 20 % (13) , mientras que la reducción por el uso de la fitasa seguramente será menor al 5 % (6,13,14) . Adicionalmente, las dietas típicamente exceden los requerimientos promedio de la población (15) , quizá hasta en which releases nutrients, particularly the phosphorus, zinc and calcium chelates (1,2) ; by an associative effect, energy (2,3,4) and (5,6) amino acids digestibility is also improved. In pig production, increased phosphorus utilization is sufficient to justify the phytase dietary addition, but the impact on energy availability is of consideration (2,4) , while, in the case of amino acids, the benefits are questionable (7,8,9) because the magnitude of improvement in digestibility coefficients is relatively small and highly variable (10) , depending on diet ingredients, and factorially, on the amino acid in question (11,12,13) .…”