Regulation of bone phosphorus retention and bone development possibly by BMP and MAPK signaling pathways in broilers

The bone morphogenetic protein(BMP)and mitogen-activated protein kinase(MAPK)signaling pathways play an important role in regulation of bone formation and development,however,it remains unclear that the effect of dietary different levels of non-phytate phosphorus(NPP)on these signaling pathways and their correlations with bone phosphorus(P)retention and bone development in broilers.Therefore,this experiment was conducted to investigate the effect of dietary P supplementation on BMP and MAPK signaling pathways and their correlations with bone P retention and bone development in broilers.A total of 800 one-day-old Arbor Acres male broilers were randomly allotted to 1 of 5 treatments with 8 replicates in a completely randomized design.The 5 treatments of dietary NPP levels were 0.15,0.25,0.35,0.45 and 0.55%or 0.15,0.22,0.29,0.36 and 0.43%for broilers from 1 to 21 days of age or 22 to 42 days of age,respectively.The results showed that extracellular signal-regulated kinase 1(ERK1)mRNA expression in the tibia of broilers on days 14 and 28,phosphorylated-ERK1(p-ERK1)on day 14,and BMP2 protein expression on days 28 and42 decreased linearly(P<0.04),while c-Jun N-terminal kinase 1(JNK1)mRNA expression on day 42 increased linearly(P<0.02)with the increase of dietary NPP level.At 14 days of age,total P accumulation in tibia ash(TP),bone mineral concentration(BMC),bone mineral density(BMD),bone breaking strength(BBS)and tibia ash were negatively correlated(r=-0.726 to-0.359,P<0.05)with ERK1 and JNK1 mRNA as well as p-ERK1;tibia alkaline phosphatase(ALP)and bone gal protein(BGP)were positively correlated(r=0.405 to 0.665,P<0.01)with ERK1 mRNA and p-ERK1.At 28 days of age,TP,BMC,BMD,BBS and tibia ash were negatively correlated(r=-0.518 to-0.370,P<0.05)with ERK1 mRNA and BMP2 protein,while tibia ALP was positively correlated(r=0.382 to 0.648,P<0.05)with them.The results indicated that TP,BMC,BMD,BBS or tibia ash had negative correlations,while tibia ALP and BGP had positive correlations with ERK1 and JNK1 mRNAs,BMP2 protein and p-ERK1,suggesting that bone P retention and bone development might be regulated by BMP and MAPK signaling pathways in broiler chickens.

Long-Term Animal Feeding Trial of the Refined Konjac Meal Ⅰ. Effects of the Refined Konjac Meal on the Calcium and Phosphorus Metabolism and the Bone in Rat

Effects of refined konjac meal (RKM) on the calcium and phosphorus metabolism and bone parameters were observed in rats of both sexes fed with food containing 1% of RKM for 18 months. A comparable group of rats fed on basic diet only was used as a control.Results obtained indicate that all the measured parameters (serum calcium and phosphorus level, femur weight and its calcium and phesphorus content, and the osteometry of the tibia) showed no significant difference between the experimental and the control groups.Thus there is no adverse effect either on the calcium and phosphorus metabolism or on the bone after a long-term intake at a moderate dosage.