The use of near infrared reflectance spectroscopy (NIRS) for the chemical analysis of meat and feedstuffs

[摘要] ENGLISH ABSTRACT: Near infrared reflectance spectroscopy (NIRS) was evaluated as a tool to predict the chemicalcomposition of ostrich meat, mutton and feedstuffs. Seventy-three calibrations were developed. NIRSanalyses were conducted on an InfraAlyzer 500 spectrophotometer between 1100 and 2500 nm wavelengths.Near infrared reflectance calibrations were developed for (i) the proximate chemical composition ofostrich meat; (ii) the proximate chemical and mineral composition of mutton; (iii) the chemical compositionand digestibility of lupins, full-fat canola and the determination of alkaloids in lupins; (iv) the chemicalcomposition and digestibility of winter grains and maize; (v) the chemical composition and digestibility ofcereal hay, cereal straw, wheat stubble and alfalfa-grass/hay mixtures. The chemical composition ofdifferent types of winter grain produced in the Western Cape area of South Africa, as well as the chemicalcomposition and digestibility of winter grain hay and straw produced in a Mediterranean rainfall area werealso determined.Near infrared reflectance spectrometry proved to be successful for the prediction of crude protein (CP)and fat in both animal species, as well as for ash and dry matter (DM) in freeze-dried mutton. Accuratecalibrations were also developed for certain minerals (K, P, Na, Mg, Fe and Zn).Calibrations proved to be accurate for all the relevant chemical constituents in lupins, as well as theDM, CP and fat calibrations in full-fat canola. The alkaloid calibration showed potential although moresamples should be included for a more accurate calibration. Winter grain calibrations were accurate for fat,acid detergent fibre (ADF), in vitro organic matter digestibility (IVOMD), lysine and methionine. Allchemical composition calibrations of maize, except for ash, were accurate for future prediction. Chemicalcomposition calibrations of wheat stubble and alfalfa-grass hay mixtures resulted in prediction with similaror slightly higher accuracy than calibrations reported in the literature. The calibrations developed for cerealhay and straw were not suitable for prediction purposes. Possible reasons were discussed to explain theseinaccurate calibrations. Variation shown between different types of cereal grain (2-row barley, 6-row barley, oats, wheat andtriticale) accentuated the need for the analysis of different batches of grain produced under differentconditions for use in animal feed. The chemical composition and digestibility of winter grain straw and haywere also obtained. These values provide a database for calculation of inclusion levels of these feedstuffs inanimal diets.These investigations showed the NIRS to be a successful and rapid tool for the prediction of thechemical composition of ostrich and lamb meat and locally produced feedstuffs.

[发布机构] Stellenbosch University