Abstract: An experiment was conducted by using 300 New Yangzhou Layers aged 58 weeks to study the effect ofphosphorus level on parathyroid element (PTH), fall calcium element (CT), estradiol (E2), bone calcium element(BGP)and bone density (BMD)of old layers.Layers were randomly divided into three treatments (control group,0.25% treatment and 0.15% treatment), each treatment represented by five replicates.Layers were fed corn -soybeanbased diet with different levels of the effective phosphorus:0.35%, 0.25% and 0.15%.The results showed that the difference of PTH and CT in each group was not remarkable;E2 and BMD of 0.15%treatment was obviously lower than that of the control group (p <0.01);while BGP of 0.15% treatment was remarkable higher than that of the controlgroup (p <0.01).Conclusion:Osteoporosis morbidity of old layers increases along with reducing phosphorus level.Theeffective phosphorus level is 0.35% is helpful to the postponement old layers sclerotin outflow, while the effective phosphoruscontent is lower than 0.15%, then it can obviously elevate BGP, reduce the E2 level,and the sclerotin outflow becoming severity.

Key words: Phosphorus, Layers, Endocrine, Bone density, Osteoporosis

CLC Number: 

• S831