Tibial Bone Strength Research Articles

Moderate to vigorous physical activity and impact loading independently predict variance in bone strength at the tibia but not at the radius in children.

The objectives of this study were (i) to assess whether daily minutes of moderate to vigorous physical activity (MVPA) or vigorous physical activity (VPA) and impact counts (acceleration peaks ≥3.9g) independently predict variance in bone strength in children and youth and (ii) to estimate bone strength gain associated with increases in daily MVPA, VPA, or impact counts. We recorded 7-day activity of 49 participants (mean age 11.0 years, SD 1.7) using accelerometers and estimated radius and tibia bone strength using peripheral quantitative computed tomography. We used linear regression models adjusted for sex, body mass, and muscle area to address our objectives. Daily MVPA (mean 50 min, SD 23) and VPA (mean 17 min, SD 11) or impacts (mean 71 counts, SD 59) did not predict variance in radius strength. Daily VPA (β = 0.24) predicted variance in tibia strength at the distal and shaft sites, and shaft strength was also predicted by MVPA (β = 0.20) and impact counts (β = 0.21). Our models estimated a 3%-6%, 4%, or 4%-11% gain in tibia strength after increasing daily MVPA by 10-20 min, VPA by 5 min, or impacts by 30-100 counts, respectively. In conclusion, daily minutes of MVPA or VPA and impact counts are independent predictors of tibia but not radius strength. Objective recording of activities associated with forearm bone strength and trials testing the efficacy of increasing daily MVPA, VPA, and related impacts on bone strength development in children and youth are warranted.

Strain-specific differences in the development of bone loss and incidence of osteonecrosis following glucocorticoid treatment in two different mouse strains

ObjectiveGlucocorticoids (GCs) are commonly prescribed as treatment for chronic inflammatory diseases. Prolonged use of GCs is a common cause of atraumatic osteonecrosis (ON) and secondary osteoporosis. Currently, there is no effective treatment for this disease; therefore, a reliable animal model would be useful to study both the pathology and novel treatment strategies for patients with the disease. The aim of this study was to establish a validated, reproducible model of GC-induced ON and bone loss in two different mouse strains (BALB/c and C57BL/6). MethodsSeven-week-old male BALB/c (n = 32) and male C57BL/6 mice (n = 32) were randomised into placebo or GC groups and treated with daily 4 mg/L oral dexamethasone in drinking water for 90 days. Study outcome measures included histologic assessment of ON of the distal femur, bone mass and mechanical strength of tibia and lumbar vertebral body, osteoclast number, biochemical measure of bone formation and bone marrow fat quantitation. ResultsGC-induced ON lesions were observed in the distal femur in 47% of the male BALB/c mice and 25% of the male C57BL/6 mice. GC treatment decreased the trabecular bone volume and serum pro-collagen type 1N-protease (P1NP) in BALB/c mice compared with the placebo (p < 0.05) and reduced tibial bone strength in both BALB/c and C57BL/6 mice. GC-treated BALB/c mice had significantly greater marrow fat levels compared to the placebo group. ConclusionGC-induced ON was more prevalent in the male BALB/c mice compared to the male C57BL/6 mice. GC treatment significantly reduced bone mass, bone formation measured by P1NP, bone strength and increased marrow fat levels in male BALB/c mice. Therefore, the use of male BALB/c mice strain is recommended for both diagnostic and therapeutic studies for the prevention and treatment of ON and bone loss following prolonged treatment with GCs. The Translational Potential of this ArticleGCs are commonly used to treat patients with various chronic inflammatory diseases, and this is associated with both the development of ON and bone loss. Our study confirmed that the BALB/c mouse strain treated for 90 days with GC may be useful for developing novel treatments for ON.

