Perennial ryegrass improves bone quality in geese: insights from the gut-bone axis.

Bone disorders are marked by leg deformities, and disruption in the gut microbiota have been associated with degradation of bone structure, which increases the susceptibility of fractures. Perennial ryegrass has antimicrobial, antioxidant and anti-inflammatory properties to improve bone health by regulating the gut microbiota. In this study, we investigated the anti-inflammatory potential of perennial ryegrass to modulate the inflammatory bone loss in meat geese through regulating gut microbiota. Perennial ryegrass (GD) significantly reduced (p < 0.05) the inflammatory response (IL-1β and TNF-α) by improving the gut barrier function. Perennial ryegrass (GD) improved tibia bone mineral density (BMD), ash% and tibia bone mineral contents (p < 0.05). Results of gut microbiota and micro-computed tomography analysis showed that the beneficial effect of GD on bone mass might be associated with higher relative abundance of short-chain fatty acids (SCFAs) producing gut microbiota in the cecum by improving microbial diversity as compared to commercial feeding (CD). Regarding bone turnover, GD increased bone formation markers such alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), osteoprotegerin (OPG), osteocalcin (OCN), mothers against decapentaplegic homolog (SMAD) expression by reducing the nuclear factor-kappa B (NF-κB) expression and bone resorption markers i.e. nuclear factor of activated T-cells, cytoplasmic 1 (NFATC1) and tumor necrosis factor receptor associated factor 6 (TRAF-6). Perennial ryegrass exhibited an increase in antioxidant potential by reducing the malondialdehyde (MDA) and reactive oxygen species (ROS) production leading to increased catalase (CAT) and glutathione per oxidase (GSH-PX) levels (P < 0.05). Western blot and Immunofluorescence analysis of tibia showed reduced expression of NF-κB in GD group. These results indicate the importance of perennial ryegrass in alleviating bone loss through gut microbiota via NF-κB signaling mechanism. These findings emphasize the significance of the gut-bone axis and offer new insights into the role of perennial ryegrass in promoting bone health.