In the research project, an ion chromatography technique was used as an alternative to microbiological assay to determine the content of myo-inositol in plant components of feeds. The analyzed material consisted of both genetically non-modified and modified varieties of wheat, corn, and soybean, as well as of feed mixtures made on the basis thereof. The contents of total and free inositol were determined as was the content of dialyzable inositol released by in vitro procedure to simulate the intestinal tract of broilers. The myo-inositol was separated on a high performance, anion-exchange CarboPack PA100 column, and determined using a pulsed amperometric detection procedure (i.e. high performance anion-exchange chromatography with pulse amperometric detection, HPAEC–PAD). The content of total inositol determined by the HPAEC–PAD method ranged between 2572 μg/g (corn-soybean feed) and 3667 μg/g (corn). The data obtained were comparable only with the results of the microbiological assay of both the genetically nonmodified and modified soybean pellets, (2392 and 2636 μg/g, respectively). As regards the other feed components, the results obtained by the HPAEC-PAD method were higher than those obtained using the microbiological method, on average: by 30 to 50 %. In the range of the concentration values from 0.1 to 100 μg/ml, a correlation between the two methods analyzed was the highest in the case of the analysis of myo-inositol released during the in vitro digestion procedure (r = 0.88). In all other cases, the results of the microbiological assay were systematically lower because the liberation of total inositol by the acid hydrolysis was incomplete, and S. cerevisiae ATCC 9080, the micro-organism analyzed, couldn’t utilize the inositol monophosphate to grow. The other possibility was a common presence of hydrophobic aminoacids in soy-containing components of feeds, which could interfere with the system of pulsed amperometric detection.
myo-inositol, myo-inositol phosphates, ion-chromatography, electrochemical detection