Summary

The on-going usefulness of AusScan AME calibrations will require periodic update with additional mainstream cereal grains (wheat, sorghum, triticale and barley) with differing agronomic properties from widespread growing sites in Australia and across harvest years.
Robustness of the calibrations refers to their capacity to predict accurately the AME values of ‘unknown’ samples not used previously in development of the calibrations. Because there have been no ‘new season’ grains evaluated to date, the robustness of calibrations would be greatly enhanced by addition of new seasons wheat grains which would be measured soon after harvest and again later in the year to assess post-harvest effects. These results would enhance both the ‘global’ calibrations (where all grains were used to establish the calibration) and the single-grain calibration for wheat.
The latest AusScan calibrations include a response to enzyme effect on AME. This was based on only one xylanase product in combination with a single phytase product used for all cereal grain types. The usefulness of the NIR calibration to predict enzyme uplift would be assessed in a pilot study to determine whether a single NIR calibration was sufficient or whether different types of xylanase required separate calibrations.
Finally, data underpinning the AusScan NIR calibrations show that male and female chickens can respond quite differently. The question arises “Does NIR predict AME equally well for males and females”? This question could be addressed at relatively modest cost by re-evaluation of existing data without need for further experimentation at this stage.

Program

Chicken Meat

Research Organisation

Minister for Primary Industries and Regional Development acting through the South Australian Research and Development Institute

Objective Summary

Objective 1 – Determine whether NIR predicts AME and AME intake index equally well for both genders by re-evaluation of existing data underpinning the AusScan calibrations.
Objective 2 – Measure broiler AME and AME intake index for 8 new season wheat samples within one month of harvest from four widely separated geographic regions shown previously to produce grain differing widely in AME. Repeat these measurements at 4 and 10 months post-harvest to evaluate new season grain effects and responses to a combination of xylanase and phytase enzyme products.
Objective 3 – Compare responses of Ross and Cobb broilers fed a subset of 6 wheat samples sourced from industry. Use 2 different combinations of enzyme products and compare these results with NIR-predicted AME values.
Objective 4 – Update the AusScan NIR calibrations with 24 cereal grain samples sourced from industry, and fed with and without a combination of xylanase and phytase enzymes.