Effect of supplementation of phytase to diets low in inorganic phosphorus on growth performance and mineralization of broilers

There has been discussion regarding microbial phytase replacing inorganic phosphorus (P) supplementation in broiler diets. Therefore, an experiment was conducted to examine the effect of phytase supplementation on diets low in inorganic P. Ross 308 broilers (n = 288) were fed one of 6 experimental diets in 4 phases. The control diet had 16.20, 10.90, 9.40, and 6.10g/kg inorganic P in the Starter, Grower 1, Grower 2 and Finisher phase respectively. The remaining diets had 10.50g/kg inorganic P in the Starter phase. Two of the diets had graded reductions in inorganic P of 5.10, 3.60, and 0.60g/kg or 2.00, 0.50, and 0.60g/kg for the Grower 1, Grower 2 and Finisher phase respectively, plus 500 FTU phytase. Three of the diets had inorganic P levels of 0.40, 0.50, and 0.60g/kg for the Grower 1, Grower 2 and Finisher diets respectively and either 500, 750, or 1,000 FTU phytase. Broiler performance was analyzed at d 10, 20, 26, and 35. On d 35, ileal calcium (Ca) and P digestibility and tibia bone strength, mineralization, and mineral content were analyzed. There were no significant differences between the control diet and diet containing 1,000 FTU phytase and low inorganic P in the grower or finisher diets based on bird performance, tibia strength, and Ca and P digestibility. Birds fed the control diet had significantly higher BWG (P = 0.001), bone strength (P < 0.001) and ash content (P < 0.001) compared to birds fed the diets with 500 FTU or 750 FTU phytase and low inorganic P in the grower and finisher stages. This may be due to incomplete dephosphorylation of the inositol ring of phytate with these doses of phytase, but with 1,000 FTU phytase there was almost complete phosphate hydrolysis of each phytate. This study showed that relying on phytase alone to ensure full supply of P in broiler diets is viable in finisher diets but is not recommended in grower diets unless phytase is supplied at doses of 1,000 FTU or greater.

Combined supplementation of organic acid blend and hydrolyzed yeast mixture increases growth performance and tibia bone strength in broilers

This study investigates the effects of hydrolyzed yeast mixture (HYM) and an organic acid blend (OAB) supplementation individually and in combination on growth performance and tibia bone characteristics of broilers. A total number of 128 one day- old chicks were divided into four different groups with each group having 4 replicates in a trial of 35 days. The first group was kept as control whereas, the second and third groups were given HYM and OAB respectively. The fourth group (HYM+OAB) was given combination of HYM and OAB. At the end of trial, two birds from each replicate were slaughtered for analysis. Results revealed that feed conversion ratio and live body weight were significantly higher in HYM+OAB compared to other groups. Tibial bone analysis revealed that robusticity and tibiotarsal indices were significantly better for HYM+OAB. It is concluded that compared to individual, combined supplementation of HYM and OAB is more beneficial in broilers.

Physical activity, but not sedentary time, influences bone strength in late adolescence.

To examine the influence of physical activity (PA) and sedentary time on bone strength, structure, and density in older adolescents. We used peripheral quantitative computed tomography to estimate bone strength at the distal tibia (8% site; bone strength index, BSI) and tibial midshaft (50% site; polar strength strain index, SSIp) in adolescent boys (n = 86; 15.3 ± 0.4years) and girls (n = 106; 15.3 ± 0.4years). Using accelerometers (GT1M, Actigraph), we measured moderate-to-vigorous PA (MVPAAccel), vigorous PA (VPAAccel), and sedentary time in addition to self-reported MVPA (MVPAPAQ-A) and impact PA (ImpactPAPAQ-A). We examined relations between PA and sedentary time and bone outcomes, adjusting for ethnicity, maturity, tibial length, and total body lean mass. At the distal tibia, MVPAAccel and VPAAccel positively predicted BSI (explained 6-7% of the variance, p < 0.05). After adjusting for lean mass, only VPAAccel explained residual variance in BSI. At the tibial midshaft, MVPAAccel, but not VPAAccel, positively predicted SSIp (explained 3% of the variance, p = 0.01). Lean mass attenuated this association. MVPAPAQ-A and ImpactPAPAQ-A also positively predicted BSI and SSIp (explained 2-4% of the variance, p < 0.05), but only ImpactPAPAQ-A explained residual variance in BSI after accounting for lean mass. Sedentary time did not independently predict bone strength at either site. Greater tibial bone strength in active adolescents is mediated, in part, by lean mass. Despite spending most of their day in sedentary pursuits, adolescents' bone strength was not negatively influenced by sedentary time.

