PURPOSE: Chronic high-fat diet (HFD) consumption results in gut dysbiosis, systemic inflammation, obese-insulin resistance, and osteoporosis of the jawbones. The probiotics, prebiotics or synbiotics alleviated gut dysbiosis and the metabolic disturbance in HFD-induced obesity. However, the effects on jawbone properties have not been investigated. This study aimed to investigate the effects of probiotic Lactobacillus paracasei HII01, prebiotic xylooligosaccharide (XOS), and synbiotics on the jawbone properties along with metabolic parameters, gut and systemic inflammation in HFD-fed rats. METHODS: Forty-eight male Wistar rats were fed with either a HFD or normal diet for 12 weeks. Rats in each group were subdivided into four subgroups to be treated with either vehicle, probiotics, prebiotics, or synbiotics for the additional 12 weeks. Blood samples, gut, bone marrows, and jawbones were collected to determine metabolic parameters, inflammation, and bone properties. RESULTS: The HFD-fed rats developed obese-insulin resistance, as indicated by increased body weight, dyslipidemia and decreased insulin sensitivity. Serum lipopolysaccharide levels and interleukin-6 mRNA expression in the ileum and bone marrows were elevated. Altered bone metabolism and the impaired jawbone properties were evident as indicated by decreased bone mineral density with increased trabecular separation. Reduced ultimate load and stiffness were observed in HFD-fed rats. Treatments with probiotics, prebiotics or synbiotics in HFD-fed rats improved metabolic parameters and reduced inflammation. However, no alterations in jawbone properties were found in all treatments. CONCLUSION: The osteoporosis of the jawbone occurred in obese-insulin resistance, and treatments with probiotics, prebiotics and synbiotics were not sufficient to improve the jawbone properties.