Rapid weight gain as a factor compromising tibial health via the gut‒bone axis in broiler chickens

Rapid weight gain in broilers not only satisfies the high demand for high-quality protein in the growing market but also shortens the breeding cycle, thereby increasing production efficiency. However, this rapid growth is associated with several adverse effects on broilers, including metabolic abnormalities, increased cardiorespiratory burden, impaired bone and muscle development, compromised leg health, and even impaired flavor and taste. In this study, we aimed to investigate the associations among rapid weight gain, tibial health, and the gut–bone axis by using 300 broilers raised in a controlled growth environment for 21 days. The results indicated that rapid weight gain was associated with impaired tibial health in broilers, as evidenced by alterations in bone-related indicators, multiple histomorphological observations, and dysregulation of the RANKL/RANK/OPG signaling pathway. Transcriptomic analysis identified focal adhesion as a key pathway associated with tibial growth, accompanied by downregulation of the FAK/PI3K/Akt signaling pathway. This impairment was associated with significant changes in the structure and composition of the cecal gut microbiota in broilers, particularly those involving Ligilactobacillus (L.) aviarius_B , L. salivarius , and Limosilactobacillus reuteri . These changes are associated with modifications in blood metabolites crucial for bile acids, such as hyodeoxycholic acid and chenodeoxycholic acid, which are negatively correlated with tibial development. In summary, our findings highlight that rapid weight gain is associated with alterations in the gut–bone axis that may contribute to impaired tibial health in broilers, providing new insights for the management of bone health in poultry.