Abstract: Glycerol monolaurate (GML) possesses excellent emulsifying and antibacterial properties as a functional food ingredient. To investigate its potential in the development of a dietary supplement for promoting osteogenesis and preventing osteoporosis, a growing rat model was used in this study. The effect of 750 mg/kg GML supplementation on bone growth and morphology in rats was assessed. The mechanism of action of GML in promoting bone growth in rats was explored by analysis of biochemical indexes, the intestinal microbiome and microbiota-related metabolites. The results showed that dietary supplementation of 750 mg/kg GML did not significantly affect the basal growth indexes such as body mass, food intake and organ coefficients, but significantly increased the bone growth indexes such as tibia length and index and enhanced the biomechanical properties of femur while not causing structural degeneration of cancellous or cortical bone. Dietary supplementation of GML significantly increased the serum bone metabolism indexes such as growth hormone, insulin-like growth factor 1 and transforming growth factor β1, which promote bone formation. Compared with the control group, GML treatment improved the composition of the intestinal flora, significantly increased the relative abundance of beneficial bacteria such as Prevotellaceae_UCG-001, and increased the concentrations of fecal short-chain fatty acids such as acetic acid and propionic acid. In conclusion, GML can promote bone formation by increasing the levels of serum hormones and cytokines related to bone formation, or indirectly improve bone growth by improving the composition of the intestinal flora and promoting the production of fecal short-chain fatty acids. The results of this study provide a theoretical basis and application example for GML as a dietary supplement in the development of functional food for improving bone growth.

Key words: glycerol monolaurate; growing rats; bone growth; gut microbiota; short-chain fatty acids