Effect of Phytase on in Vitro Hydrolysis of Phytate and the Formation of myo-Inositol Phosphate Esters in Various Feed Materials

• Published in: Journal of agricultural and food chemistry Vol. 67; no. 41; pp. 11396 - 11402
• Main Authors: Hirvonen, Johanna, Liljavirta, Jenni, Saarinen, Markku T, Lehtinen, Markus J, Ahonen, Ilmari, Nurminen, Päivi
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 16.10.2019
• Subjects: 6-Phytase - chemistry; 6-Phytase - metabolism; Animal Feed - analysis; Animals; Bacterial Proteins - chemistry; Bacterial Proteins - metabolism; Chickens; Digestion; Enterobacteriaceae - enzymology; Esters - chemistry; Esters - metabolism; Food Additives - chemistry; Food Additives - metabolism; Gastrointestinal Tract - metabolism; Glycine max - chemistry; Glycine max - metabolism; Hydrolysis; Inositol Phosphates - chemistry; Inositol Phosphates - metabolism; Models, Biological; Phytic Acid - chemistry; Phytic Acid - metabolism; Zea mays - chemistry; Zea mays - metabolism; phytase; in vitro digestion model of poultry gastrointestinal tract; myo-inositol phosphate; phytate hydrolysis; myo-inositol
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/acs.jafc.9b03919

Phytase is commonly used as a feed enzyme in monogastric animals to increase the bioavailability of phytate phosphorus and other nutrients. The accumulation of myo-inositol phosphate intermediates during phytate degradation in various segments of the gastrointestinal tract (GIT) is poorly understood. The aim of this study was to determine the efficacy of Buttiauxella spp. phytase in degrading the phytate in corn, soybean meal, and complete corn–soybean meal diet to myo-inositol phosphate esters (IP1–IP5) and completely dephosphorylated myo-inositol rings using an in vitro model of the poultry upper GIT. Our results show that the phytase hydrolyzes phytate efficiently to small IP esters, whereas the myo-inositol level remains constant between control and phytase treatments. Although the in vitro digestion model does not incorporate all factors that govern phytate hydrolysis, it is a valuable tool for evaluating phytase efficacy at various enzyme doses and with different feed ingredients.