Analysis And Estimate Of Corn CNCPS Component By Near Infrared Reflectance (NIR) Spectroscopy

The objective of this study was to investigate the feasibility of predicting the CNCPS composition of corn by near infrared reflectance spectroscopy. Sixty-five corn samples from Heilongjiang province were used. The partial least square (PLS) regression method, second derivative and Norris derivative filter were applied in the NIRS prediction of CNCPS.Estimate of com conventional compositions: For Dry matter, Crude Protein, Ash, Fat, Starch, Neutral-detergent Fiber and Acid-detergent Fiber, the determination coefficients were 0.9743, 0.9683, 0.9478, 0.9098, 0.9777, 0.9354 and 0.9269, and the SD/RMSEP values for them were 3.96, 4.78, 3.75, 4.25, 4.13, 3.88 and 3.12, respectively. The determination coefficient and SD/RMSEP value were 0.8575 and 3.06 for soluble protein, but low determination coefficients of 0.5319 and 0.6833 with SD/RMSEP values of 5.50 and 2.85 were observed for acid-detergent insoluble protein and neutral-detergent insoluble protein.Crude protein is partitioned into five fractions in CNCPS. Fraction A is NPN (PA); Fraction C is unavailable or protein to cell wall (PC); Fraction B₂ is true protein with an intermediate degradation rate (PB₂); Fraction B₁ is rapidly degraded true protein (PB₁); Fraction B₃ is slowly degraded true protein (PB₃). the determination coefficients were 0.57,0.15,0.34,0.71 and 0.53, respectively. The SD/RMSEP value were 3.52,3.25,5.75,3.12 and 3.24, respectively.Carbohydrates can then be classified according to degradation rate in CNCPS system. Fraction A is fast and is sugars (CA); Fraction B₁ is intermediate and is starch (CB₁); Fraction B₂ is slow and is available cell wall (CB₂); and Fraction C is unavailable cell wall (CC). the determination coefficients were 0.38,0.35,0.12 and 0.15, respectively. The SD/RMSEP value were 2.08,3.22,0.45 and 0.22, respectively. the total carbohydrate (CHO) content in the feedstuff can be estimated (100 - CP - fat - ash), the determination coefficients and the SD/RMSEP value were 0.84 and 3.83, respectively. Nonstructural carbohydrate (NSC) was estimated by NIRS. The determination coefficients and the SD/RMSEP value were 0.83 and 3.69, respectively.The results of this study indicated that corn nutritive values could be fast and accurately predicted by NIRS. However, this model of ADL, ADIP and NDIP need improve further. The total CP of corn could be quite accurately estimated by NIRS technology. But probably as a consequence of the accumulative errors concerning the different laboratory procedures involved, NIRS technology did not provide accurate estimations of the five CNCPS fractions. As well, the total CHO and NSC of corn could be quite accurately estimated by NIRS technology. However, NIRS technology did not provide accurate estimations of the four CNCPS fractions.