The strength of weight-bearing bones is similar in amenorrheic and eumenorrheic elite long-distance runners.

Regular intense endurance exercise can lead to amenorrhea with possible adverse consequences for bone health. We compared whole body and regional bone strength and skeletal muscle characteristics between amenorrheic (AA: n=14) and eumenorrheic (EA: n=15) elite adult female long-distance runners and nonathletic controls (C: n=15). Participants completed 3-day food diaries, dual-energy X-ray absorptiometry (DXA), magnetic resonance imaging (MRI), peripheral quantitative computed tomography (pQCT), and isometric maximal voluntary knee extension contraction (MVC). Both athlete groups had a higher caloric intake than controls, with no significant difference between athlete groups. DXA revealed lower bone mineral density (BMD) at the trunk, rib, pelvis, and lumbar spine in the AA than EA and C. pQCT showed greater bone size in the radius and tibia in EA and AA than C. The radius and tibia of AA had a larger endocortical circumference than C. Tibia bone mass and moments of inertia (Ix and Iy) were greater in AA and EA than C, whereas in the radius, only the proximal Iy was larger in EA than C. Knee extensor MVC did not differ significantly between groups. Amenorrheic adult female elite long-distance runners had lower BMD in the trunk, lumbar spine, ribs, and pelvis than eumenorrheic athletes and controls. The radius and tibia bone size and strength indicators were similar in amenorrheic and eumenorrheic athletes, suggesting that long bones of the limbs differ in their response to amenorrhea from bones in the trunk.

Efficacy of a multi-component exercise programme and nutritional supplementation on musculoskeletal health in men treated with androgen deprivation therapy for prostate cancer (IMPACT): study protocol of a randomised controlled trial

BackgroundProstate cancer is the most commonly diagnosed cancer in men in developed countries. Androgen deprivation therapy (ADT) is a systemic treatment shown to increase survival in selected patients with prostate cancer. The use of ADT continues to increase for all stages and grades of prostate cancer despite known treatment-induced adverse effects. The primary aim of this study is to examine the efficacy of a targeted, multi-component resistance and impact-loading exercise programme together with a daily protein-, calcium- and vitamin D-enriched supplement on bone health in men treated with ADT for prostate cancer. Secondary aims are to determine the effects of this intervention on measures of total body and regional body composition, cardiometabolic risk, inflammatory markers, health-related quality of life and cognitive function.MethodsThis study is a two-arm randomised controlled trial. Men currently treated with ADT for prostate cancer will be randomised to either a 52-week, community-based, exercise training and nutritional supplementation intervention (n = 51) or usual care control (n = 51). Participants will be assessed at baseline, 26 weeks and 52 weeks for all measures. The primary outcome measures are proximal femur and lumbar spine areal bone mineral density (BMD). Secondary outcomes comprise: changes in tibial and radial bone structure and strength, total body and regional body composition, muscle strength and function, as well as cardiometabolic health, catabolic/inflammatory and anabolic/anti-inflammatory cytokines, health-related quality of life and cognitive function.DiscussionThis study investigates whether a multi-component intervention incorporating a targeted bone and muscle-loading programme in combination with a protein-, calcium- and vitamin D-enriched supplement can ameliorate multiple adverse effects of ADT when compared to usual care. The results will contribute to the development of exercise training and nutrition guidelines for optimising overall health in men treated with ADT for prostate cancer.Trial registrationAustralia New Zealand Clinical Trial Registry (ANZCTR), ID: ACTRN12614000317695. Registered on 25 march 2014.

Effects of a Randomized Weight Loss Intervention Trial in Obese Adolescents on Tibia and Radius Bone Geometry and Volumetric Density.

