Effects of Supplementary Genistein on Bone Development in Hy-Line Brown Pullets

Skeletal deterioration is a major welfare and production concern in laying hens, as substantial quantities of calcium are mobilized from bone to support eggshell formation during the laying cycle. Nutritional strategies that promote skeletal development during the pullet phase may therefore improve bone integrity later in production. The objective of this study was to evaluate the effects of dietary genistein supplementation on growth performance, bone development, and mineralization in Hy-Line Brown pullets. A total of 600 pullets were randomly assigned to four dietary treatments consisting of a control diet (0 mg/kg genistein; CON) or diets supplemented with 20 (G20), 60 (G60), or 100 mg/kg (G100) genistein from 5 to 17 weeks of age. Growth performance, bone mineral density, muscle deposition, biomechanical strength, bone ash content, and circulating bone formation biomarkers were evaluated. Pullets receiving G60 and G100 supplementation exhibited greater body weight, bone mineral density, cortical bone area, muscle weights, biomechanical strength, bone ash percentage, and circulating concentrations of BALP and P1NP compared with CON and G20 birds. Feed intake did not differ among treatments. These findings indicate that genistein supplementation, particularly at 60 and 100 mg/kg, may enhance skeletal development during the pullet rearing period. Further research is warranted to determine whether these improvements persist throughout the laying cycle and influence production, as well as the potential deposition of genistein-derived compounds in eggs.