Protein quality and calcium availability from extruded and autoclaved turkey hatchery residue

Abstract

The protein quality of an extruded mixture of hatchery by-product meal and soybean meal (EHSM) and the calcium availability of autoclaved hatchery by-product meal (AHBM) were determined. In Experiments 1 and 2, EHSM or soybean meal (SBM) were the only protein sources in diets formulated to contain 16, 20, or 24% CP. In both experiments, there were five or six replicate pens randomly allotted to each level of dietary protein and each pen contained five poults. In Experiment 1, there was a significant increase in the Protein Efficiency Ratio (PER; P < or = 0.005) in poults from a fast-growing line compared with poults from a slow-growing line selected for egg production but no significant differences between EHSM and SBM. In Experiment 2, PER was increased in poults fed EHSM (P < or = 0.002). In both studies, there was a large decline in PER in those poults fed the 16% SBM diet, and this resulted in a significant source by level interaction. There were no significant source or level of protein effects on the Net Protein Ratio (NPR) or Net Protein Utilization (NPU) in Experiment 2. In Experiment 3, AHBM, steamed bone meal and limestone were the primary sources of calcium in diets containing 0.6, 0.8, 1.0, and 1.2% calcium. There were four replicate pens per level and source of calcium. The length and width of the femur and tibia were measured along with fat-extracted bone weight and ash. Poults fed diets containing AHBM and limestone had improved feed efficiency (P < or = 0.008) compared with those fed bone meal. There were no significant diet effects on any bone measurements.