Obese adolescents have increased fracture risk, but effects of alterations in adiposity on bone accrual and strength in obese adolescents are not understood. We evaluated 12-month changes in trabecular and cortical volumetric bone mineral density (vBMD) and cortical geometry in obese adolescents undergoing a randomized weight management program, and investigated the effect of body composition changes on bone outcomes. Peripheral quantitative computed tomography (pQCT) of the radius and tibia, and whole-body dual-energy X-ray absorptiometry (DXA) scans were obtained at baseline, 6 months, and 12 months in 91 obese adolescents randomized to standard care versus behavioral intervention for weight loss. Longitudinal models assessed effects of body composition changes on bone outcomes, adjusted for age, bone length, and African-American ancestry, and stratified by sex. Secondary analyses included adjustment for physical activity, maturation, vitamin D, and inflammatory biomarkers. Baseline body mass index (BMI) was similar between intervention groups. Twelve-month change in BMI in the standard care group was 1.0 kg/m2 versus -0.4 kg/m2 in the behavioral intervention group (p < 0.01). Intervention groups were similar in bone outcomes, so they were combined for subsequent analyses. For the tibia, BMI change was not associated with change in vBMD or structure. Greater baseline lean body mass index (LBMI) associated with higher cortical vBMD in males, trabecular vBMD in females, and polar section modulus (pZ) and periosteal circumference (Peri-C) in both sexes. In females, change in LBMI positively associated with gains in pZ and Peri-C. Baseline visceral adipose tissue (VFAT) was inversely associated with pZ in males and cortical vBMD in females. Change in VFAT did not affect bone outcomes. For the radius, BMI and LBMI changes positively associated with pZ in males. Thus, in obese adolescents, weight loss intervention with modest changes in BMI was not detrimental to radius or tibia bone strength, and changes in lean, but not adiposity, measures were beneficial to bone development. © 2017 American Society for Bone and Mineral Research.

Sequential treatment with zoledronic acid followed by teriparatide or vice versa increases bone mineral density and bone strength in ovariectomized rats

Bisphosphonates (BPs) and teriparatide (TPTD) are both effective treatments for osteoporosis, but BP treatment prior to daily TPTD treatment has been shown to impair the effect of TPTD in some clinical studies. In contrast, the loss of bone mineral density (BMD) that occurs after withdrawal of TPTD can be prevented by BP treatment. Although various studies have investigated the combination and/or sequential use of BP and TPTD, there have been no clinical studies investigating sequential treatment with zoledronic acid (ZOL) and TPTD (or vice versa). In this study, we evaluated the effects of sequential treatment with TPTD followed by ZOL, and ZOL followed by TPTD, using ovariectomized (OVX) rats.Two months after OVX, osteopenic rats were treated with ZOL, TPTD, or vehicle for a period of 4months (first treatment period), and then the treatments were switched and administered for another 4months (second treatment period).The group treated with ZOL followed by TPTD showed an immediate increase in BMD of the proximal tibia and greater BMD and bone strength of the lumbar vertebral body, femoral diaphysis, and proximal femur than the group treated with ZOL followed by vehicle. Serum osteocalcin, a marker of bone formation, increased rapidly after switching to TPTD from ZOL.The group treated with TPTD followed by ZOL did not lose BMD in the proximal tibia after TPTD was stopped, while the group treated with TPTD followed by vehicle did lose BMD. The BMD and bone strength of the lumbar vertebral body, femoral diaphysis, and proximal femur were greater in the group treated with TPTD followed by ZOL than in the group treated with TPTD followed by vehicle. The increase in serum osteocalcin and urinary CTX after withdrawal of TPTD was prevented by the switch from TPTD to ZOL.In conclusion, our results demonstrate that switching from ZOL to TPTD resulted in a non-attenuated anabolic response in the lumbar spine and femur of OVX rats. In addition, switching from TPTD to ZOL caused BMD to be maintained or further increased. If these results can be reproduced in a clinical setting, the sequential use of ZOL followed by TPTD or vice versa in the treatment of osteoporosis patients would contribute to increases in BMD that, hopefully, would translate into a corresponding decrease in the incidence of vertebral and non-vertebral fractures.

