The use of near-infrared reflectance spectroscopy to predict the moisture, nitrogen, calcium, total phosphorus, gross energy, and phytate phosphorus contents of broiler excreta

One hundred forty-three broiler chick excreta samples were obtained from previous experiments dealing with phytate phosphorus utilization. The air-dried samples were ground in a Cyclotech 1093 sample mill and analyzed for the following: moisture, N, Ca, energy, total P, and phytate P. By chemical assay, the sample compositions were moisture: mean = 9.62, SD = 1.27% (range = 7.37-13.59); N: mean = 5.31, SD = 0.37% (range = 4.28 to 6.48); Ca: mean = 1.66, SD = 0.32% (range = 0.85 to 2.6); total P: mean = 1.13, SD = 0.28% (range = 0.66 to 1.75); gross energy: mean = 3,560, SD = 120 kcal/kg (range = 3,309 to 3,882); phytate P: mean = 0.63, SD = 0.17% (range = 0.32 to 0.97). The samples were scanned in a Feed & Forage Analyzer Model 5000 with near-infrared reflectance spectroscopy (NIRS)-2 Software. One hundred twenty-three samples were used to create the calibration curves (20 randomly selected samples were set aside for validating the calibration). The combination of math treatments and scatter corrections that provided the best standard error of cross validation (and its correlation coefficient) was chosen for the standard curves. The coefficients of determination (R2) were moisture, 0.96; N, 0.88; Ca, 0.84; total P, 0.91; gross energy, 0.86; and phytate P, 0.86. The standard errors of prediction were moisture, 0.342%; N, 0.193%; Ca, 0.143%; total P, 0.134%; gross energy, 74.66 kcal; and phytate P, 0.91%. We concluded that it is possible to predict the moisture, N, Ca, gross energy, total P, and phytate P in broiler excreta by using NIRS.