| Summary: | <p> Determination of metabolizable energy (<b>ME</b>) and amino acid (<b>AA</b>) digestibility values of single feed indigents continues to be two of the most important aspects for successful least-cost poultry feed formulation. It would be advantageous if a common diet type could be utilized to determine both ME and AA digestibility values of feed ingredients within a single assay. Two experiments were conducted to evaluate the effect of basal diet type and excreta collection method on the ME value of single feed ingredients determined in broiler chicks using the regression method. In experiment 1, the objective was to investigate the influence of semi-purified (<b>SP</b>) and corn-soybean meal (<b>CSBM</b>) based diet types on the nitrogen-corrected ME (<b>ME<sub>n</sub></b>) of dextrose when determined by regression and to compare ME<i>n</i> values using the index and total excreta collection (<b>TC</b>) methods. The dextrose-associated caloric intake was regressed against the amount of dextrose intake to generate linear regression equations with slopes corresponding to the ME<i>n</i> value of dextrose within each basal type. The resulting dextrose ME<i> n</i> values determined using SP basal diets (3,502 and 3,553 kcal/kg) were similar (<i>P</i> > 0.05) to those determined using CSBM basal diets (3,839 and 3,588 kcal/kg) for index and TC procedures. In experiment 2, the influence of basal diet type on the ME and ME<i>n</i> values of an expeller-extruded soybean meal (<b>EE-SBM</b>) generated in broiler chicks using the regression method were evaluated. Linear regressions of EE-SBM associated ME<i>n</i> intake in kcal against EE-SBM intake in kg resulted in similar (<i>P</i> > 0.05) ME<i>n</i> values for SP (2,542 kcal/kg) and for CSBM (2,575 kcal/kg) diets. These results indicate that both total collection and index procedures may be reliably used to characterize the ME<i>n</i> content of feed ingredients, and that similar estimates of ingredient ME<i>n</i> can be determined in SP and CSBM diets, potentially allowing for simultaneous determination of ME and AA digestibility in a single study.</p><p>
|
|---|
