By adding prebiotics and growth factors,Lctobacillus rhamnosus was used to ferment bovine bone to promote calcium transformation.After single-factor experiments,prebiotics and growth factors were screened and the amount of addition was tested.Using response surface experimental design,the combination of prebiotics,amino acids and vitamins for LGG was optimized based on calcium conversion rate.The results showed that sugars have the higher impact on calcium conversion than amino acids,while Vitamins have the least impact.The optimized conditions for Lactobacillus rhamnosus fermentation of cattle bone meal were nicotinic acid∶ Vitamin B2=2.82∶ 1,arginine∶ Met=1.82∶ 1,glucose∶ Isomaltooligosaccharide=3.80∶ 1,inoculum size 3%,fermentation temperature 37℃,shaking speed 100 r/min,and fermentation time 72 h.Under these conditions,the conversion rate of calcium was 28.32%.