Age-related changes in bone mineral density, cross-sectional area and the strength of long bones in the hind limbs and first lumbar vertebra in female Wistar rats

Age-related changes in bone mineral density (BMD) and cross-sectional area and bone strength index (SSI) of the femur, tibia, humerus, and first lumbar vertebra in female Wistar (WM/MsNrs) rats were examined by a quantitative computed tomography (pQCT) method. One hundred and sixteen virgin female Wistar (WM/MsNrs) rats aged 2-33 months were used. The data indicate that the total BMD values of metaphyses and diaphyses of long bones increased until 12 months, then decreased to a varying degree depending on the bone after 15-24 months, but the values of cortical and trabecular BMD with age were not always similar to the total BMD value. Nevertheless, the values for cross-sectional area and SSI in the long bones increased regardless of the total BMD decrease with age, indicating that this increase might have been due to a characteristic of the modeling pattern in rats. The total and cortical BMD values in the first lumbar vertebra decreased after 18 months, and SSI did after 15 months. The data obtained in this study were compared with those obtained from males in a previous study. In conclusion, it was indicated that in this strain the rats over 12 months with the highest total BMD values in the femur and tibia, and before the onset of various tumors, are useful as a model animal for osteoporosis experiments and observation of senile bone change.     

Age-related changes of bone mineral density and microarchitecture in miniature pigs

Bone mineral density (BMD), distribution of its density and bone histomorphometric parameters were evaluated in lumbar vertebra of normally growing miniature pigs. The fourth lumbar vertebra (L4) of the G?ttingen miniature pig were used in this cross-sectional study in vitro. The BMD of the miniature pig was similar to that of humans in tendency of gender differences and some growth patterns during puberty. In these regards this animal appears useful as a model for human bone study. However, the trabecular and cortical BMDs of lumbar spine were extremely high value (399.43 +/- 26.36 mg/cm(3) in female trabeculae; 973.06 +/- 69.55 mg/cm(3) in female cortical bone; 419.04 +/- 34.84 mg/cm(3) in male trabeculae; 1038.81 +/- 125.72 mg/cm(3) in male cortical bone in pigs 30 months or more). Furthermore, histomorphometric analysis yielded values that were remarkably different from those found in humans. From these results, it was revealed that miniature pig had a higher bone mass and denser trabecular network than human, indicating that its bone is probably stronger. Therefore, care should be taken in choosing the miniature pig as a bone study model.     

硒对STZ诱发糖尿病大鼠骨密度影响的研究初报

比较了在低硒饲料的基础上补充不同形态硒对糖尿病大鼠骨密度的影响。健康SD大鼠 1 2 8只 ,体重 50～ 60 g,随机分为 4组 ,每组 32只 ,雌雄各半 ,其中Ⅰ组为低硒对照组 (饲料含硒量 0 0 37mg/kg) ;Ⅱ组为补充亚硒酸钠组 (饲料含硒量 0 3mg/kg) ;Ⅲ组为补充富硒麦芽组(饲料含硒量 0 3mg/kg) ;Ⅳ组为补充富硒酵母组 (饲料含硒量 0 3mg/kg)。Ⅱ、Ⅲ、Ⅳ组的饲料均是在Ⅰ组低硒饲料的基础上分别添加适量的亚硒酸钠、富硒麦芽、富硒酵母后配制而成。喂饲 5周后 ,Ⅰ、Ⅱ、Ⅲ、Ⅳ组用链脲佐菌素 (streptozotocin ,STZ)按 60mg/kg腹腔注射诱发糖尿病 ,继续饲喂 6周。用单光子吸收法测定各组大鼠的肱骨、股骨、胫骨、桡骨的骨密度。结果表明 :①STZ致糖尿病大鼠的骨密度随时间的延长有逐渐下降的趋势。Ⅱ、Ⅲ、Ⅳ补硒组大鼠可以在一定时间内延缓STZ致糖尿病大鼠的骨密度下降。在此期间骨密度的下降以肱骨出现最早 ,股骨次之 ,桡骨、胫骨再次之。②饲料补硒组糖尿病大鼠的肱骨、股骨中硒的含量较饲料低硒组糖尿病大鼠的肱骨、股骨中硒的含量显著提高。③补充硒的形态 ,即有机硒 (富硒麦芽、富硒酵母 )或无机硒 (亚硒酸钠 )对糖尿病大鼠肱骨、股骨、胫骨、桡骨的骨密度影响差异不显著。     

