Heat treatment of rapeseed meal increases phytate flow into the duodenum of sheep

The effect of heat treatment on duodenal flow of phytate, i.e., inositol hexaphosphate, from rapeseed meal was studied in four sheep fitted with duodenal cannula. The rapeseed meal was fed untreated, heated at 133°C (H133) or heated at 143°C (H143) for 3 h. Levels of phytate and its hydrolysis products, i.e., inositol tri-, tetra- and pentaphosphates were measured in duodenal digesta. Phytate was the major form of inositol phosphate (IP) in the duodenal digesta. Heat treatment increased daily flow of inositol hexaphosphate, inositol pentaphosphate, and inositol tetraphosphate into the duodenum. Approximately 22, 37 and 55% of dietary phosphorus in the form of IPs was recovered at the duodenum of sheep fed untreated, H133- and H143-treated rapeseed meals, respectively. s suggest that heat treatment of rapeseed meal increases flow of phytate into the duodenum, decreasing the digestibility of dietary phytate phosphorus for sheep.