NUTRITIONAL SIGNIFICANCE OF PHYTIC ACID AND PHYTASE

In the nutrition of monogastric animals phytate-P represents a poorly available source of phosphorus, especially in the case of diets low in phytase activity. Similarly the bioavailability of different minerals and trace elements is considerably reduced by phytate complexes. High concentrations of Ca increase the antinutritive effect of phytic acid on mineral and trace element bioavailability and thus impede the acti on of phytase. This effect can in part be compensated by an increased supply of vitamin D. There is also evidence for protective functions o f phytic acid such as the prevention of the formation of free radicals , the delaying of post prandial glucose absorption, the decrease in pl asma cholesterol and triglycerides as well as a change in the carry ov er of heavy metals. The basic mechanisms by which phytic acid may exer t these effects are still not clear. In several studies reported in th e literature, evidence for the nutritional significance and ecological importance of microbial phytase for pigs and poultry has been given. As the monogastric organism contains no or only negligible amounts of endogenous phytase in the stomach and small intestine, it is therefore dependent on plant or microbial phytase. Plant phytase, e.g. from rye , triticale, wheat or, in smaller amounts from barley, and supplemente d Aspergillus-phytase display cumulative effects.