COMPARATIVE-STUDY OF PHOSPHORUS UTILIZATION FROM WHEAT, BARLEY AND CORN DIETS BY YOUNG-RATS AND PIGS

A 3-week experiment using 36 growing male rats (97 g) and a 4-week experiment using 18 castrated growing male pigs (16 kg) were carried out to compare the ability of both species to utilize phosphorus from wheat, barley and corn diets. The animals were allotted to treatment groups. The experimental diets contained the same amounts of calcium (0.51-0.52%), phytate phosphorus (0.19-0.20%) and total phosphorus (0.33-0.35%), the latter at a marginal deficient level. In rats similar rates of apparent absorption and utilization of phosphorus were found for all three cereals diets. Pigs on the wheat diet absorbed the phosphorus as effectively as the rats but utilization was significantly lower. The animals in the barley and especially the corn group absorbed and utilized the total phosphorus at a significant lower rate. The better absorption of cereal phosphorus by the rats is mainly due to the significant higher phytate breakdown in the stomach and the small intestine. Together with some other aspects known from the literature the results are discussed in context with the higher pH values in the stomach and the slower food passage rates in the stomach and small intestine of the rats.