Near infrared reflectance (NIR) spectroscopy to predict the metabolisable energy content in poultry feeds
Tyagi Pramod K.*, Shrivastav A.K., Tyagi Praveen K., Mandal A.B., Elangovan A.V.1
Central Avian Research Institute, Izatnagar - 243 122 (U.P.)
*Corresponding author: E-mail - firstname.lastname@example.org
1National Institute of Animal Nutrition and Physiology, Bangalore.
Near infrared reflectance analysis (NIR) spectroscopy technique was assessed to predict metabolizable energy (AME) values in complete poultry feeds. Sixty mixed feeds for layers, broilers, quails, guinea fowls, turkeys and ducks were formulated with various protein supplements of known AME values. The AME values ranged from 2546 to 3436 kcal/kg and were determined by bioassays conducted on adult cockerels. Cockerels employed for the bioassays were housed individually in metal cages with feeding, watering and excreta collection facilities. Six cockerels were randomly assigned to each experimental diet. A total of 60 bioassays were performed and each of these involved a 10-days adoption period followed by a 3-days collection period. Feed and faces samples were analyzed for gross energy using Auto Bomb calorimeter, nitrogen and dry matter and AME values was calculated. NIR reflectance spectra for all diets samples were recorded using Foss NIR System model 6500 Spectrophotometer and Intrasoft International (ISI) WINISI software. NIRS scanning was performed via a transport module in reflectance mode over the wavelength range of 400-2,500 nm at 2 nm intervals using a small ring cup. The accuracy of the calibration was assessed by the coefficients of determination (r2), standard error of the estimate (SEE), bias or mean difference between lab analysis and NIR predicted values. The r2 value between NIR and laboratory estimated AME was 0.895 (P<0.000). Range for lab and NIR AME values were 2546 to 3436 and 2641 to 3399 kcal/kg, respectively. Mean value and standard deviation for lab analysis vs NIR analysis was 2933, 2928 and 219.8, 210.9 respectively. The accuracy of predicting AME in poultry feed by using PCA (principal component analysis) was ±5%. The result indicated that lab AME values in the present study were appropriate and matched well with the predicted NIR values for AME. It can be concluded that near infrared reflectance analysis has a potential for measuring AME in complete poultry diets.
NIR spectroscopy, metabolizable energy, poultry feeds.