Evaluation through literature data on standardized ileal digestibility and basal ileal endogenous loss of amino acids associated with barley in pigs

Abstract

This meta-analysis aimed to estimate the standardized ileal digestibility (SID) and the basal ileal endogenous amino acid losses (IAA end ) in barley for growing pigs. In total, 38 different barley treatments published in 26 peer-reviewed papers were used for the meta-analysis containing information on dietary composition including amino acid (AA) contents of the assay diets, and (or) barley samples, as well as apparent ileal digestibility (AID) of AA in barley. The SID of AA was determined by either correcting AID of AA for their IAA end or by regression analysis between the apparent ileal digestible and total dietary AA contents. The SID values obtained by correcting the AID values for their IAA end amounted to 70%, 77%, 74% and 63% for Lys, Met, Thr and Trp, whereas those based on regression analysis method were 82%, 82%, 69% and 55%, respectively. Estimates of basal ileal endogenous loss of CP in ileal digesta varied considerably and averaged 11.84 g/kg dry matter intake (DMI), whereas IAA end for indispensable AA ranged from 0.05 g/kg DMI for Trp to 1.90 g/kg DMI for Leu. In most cases, these estimates were considerably higher than previously reported values for IAA end . The results of the present regression analysis indicate for most AA higher SID values compared with SID of most AA that were obtained by correcting AID values for IAA end . In view of the observed high variations in IAA end and the low CP content of the barley samples, estimating SID of AA based on literature data by means of the regression method may improve accuracy of SID coefficients for barley. In contrast, transformation of AID values into their corresponding SID values by using a constant correction factor for IAA end adds an additional source of error, thereby reducing the precision in estimating SID of AA.Keywords: amino acids, meta-analysis, pigs, standardized ileal digestibility, barley ImplicationsRegression analyses between the apparent ileal digestible and the total dietary amino acid (AA) content in barley samples have proven to be superior over the calculation of standardized ileal digestibility (SID) by correcting apparent ileal digestibility (AID) values for their ileal endogenous amino acid (IAA end ). According to regression analysis, SID of most AA in barley was >80%, whereas SID of most AA obtained by correcting AID values for IAA end was below 80%. In particular, lower SID of Lys, Thr and Trp in comparison to other indispensable AA need to be compensated for, for example, through supplementation with crystalline AA in barley diets for pigs. IntroductionThe world production of barley amounts to over 134 million tons annually (FAOSTAT, 2011), therefore, and due to its low purchase cost, barley is the most important crop in diets for livestock after wheat and maize (Leterme et al., 2000;Hennig et al., 2006; FAOSTAT, 2011). The protein content of cereal grains including barley is considerably lower than that of protein supplements such as soya bean meal, but due to their high dietary inclusion level, cereal grains can su...

Standardized ileal digestibility of amino acids in eight genotypes of barley fed to growing pigs

“…Mean contents of CP and indispensable AA (in % of CP) in the barley genotypes, except for Yool, were lower when compared with reported values (NRC, 2012), but still within the range of tabulated values of Evonik Degussa (2010) and Spindler et al (2014). The SID of indispensable AA in the barley genotypes was between 3% and 12% units lower when compared to values summarized in current feed tables (Evonik Degussa, 2010;CVB, 2011;NRC, 2012), whereas SID of His, Ile, Leu, Met, Val and Cys in the genotype Travira was close to these reported values.…”

“…For livestock feeding, especially for growing pigs, 37 million tons of barley are annually used in the European Union (FAOSTAT, 2013). Its CP content varies considerably, ranging between 7.3% and 16.1% dry matter (DM; Spindler et al, 2014), and is low compared to protein ingredients such as soybean meal. However, due to high dietary inclusion levels, barley can supply usually up to half of the feed protein in pig diets.…”

“…Standardized ileal digestibility (SID) of AA in barley has been summarized in several feed tables (e.g. Evonik Degussa, 2010;NRC, 2012), but according to the results of a recently performed metaanalysis by Spindler et al (2014), there is a great variation in SID of AA compared to data compiled in these feed tables.…”

“…Changes in environmental conditions during growing season but also genetic variations among barley genotypes have been shown to be responsible for differences in nutrient content between barley samples (Bach Knudsen, 1997;Spindler et al, 2014). These differences may also affect SID of AA, however, information on both chemical composition and SID of AA in new genotypes of barley is lacking.…”

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

“…Por ejemplo, el incremento promedio en la digestibilidad ileal verdadera o estandarizada de todos los aminoácidos esenciales por efecto de fitasa, puede estar en el orden de 3.5 unidades porcentuales (12,14,15) , pero el coeficiente de variación (CV) de la digestibilidad inherente llegar a más del 30 % (12) . En la práctica, no se pondera la variación por la potencial liberación de aminoácidos a la acción de las fitasas y normalmente se asignan valores matriciales, lo que equivale a una reducción fija de la demanda y, por lo tanto, del aporte de nutrientes por los ingredientes, que redunda en un ahorro en el costo de las dietas.…”