Strength adaptations of the tibia bone for prescribed sets of isometric forces and joint angles

The isometric exercise induced tibial bone strength adaptations due to various prescribed net resultant forces generated by a leg arranged with specified hip, knee, and ankle joint angles were examined using a computationally based bone shape adaptation model. With the leg straight, or the knee flexed at 90°, and the hip either neutral or flexed by 45°, a force was repeatedly generated at the toe either anteriorly, posteriorly, superiorly, or inferiorly, in paired sequences of these directions, or in a clockwise pattern of all four directions. Model-predicted individual muscle forces, amounts of cortical bone surface accretion or resorption, and the resulting changes in bone stress distributions were compared. Similarities between adaptations to specific combinations of joint angles and net resultant force directions were found to follow similarities in the bone stress distributions rather than in muscle activity. The ratio of standard deviation to the surface-averaged measure of local stress was a good predictor of potential improvement in overall stress state uniformity. With flexed knee and neutral hip, greater adaptive improvements in tibial surface stress uniformity were found than with both joints flexed. Flexed configurations caused greater changes and overall strength improvements than exercises performed with a straight leg. Regions of local tibial cortical thickening were identified for specific joint angles and single-load resultant force directions. Sequential series of loads were also identified to enhance these effects and mitigate concurrent thinning in other regions. The presented information can aid in the design and analysis of targeted muscle and bone strengthening exercises.

Effects of a 20-week high-intensity strength and sprint training program on tibial bone structure and strength in middle-aged and older male sprint athletes: a randomized controlled trial.

High-load, high-speed and impact-type exercise may be an efficient way of improving bone strength even in old age. We evaluated the effects of combined strength and sprint training on indices of bone health in competitive masters athletes, who serve as a group of older people who are likely to be able to participate in vigorous exercise of this kind. Seventy-two men (age 40-85) were randomized into an experimental (EX, n=40) and a control (CTRL, n=32) group. EX participated in a 20-week program combining heavy and explosive strength exercises with sprint training. CTRL maintained their usual, run-based sprint training schedules. Bone structural, strength and densitometric parameters were assessed by peripheral QCT at the distal tibia and tibial midshaft. The intervention had no effects on distal tibia bone traits. At the mid-tibia, the mean difference in the change in cortical thickness (ThCO) in EX compared to CTRL was 2.0% (p=0.007). The changes in structure and strength were more pronounced in the most compliant athletes (training adherence >75%). Compared to CTRL, total and cortical cross-sectional area, ThCO, and the area and density-weighted moments of inertia for the direction of the smallest flexural rigidity (I minA , I minD ) increased in EX by 1.6-3.2% (p=0.023-0.006). Polar mass distribution analysis revealed increased BMC at the anteromedial site, whereas vBMD decreased (p=0.035-0.043). Intensive strength and sprint training improves mid-tibia structure and strength in middle-aged and older male sprint athletes, suggesting that in the presence of high-intensity loading exercise, the adaptability of the bone structure is maintained during aging.

Effects of Recombinant Human Lactoferrin on Osteoblast Growth and Bone Status in Piglets

ABSTRACTLactoferrin (LF), an ~80 kDa iron-binding glycoprotein, modulates many biological effects, including antimicrobial and immunomodulatory activities. Recently, it was shown that LF also regulates bone cell activity, suggesting its therapeutic effect on postmenopausal bone loss. However, a minimal amount is known regarding the effects of recombinant human LF (rhLF) supplementation on bone status in young healthy infants. We found osteoblast cell differentiation was significantly promoted in vitro. Furthermore, treatment of human osteoblast cells with rhLF rapidly induced phosphorylation of p44/p42 mitogen-activated protein kinase (p44/p42 MAPK, ERK1/2). In order to investigate the effects of rhLF on bone status in vivo, we used a piglet model, which is a useful model for human infants. Piglets were supplemented with rhLF milk for 30 days. Bone formation markers, Serum calcium concentration, bone mineral density (BMD), bone mineral content (BMC), tibia bone strength, and the overall metabolite profile analysis showed that rhLF was advantageous to the bone growth in piglets. These findings suggest that rhLF supplementation benefits neonate bone health by modulating bone formation.

