HYDROLYSIS OF PHYTATE AND INOSITOL TRI-PHOSPHATE, TETRA-PHOSPHATE, AND PENTA-PHOSPHATE BY THE INTESTINAL-MUCOSA OF THE PIG

Sodium phytate was hydrolysed and inositol phosphates with 3 to 6 phos phates (IP3, IP4, IP5 and IP6) were purified by column chromatography. Intestinal mucosal samples were prepared from 4 pigs and incubated wi th each of the inositol phosphates and hydrolysis estimated by measuri ng phosphate released at 37 degrees C over a 2 hr period. Optimal cond itions for the hydrolysis of IP3-IP6 were assessed by altering the sub strate concentrations, pH and the amount of added zinc and magnesium. The effects of these factors differed among the substrates. For all su bstrates, the jejunum had the highest activity. It was concluded that in the pig intestinal mucosa there was hydrolytic enzymic activity tow ards IP3-IP6, which decreased with increasing number of phosphate grou ps. Since microbial phytase is being added to some pig feeds, it is li kely that the lower inositol phosphates generated in the diet will be subjected to further hydrolysis in the intestine.