Determination and prediction of standardized ileal amino acid digestibility of wheat shorts for pullets during the brooding and growing phases

Objective: This study was conducted to evaluate the nutritional value of ten wheat shorts (WS) originating from different regions by determining their standardized ileal digestibility of amino acids (SID AA) in pullets during the brooding (d 28-31) and growing (d 92-95) phases, and to establish SID AA prediction equations based on their chemical composition.Methods: A total of 990 pullets were used, with 594 in the brooding phase and 396 in the growing phase.In each phase, birds were randomly assigned to one of 11 dietary treatments, including one nitrogen-free diet and ten test diets each formulated with an individual WS sample as the sole protein source.All diets contained 0.5% titanium dioxide as an indigestible marker.Results: Substantial variation (CV > 10%) was observed in ether extract, crude ash, crude fiber, acid detergent fiber (ADF), neutral detergent fiber, and total starch (TS) among the WS samples.During the brooding phase, SID was lowest for cysteine (74.10%) and highest for glutamic acid (90.06%).During the growing phase, cysteine was again lowest (70.33%) and glutamic acid highest (90.22%).Except for tryptophan, the WS source significantly affected SID AA (p<0.05).In the brooding phase, ADF, TS, and gross energy (GE) were identified as significant predictors of SID AA.Similarly, ADF and GE were reliable predictors in the growing phase. Conclusion:Considerable variation was observed in the chemical composition of WS from different origins, and the origin had a significant effect on SID AA.During the brooding phase, the equation with the highest R² was SID Met = 51.929+1.015TS-0.494NDF(R² = 0.976; p<0.001).During the growing phase, the equation with the highest R² was SID His = -511.489-2.095ADF+23.722GE+1.652NFE(R² = 0.900; p<0.001).