Muscle Function Tests as Field Measures of Tibial Bone Strength

Muscle Function Tests as Field Measures of Tibial Bone Strength

Calcium intake below the recommended dietary allowance is associated with lower tibia bone mineral content and strength in young adults entering initial military training

BackgroundCalcium (Ca), a critical micronutrient for bone health, has been deemed a nutrient of public health concern due to consumption at levels below the recommended dietary allowance (RDA). Stress fracture risk is elevated during initial military training (IMT) and supplemental Ca during IMT reduces stress fracture incidence.ObjectiveTo assess dietary Ca in young adults entering IMT and to determine whether habitual Ca intake is associated with indices of bone health at the tibia, a commonly fractured site.MethodsA retrospective analysis was performed using baseline data from 3 randomized control trials that assessed the efficacy of Ca and vitamin D supplementation for optimizing bone health during IMT in Army, Air Force, and Marine recruits. Ca intake was estimated from a semi‐quantitative food frequency questionnaire and adequacy was based on the age‐specific RDAs. Bone health was evaluated by peripheral quantitative computed tomography (pQCT) of the tibia at the metaphysis and diaphysis. The associations between pQCT parameters and Ca intake adequacy were assessed by multivariate regression (SPSS, v21) controlling for age, sex, race, self‐reported physical activity, BMI, smoking, education level, and use of Depo Provera.ResultsOf the 399 study participants (n=223 females, n=180 males), 251 (62%) did not meet the RDA for Ca. Adequate Ca intake was positively associated with total bone mineral content (BMC; B=.091, p=.005) and strength (B=.084, p=.020) at the metaphysis. When participants were stratified by sex, 70% of females and 52% of the males did not meet the RDA. In the female cohort, adequate Ca intake was positively associated with BMC (B=.169, p=.011) and strength (B=.142, p=.033) at the metaphysis and cortical BMC (B=.134, p=.042) at the diaphysis. There were no associations in the male cohort.ConclusionAdequate Ca intake in young adults is positively associated with measures of tibia BMC and strength. As recruits with Ca intake below the RDA at the start of training may experience diminished bone health potentially leading to greater injury susceptibility, adequate Ca intake should be emphasized prior to initiating military training.Disclaimer: The views expressed in this abstract are those of the authors and do not reflect the official policy of the Department of Army, Department of Defense, or the U.S. Government.Support or Funding InformationResearch supported by USAMRMC, DHP, and in part by an appointment to the Postgraduate Research Participation Program administered by the Oak Ridge Institute for Science and Education.

Catastrophic Varus Collapse of the Tibia in Obese Total Knee Arthroplasty

BackgroundMechanical complications have been underemphasized in reports on total knee arthroplasty (TKA) in obese patients. Noticing an increased prevalence of varus collapse of the tibia in obese total knee patients, we sought to determine if variability in proximal tibial cancellous bone strength played a role in failure. We attempted to define a cancellous threshold above which alternative methods of fixation should be used. MethodsOne thousand one hundred six revision TKAs from 2004-2014 identified 35 patients with varus collapse of the tibia, defined as a change in component position of >10°. Variables analyzed included weight, alignment, component size, and proximal tibial bone stress. Postoperative alignment was compared with prerevision alignment. To calculate tibial stress the following formula was used: mass (kg) × acceleration of gravity (9.8 m/s2)/tibial surface area (mm2) = pascals or N/M2. ResultsTwenty-nine of 35 patients weighed >200 lbs, whereas 17 of 35 patients weighed >250 lbs (range 130-354 lbs). Average body mass index was 40.5 kg/m2 (range 24-61 kg/m2). Twenty-seven of 35 failed tibial components were in the lower half of the manufacturer's tibial size offering. Postsurgical alignment averaged 4.9° valgus (range 2° varus-7° valgus) and collapsed an average of 14.9° (range 10°-22°) before revision. Proximal tibial bone stress averaged 334,324 Pascals (range 188,524-601,416). Twenty-five of 35 patients had proximal tibial bone stress >300,000 Pascals. ConclusionDespite good initial primary TKA alignment, we report catastrophic varus collapse of tibial components in obese patients with small tibial components. When a cancellous threshold of 300,000 Pascals is exceeded, strong consideration should be given to either optimizing the patient's weight or using a longer tibial stem to dissipate forces on proximal tibia.

Using three-point bending to evaluate tibia bone strength in ovariectomized young mice.

