Phosphorus Measurements in Feed Ingredients

Phosphorus in feed ingredients contributes to meeting nutrient needs and environmental concerns. The two objectives of this study were to measure phytic phosphorus in relation to the total phosphorus in a range of ingredients and to investigate the ability of near infrared spectroscopy (NIRS) to analyze for total and phytic phosphorus in feed ingredients. A total of 227 samples mainly representing cereals, cereals by-products, oilseeds and oil meals were collected worldwide during one year. All samples were analyzed for their concentrations in total and phytic phosphorus using mineralization and enzymatic methods, respectively. These samples were also analyzed for their absorbances from 1100 to 2500 nm using NIRS equipment. For all the analyzed samples, prediction models were then calculated to determine correlation between absorbances to total and phytic phosphorus, using mPLS regression.

The results indicated that phytic phosphorus content ranged from 18% (cassava) to 83% (rice bran) of the total phosphorus content. There were also large variations intra-species in the ratio phytic phosphorus/ total phosphorus (and corresponding concentrations in phytic phosphorus in % as fed) which ranged from 64 to 87% (0.14-0.30) in corn lots, from 64 to 80% (0.16-0.27) in wheat samples, from 66 to 95% (0.54-0.98) in rapeseed meals, and from 59 to 69% (0.36-0.57%) in soybean meals. Prediction models developed using NIRS explained 93 and 92% of the variations measured in total and phytic phosphorus with standard error of 0.05 and 0.04%. This study confirmed the need for accurate assessment of nonphytic phosphorus analytical values for major feed ingredients in formulating feeds. With respect to the range measured among ingredients. The feasibility study using NIRS to monitor total and nonphytic phosphorus levels in feed ingredients was demonstrated in this study

Gady, C. and co-workers. 2010. Predicting variations in total and phytic phosphorus in raw materials of plant origin. J. Animal Sci. 88: E-Supplement 2; Abstract 1113 on page 863.