Sialoglycoprotein isolated from the eggs of Carassius auratus prevents bone loss: an effect associated with the regulation of gut microbiota in ovariectomized rats.

The anti-osteoporotic effect of sialoglycoprotein isolated from the eggs of Carassius auratus (Ca-SGP) has previously been demonstrated in vivo. However, the mechanism by which this macromolecular substance regulates bone metabolism remains unclear. Given the correlation between gut microbiota and the homeostasis of bone metabolism, the current study applied real-time PCR and 16S rRNA high-throughput sequencing to investigate the influence of Ca-SGP on gut microbiota in ovariectomized rats. Real-time PCR analysis showed that Ca-SGP treatment significantly reversed the increase of Escherichia coli and Bacteroides fragilis, and the decrease of Clostridium leptum, Faecalibacterium prausnitzii, and Lactobacillus induced by ovariectomy. Subsequent high-throughput sequencing of 16S rRNA further demonstrated that Ca-SGP not only partly recovered the alterations of gut microbiota to baseline levels in OVX rats, but also significantly increased the relative abundance of Lactobacillus, which may support the protection of bone metabolism. The present study may contribute towards our understanding of the mechanism by which Ca-SGP seemingly preserves bone mass.