Fermentation of soybean meal with Aspergillus usamii improves zinc availability in rats

Soybean meal was fermented with Aspergillus usamii to improve zinc availability through the degradation of phytic acid. Rats fed a diet containing fermented soybean meal showed greater femoral zinc than did animals fed a diet containing regular soybean meal. Zinc solubility in the small intestine was higher in the rats fed fermented soybean meal than in the rats fed regular soybean meal. These results suggested that fermentation with Aspergillus usamii improved zinc availability in dietary soybean meal, which was induced by the increase of zinc solubility in the small intestine. Adding the same amount of phytate that was contained in the regular soybean meal-based diet did not affect the amount of zinc present in rats fed a fermented soybean meal-based diet with sodium phytate. Phytase activity was found in fermented soybean meal, and this activity may degrade added phytate in fermented soybean meal-based diet.