Insights into the Osteoprotective Potential of Chemically Modified Natural Polysaccharides for Animal Skeletal Health: A Narrative Review

In intensive livestock production, the imbalance between rapid muscle accretion and insufficient skeletal mineralization predisposes animals to skeletal disorders, threatening production efficiency and animal welfare. Natural polysaccharides demonstrate osteoprotective potential, yet their in vivo application is largely limited by high molecular weight, low solubility, and poor bone-targeting capacity. Strategies involving chemical modification can overcome these limitations by enhancing endogenous osteogenic bioactivity and, in some cases, introducing functional groups that confer osteoinductive functions. This review highlights recent advances in chemically modified polysaccharides for promoting animal bone health and systematically dissects their dual protective mechanisms. Their direct effects include regulating osteoblast differentiation, inhibiting aberrant osteoclast activation, accelerating microvascular angiogenesis, and facilitating bone matrix biomineralization. Meanwhile, indirect effects encompass alleviating oxidative stress, reshaping gut microbiota and metabolites, and balancing the skeletal immune microenvironment. Recent evidence and remaining challenges are also summarized, providing a theoretical foundation for functionalized polysaccharides to support bone health in commercial animal husbandry.