(P11-014-23) Microbiome Analysis From Small Intestines of Mice Fed With Zinc Supplement and Phytic Acid

Objectives: Phytic acid (Inositol hexaphosphate; IP6) is a potent inhibitor of zinc absorption with its high cation-binding capacity to zinc. As IP6 is degraded into inositol with the lower number of phosphates (IP) and myo-inositol (MI) by microbial phytase, microbiota residing in the small intestine was raised as a potential factor contributing to zinc absorption. We thus aimed to investigate how small intestine microbiota is related to IP6 degradation and zinc absorption.

Methods: 5 groups of C57BL/6 mice were fed control diet, zinc-containing diet, zinc-containing diet with IP6, zinc-containing diet with low concentration MI, and zinc-containing diet with high concentration MI. The zinc contents in diets were equivalent to human supplementary dose and IP6 and high concentration MI content followed the PZMR (phytate:zinc molar ratio) of 20:1, presuming low concentration MI supplementation reflects less degradation of IP into MI. Serum zinc was quantified via colorimetric assay. Microbial DNAs from duodenum, jejunum and ileum of small intestines were extracted and 16S ribosomal RNA sequencing was conducted targeting V3-V4 region. The sequencing results were treated using QIIME2 Pipeline, and microbiome analysis was performed on MicrobiomeAnalyst platform.

Results: The small intestine microbiome showed significant changes in populations among 5 diet groups and moderate changes in different intestine segments. Differences between control and all zinc-supplementation groups showed the increased relative family abundance of Erysipelotrichales and the decreased abundance of Bifidobacteriaceae. Among genera with significant effect sizes, the population of Dubosiella was induced in the group fed with only zinc, which was reduced to basal abundances upon IP6 or MI supplementation. Also, the abundance of Faecalibaculum genus increased by specifically IP6 supplementation but by none of MI supplementation.

Conclusions: Small intestine microbiome structures in mice were altered by the zinc supplement in diets. The abundance of Faecalibaculum especially increased in the zinc plus IP6-fed mice, suggesting its potential role in IP6 utilization in the condition of zinc supplementation in small intestines.

Funding Sources: United States Department of Agriculture