Phytate content of excreta and phytate retention in the gastrointestinal tract of young chickens

A HPLC procedure was used to determine inositol phosphate in chicken droppings and intestinal content. When compared with the classical ferric chloride method of determining total inositol phosphate in excreta, the HPLC method gave higher values, but the linear relationship between values determined by the two methods was significant (r = 0.82, P 0.014). Holding fecal samples at room temperature (22 C) from 0 to 32 h before analysis for inositol phosphates had no effect on the concentration of inositol hexaphosphate, and, although there were significant effects on inositol pentaphosphate, the results were difficult to interpret. The results indicated very little hydrolysis of inositol phosphate in the excreta of these chickens as they lay on a dropping tray. Excreta from 3-wk-old birds contained significantly less inositol pentaphosphate than excreta from 2-wk-old birds. The excreta from birds receiving a diet containing 0.27% nonphytate phosphorus contained less inositol pentaphosphate than those receiving a diet containing 0.42% nonphytate phosphorus. The chromic oxide indicator method seemed to be feasible for determining total phytate disappearance (retention). It was not satisfactory for determining retention in various sections of the gastrointestinal tract, because there seemed to be dilution of phytate and disappearance of chromic oxide in the crop and gizzard in the chicken. There was a marked increase in the concentration of inositol hexaphosphate and to a lesser extent inositol pentaphosphate in the small intestine and cloaca as the other nutrients in the diet were digested