It is well known that estrogen deficiency induces a deterioration of bone strength in aged females. The aim of this study is to determine the effect of estrogen depletion on tibia bone strength in sexually mature mice that are still undergoing skeletal maturation. At 8weeks of age, C57BL/6 female mice underwent an ovariectomy (OVX) or sham (SHAM) surgery. Mice were killed at 2, 4, or 8weeks post-surgery. Tibia length and cross-sectional area continued to increase in both treatment groups until 4weeks post-surgery. Compared to SHAM mice, OVX mice demonstrated a significant reduction in uterine weight and plasma estrogen levels. Three-point bending was used to quantify the mechanical properties (breaking point, stress, stiffness, and elasticity) of the tibia. The tibias from the SHAM mice had a higher breaking point than all the age-matched OVX mice. At 8weeks post-surgery, the tibias from the SHAM mice demonstrated higher elasticity, stress, and stiffness than the younger SHAM mice and the age-matched OVX mice. Compared to the SHAM mice, our study suggests that (1) there is a reduction in the mechanical strength of tibias from young OVX mice, and (2) the greatest decline in tibia strength of the OVX mice was once they reached skeletal maturity.

Dietary non-phytate phosphorus requirement of broilers fed a conventional corn-soybean meal diet from 1 to 21 d of age

An experiment was conducted to investigate the effect of dietary non-phytate phosphorus (NPP) level on growth performance, bone characteristics and phosphorus metabolism-related gene expressions, so as to evaluate the dietary NPP requirement of broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age. A total of 540 day-old Arbor Acres male chicks were randomly allocated to one of nine treatments with six replicate cages of 10 birds per cage in a completely randomized design, and fed a basal corn-soybean meal diet (containing 0.08% of NPP) supplemented with 0.10, 0.15, 0.25, 0.30, 0.35, 0.40, 0.45, or 0.50% of inorganic phosphorus in the form of CaHPO4·2H2 O, respectively. Each diet contained the constant calcium content of about 1.0%. The results showed that daily weight gain, serum inorganic P, tibia bone strength, tibia ash percentage, tibia bone mineral content (BMC) and density (BMD), middle toe ash percentage, middle toe BMC and BMD were affected (P < 0.0001) by dietary NPP level, and increased linearly (P < 0.0001) and quadraticly (P < 0.004) as dietary NPP levels increased. The gene expression of type IIb sodium-phosphate cotransporter (NaPi-IIb) in the duodenum was affected (P < 0.03) and decreased linearly (P < 0.002) as dietary NPP levels increased. Dietary NPP requirements estimated based on fitted broken-line models (P < 0.0001) of the sensitive indices including daily weight gain, tibia bone strength, tibia ash percentage, tibia BMC and BMD as well as middle toe ash percentage were 0.34∼0.39%. The results from this study indicate that tibia BMC and BMD might be new, sensitive, and noninvasive criteria to evaluate the dietary NPP requirements of broilers, and the dietary NPP requirement is 0.39% for broiler chicks fed a conventional corn-soybean meal diet from 1 to 21 d of age.

Meagre effects of disuse on the human fibula are not explained by bone size or geometry.

The fibula supports only a small and highly variable proportion of shank compressive load (-8 to +19%), and little is known about other kinds of stresses. Hence, whilst effects of habitual loading on tibia are well-known, fibula response to disuse is difficult to predict. Therefore, we assessed fibular bone strength using peripheral quantitative computed tomography (pQCT) at 5% increments from 5 to 90% distal-proximal tibia length in nine participants with long-term spinal cord injury (SCI; age 39.2±6.2years, time since injury 17.8±7.4years), representing a cross-sectional model of long-term disuse and in nine able-bodied counterparts of similar age (39.6±7.8years), height and mass. There was no group difference in diaphyseal fibula total bone mineral content (BMC) (P=0.22, 95% CIs -7.4 % to -13.4 % and +10.9 % to +19.2 %). Site by group interactions (P<0.001) revealed 27 and 22% lower BMC in SCI at 5 and 90% (epiphyseal) sites only. Cortical bone geometry differed at mid and distal diaphysis, with lower endocortical circumference and greater cortical thickness in SCI than able-bodied participants in this region only (interactions both P<0.01). Tibia bone strength was also assessed; bone by group interactions showed smaller group differences in fibula than tibia for all bone parameters, with opposing effects on distal diaphysis geometry in the two bones (all Ps<0.001). These results suggest that the structure of the fibula diaphysis is not heavily influenced by compressive loading, and only mid and distal diaphysis are influenced by bending and/or torsional loads. The fibula is less influenced by disuse than the tibia, which cannot satisfactorily be explained by differences in bone geometry or relative changes in habitual loading in disuse. Biomechanical study of the shank loading environment may give new information pertaining to factors influencing bone mechanoadaptation.

