Determination of Phytase Activity in Feed: Interlaboratory Study

Abstract

An interlaboratory study was conducted to determine the performance characteristics of a new method for the determination of phytase activity in feed samples. The method is based on the principle that inorganic phosphate is released from the substrate phytate under defined assay conditions and has been validated for its suitability to measure the enzyme activity of various phytase products. Two different experimental designs of the study were applied, allowing for the estimation of the precision of the method under repeatability, intermediate precision and reproducibility conditions, respectively. The relative standard deviation for repeatability (RSDr) ranged from 2.2 to 10.6 and the RSD for reproducibility (RSDR) ranged from 5.4 to 15. The suitability of the validated method for the intended purpose was demonstrated. The obtained performance profile of the method validated in this study was comparable to that of similar methods that were exclusively validated for one phytase product.

Efficacy of different commercial phytase enzymes and development of an available phosphorus release curve for Escherichia coli-derived phytases in nursery pigs12

“…Because of these intrinsic differences between commercial phytase sources, the validity of using the standard AOAC method to analyze phytase activity of all products for either regulatory or comparative purposes has been questioned (Isaksen and Dalsgaard, 2007;Gizzi et al, 2008). First, the method was developed and validated using A. niger phytase, which is also the standard reference for the assay.…”

Uso de líquido ruminal en agua de bebida de pollos broiler criados en condiciones de altura

“…Peso vivo promedio de pollos BB Cobb (g) hasta los 21 días de edad por tratamiento (proporción de líquido ruminal en el agua de bebida), según sexo Si bien en el presente estudio no se emplearon aditivos enzimáticos comerciales ni aditivos nutricionales, el líquido ruminal adicionado al agua de bebida indicaría una mejor utilización de la energía que se encuentra en los carbohidratos complejos no solubles como la celulosa, pentosanos, β-glucanos y oligopolisacáridos (Gracia et al, 2003;Krás et al, 2013), que las enzimas propias del pollo no las pueden digerir (Batal y Parsons, 2004; Zelenka y Ceresnakova, 2005). Asimismo, el líquido ruminal estaría contribuyendo con vitaminas del complejo B, vitamina K, aminoácidos libres y otros nutrientes (Santschi, 2005;Rakotoarivonina et al, 2014); y adicionalmente, la hidrolisis del ácido fítico incrementa la disponibilidad de fósforo, zinc y otros nutrientes esenciales que estaban ligados al ácido fítico (Gizzi et al, 2008). Esto habría permitido mejorar las ganancias de peso a los 21 días de la crianza (p<0.01).…”

“…La flora microbiana de las aves alberga microorganismos que cumplen un papel importante en los procesos digestivos y de protección frente a los agentes patógenos (Waite y Taylor, 2014); sin embargo, las aves no están capacitadas para utilizar adecuadamente las dietas vegetales ricas en fibra (Svihus et al, 2005;Tester et al, 2006;Singh et al, 2010), por lo que se ha evaluado el uso de fitasas (Gizzi et al, 2008; Brask-Pedersen et al, 2011, 2013) y complejos multienzimáticos a base de celulasa, xilanasa, â-glucanasa, amilasa, proteasa, pectinasa y lipasa, entre otras (Jiang et al, 2008;Olukosi et al, 2008;Murphy et al, 2009; Amerah et al, 2009; Svihus, 2014; Dhama et al, 2014), a fin de mejorar el incremento de peso, la eficiencia alimenticia y la retención de fósforo fítico y fósforo total, entre otros minerales y nutrientes esenciales.…”

Microbial production of phytases for combating environmental phosphate pollution and other diverse applications

“…Weaver et al (2009) determined the effects of assay conditions on activity evaluations of two phytases (A. niger PhyA and E. coli AppA2) and compare the biochemical characteristics at a pH of 3.5, which is found similar to the stomach. In this study, three major phytase assay methods (Engelen et al, 2001;Gizzi et al, 2008) were used: the molybdenum blue method (method 1; Chen et al, 1956;Han et al, 1999;Augspurger et al, 2003), the molybdo-vanadate method (Engelen et al, 1994;Leeson et al, 2000;Huang et al, 2006) and the acetone phosphomolybdate method (method 3; Heinonen and Lahti, 1981). The determination of activities with these three assay methods of AppA2 compared to PhyA activities showed much greater variation pointing to caution in interpreting the feeding efficiency based on assay conditions.…”