The possibilities of near infrared reflection spectroscopy to predict total-phosphorus, phytate-phosphorus and phytase activity in vegetable feedstuffs

Abstract

238 samples, representing 19 vegetable feeds, were analysed for total and phytate phosphorus. Phytase activity was estimated in a limited number of feeds with an activity of >100 units/kg. Near infrared reflection spectra (NIRS) were taken between 1100 and 2500 nm in steps of 4 nm. By means of principal component analysis the feeds were grouped in starch- (n = 150) and protein-rich feeds (n = 88). NIRS-calibrations were developed using partial least square regression and tested by cross-validation. Total P varied from 0.22 to 1.25% and phytate P from 0.05 to 1.02% for high-starch feeds and, respectively, from 0.46 to 1.37% and from 0.22 to 0.56% for protein-rich feeds. Within these broad ranges, NIRS-values were highly correlated to measured total and phytate P with prediction errors of 0.08 and 0.08%, respectively, for high-starch feeds and 0.08 and 0.04%, for protein-rich feeds. However, considering the mostly small deviation of mean or calculated values for the individual feeds, NIRS is practical for predicting total P for wheat byproducts and phytate P for maize gluten feed. On the other hand, NIRS could be used for unknown or not tabulated products. Spectral signals from total and phytate P are partly based on direct responses from organic complexes but also on secondary relations through protein and fat. It was concluded that NIRS seemed not sensitive enough to detect phytase.

Review: Near Infrared Spectroscopy of Faeces to Evaluate the Nutrition and Physiology of Herbivores

“…Since phytate p is generally not digested by monogastric animals such as pigs and poultry, measurement of both phytate p and total p is important for the nutrition of these species. calibrations for both total p and phytate p in plant feedstuffs 86 and in poultry excreta 60 have been reported, suggesting that nIr spectroscopy can be developed to measure both of these components of p in the faeces of monogastrics. However, since there are high correlations between the concentrations of phytate p and total p in at least some feedstuffs, 87 further investigation is required of the circumstances where these p fractions can be determined independently.…”

Prediction of Composition of Broiler Chicken Excreta Using Near-infrared Reflectance Spectroscopy

“…Studies have shown that Ca and P may exist in forms detectable by NIRS, at least in some grasses and legumes (Clark et al, 1987;Saiga et al, 1989). The calibration values obtained for P in forages were found to be acceptable by Clark et al (1987) but were not acceptable in similar studies by Vasquez Aldana et al (1995). De Boever et al (1994 reported that P of feedstuffs could be predicted by NIRS with an R 2 of 0.94 to 0.96 and SEP of 0.08.…”

“…They obtained an R 2 of 0.86, an SEP of 0.14 for Ca and R 2 0.93 and an SEP of 0.13 for P. They concluded that NIRS was a good predictor for Ca and total P content of chick excreta. There are no absorption bands for minerals in the near-infrared region, but organic complexes and chelates may still be detected (De Boever et al, 1994). Studies have shown that Ca and P may exist in forms detectable by NIRS, at least in some grasses and legumes (Clark et al, 1987;Saiga et al, 1989).…”

“…Near-infrared reflectance spectroscopy (NIRS) has been widely used as a rapid and accurate method for measuring some constituents of materials without requiring extensive sample preparation (Norris et al, 1976). Components successfully measured include nitrogen, moisture, fibre, starch, individual sugar, amino acids, and fat (Foley et al, 1998;Fontaine et al, 2002;Smith et al, 2001;Valdes and Summers, 1986), The principle of NIRS is the selective absorption of electromagnetic radiation from 800 to 2500 nm in accordance with the characteristic vibration frequencies of functional groups (De Boever et al, 1994). It has the capability to measure CH, NH, OH bonds, which form the functional groups in moisture, protein, amino acids, fibre, sugar and fat in biological samples.…”

“…Although organic complexes may be detected (Shenk et al, 1992), no absorption bands for minerals exist in the near-infrared region. Every biological substance has a unique NIRS composite spectrum, depending on their characteristic functional groups; the NIRS spectrum of a sample is the composition of all the physical and chemical information of the sample (De Boever et al, 1994;Murray and Williams, 1987).…”