摘要This study aimed to determine the effects of 25-hydroxyvitamin D3(25-OH-VD3),combined with chondroitin sulfate(CS)and glucosamine sulfate(GS),on calcium and phosphorus metabolism and bone development of weaned piglets.One hundred weaned piglets(28 d old;Duroc × Landrace × Large White;initial body weight,7.8±0.22 kg)were randomly assigned to 5 dietary treatments,which included basal diet+50 μg/kg vitamin D3(CON),basal diet+50 μg/kg 25-OH-VD3(HyD),basal diet+50 μg/kg 25-OH-VD3+800 mg/kg CS(CS),basal diet+50 μg/kg 25-OH-VD3+1200 mg/kg GS(GS),and basal diet+50 μg/kg 25-OH-VD3+800 mg/kg CS+1200 mg/kg GS(CS+GS).The experiment lasted 31 d,including 3 d of acclimation.The results showed that pigs in the HyD and GS groups had a higher(P=0.006)apparent digestibility of calcium than pigs in the CON group.The bone mineral density and calcium content in the metatarsal and phalangeal bones of piglets in the CS and GS groups were significantly higher(P＜0.05)than those in the CON and HyD groups.The mRNA expression of transient receptor potential cation channel subfamily V member 6 and calcium-binding protein D9K in the colon mucosa and transient receptor potential cation channel subfamily V member 5,solute carrier family 34 member 1,calcium-sensing receptor,and calcium-binding protein D28K in the kidneys of piglets was upregulated(P＜0.05)in the GS group compared to that in the CON,HyD,CS,and CS+GS groups.The protein expression of cytochrome P450 27B1 and calcium-sensing receptor in the kidneys of piglets was upregulated(P＜0.05)in the GS group compared to that in the CON,HyD,and CS+GS groups.Overall,dietary supplementation with 25-OH-VD3 alone or in combination with GS enhanced bone development in piglets by improving calcium and phosphorus metabolism.