Are milk and alternatives and fruit and vegetable intakes during adolescence associated with cortical and trabecular bone structure, density, and strength in adulthood?

The purpose of this study was to investigate whether adolescents with high intake of milk and alternatives (M&A) or fruit and vegetables (F&V) had better adult bone structure and strength compared to those with low intake levels. We analyzed data from 47 males and 69 females enrolled in the Pediatric Bone Mineral Accrual Study (PBMAS 1991-2011), who had one peripheral quantitative computed tomography scan at age 29 ± 2years. We measured radius and tibia shaft total area (ToA), cortical area (CoA), cortical content (CoC), cortical density, bone strength (SSIp), and muscle area, as well as distal radius and tibia ToA, total density, trabecular area, trabecular content, trabecular density, and bone strength (BSIc). Sequential 24-h recalls were used to assess M&A and F&V intake; participants were grouped for their mean intake during adolescence (low = bottom quartile, moderate = middle quartiles, high = top quartile) and were compared using multivariate analysis of covariance while adjusting for adult height, muscle area, physical activity, energy and calcium intake and adolescent energy intake, and physical activity. Females with high M&A intake compared to low M&A intake group (mean 3.8 vs. 1.3 servings/day, respectively) had greater adult ToA (14%, p < 0.05), CoA (15%, p < 0.01), and CoC (16%, p < 0.01) at radius shaft. Females with moderate F&V intake compared to low F&V intake group (mean 3.7 vs. 2.1 servings/day, respectively) had greater adult ToA (8.5%, p < 0.05) at distal tibia. Higher intake of M&A or F&V during adolescence had a long-term beneficial effect on bone structure in females, an association not observed in males.

Effects of Golden Apple Snail (Pomacea Canaliculata, Lamarck) Shell Particle Size on Growth Performance, Carcass Quality, Bone Strength and Small Intestinal Histology in Thai Native Chickens (Pradu Hang Dum Chiangmai 1)

&lt;p class="1Body"&gt;To study whether the particle size of golden apple snail (&lt;em&gt;Pomacea Canaliculata&lt;/em&gt;, Lamarck) shell induces negative effects on the growth performance, carcass quality, bone strength and small intestinal histology in Thai native chickens (Pradu Hang Dum Chiangmai 1), 192 chickens, both male and female, were divided into 4 groups with 4 replicates of 12 chickens each at 5 weeks of age. The control group received limestone as a source of calcium. The experimental groups received diets containing golden apple snail shell particles, with sizes ranging from 0:50 to 1:00, from 1.00 to 1.70, and from 1.70 to 2.80 mm as a calcium source. Feed intake and weight were measured weekly, and carcass quality, tibial bone strength and small intestinal histology were observed at 16 weeks of age. The data of growth performance, carcass quality, tibial bone strength and small intestinal histology did not present negative results after feeding any of the golden apple snail shell sizes. On the contrary, a slightly higher weight gain was observed in the group consuming the 1.00 to 1.70 mm snail shell particles during the period from the 13th to the 16th week. Improved carcass quality and pectoralis major and tibial bone strength, as well as significantly increased duodenal villus surface and jejunal crypt cell numbers (p &amp;lt; 0.05) were observed in the group fed the 1.00 to 1.70 mm snail shell particles. These results suggest that golden apple snail shell particles between 1.00 and 1.70 mm can improve growth performance due to hypertrophied intestinal function.&lt;/p&gt;