Effect of prepubertal ovariohysterectomy on bone mineral density and bone mineral content in puppies

In this study, dual energy X-ray absorptiometry (DXA) was performed on the calcaneus (CAL) and accessory carpal bone (ACB) of early-age neutered (n = 11) and sham-operated puppies (n = 10) to investigate changes in bone mineral density (BMD) and bone mineral content (BMC) over time. Prepubertal ovariohysterectomy and sham surgery were performed at 10 weeks, while BMD and BMC were measured at 12, 16, 20 and 24 weeks of age. BMD and BMC of CAL and ACB of ovariohysterectomised puppies were found to be higher. The differences between the groups were statistically unimportant; however, the fourth measurement of the ACB showed a significant (P < 0.05) difference. Sexually intact puppies weighed less than gonadectomised puppies in all measurements. Because of the positive correlations between body weight and bone mineral density, BMD and BMC of early-age neutered puppies were found to be higher. These results suggest that BMD and BMC are not affected by prepubertal ovariohysterectomy until six months of age in mixed-breed puppies.     

Influence of intensity and changes of physical activity on bone mineral density of immature equine subchondral bone

Reasons for performing study: Subchondral bone provides structural support to overlying articular cartilage and plays an important biomechanical role in osteochondral diseases. Mechanical features of bone correlate strongly with bone mineral density, which is directed by the loading conditions to which the tissue is subjected. Objective: To investigate the influence of physical activity levels on subchondral bone mineral density (sBMD) in foals during early development. Methods: Three groups of foals were subjected to different physical activity levels from birth until age 5 months. A proportion of these foals were subjected to euthanasia at 5 months while remaining foals were subjected to similar physical activity levels for 6 months until euthanasia at 11 months. Osteochondral specimens were collected for measurement of sBMD with peripheral quantitative computed tomography at 2 differently loaded anatomical sites of the proximal phalangeal bone at 1, 2, 3, 4 and 5 mm depth from the osteochondral junction. Results: Growth significantly increased sBMD but by a different amount depending on anatomical location and physical activity level. Significantly higher sBMD was found at the habitually loaded central area in comparison to the intermittently peak loaded marginal site. Exercise increased sBMD throughout the whole depth of analysed tissue, but changes were generally more obvious at a depth of 2 mm. Interestingly, foals subjected to additional sprint training preserved the exercise‐induced sBMD increase at the habitually loaded central area during the 6 months of the second phase of the study. Conclusions: Habitual low‐intensity loading elicits a greater response in sBMD in quantitative terms than high‐intensity low‐frequency loading at the sites investigated in this study. Future sBMD may be influenced by means of well‐tailored exercise regimens at young age. Potential relevance: Specific physical activity levels during early development may potentially reduce the prevalence of osteochondral injury later in life.     

Effects of ovariectomy on bone metabolism and bone mineral density in spontaneously diabetic Torii-Lepr(fa) rats

The Spontaneously Diabetic Torii-Lepr(fa) (SDT- fa/fa) rat is a new model of obese type 2 diabetes. The female SDT-fa/fa rat shows obesity, hyperglycemia and hyperlipidemia from a young age. However, it is not known whether diabetes and estrogen deficiency can lead to bone abnormalities in the female SDT-fa/fa rat. The objective of the present study was to investigate the effects of ovariectomy (OVX) on bone metabolism and bone mineral density (BMD) in the female SDT-fa/fa rat. Female Sprague-Dawley rats were used as control animals. The BMDs of the whole tibia and fifth lumbar (L5) vertebral body were analyzed at 30 weeks after OVX. Serum osteocalcin, a bone formation marker, and urine deoxypyridinoline (DPD), a bone resorption marker, were sequentially analyzed before and at 5, 15 and 30 weeks after OVX. Serum osteocalcin and urine DPD levels were lower in SDT-fa/fa rats than in control rats before OVX. Both serum osteocalcin and urine DPD levels were elevated in control rats 5-30 weeks after OVX, but only the urine DPD levels were elevated in SDT-fa/fa rats 5-30 weeks after OVX. SDT-fa/fa rats showed a decrease in the BMDs of the whole tibia and L5 vertebral body compared with control rats. OVX decreased the BMDs of the whole tibia and L5 vertebral body in control rats, but not in SDT-fa/fa rats. These data suggest that estrogen deficiency is not a risk factor for bone loss in type 2 diabetes mellitus.     

Long term studies on bone mineral changes during different lactations in Swedish dairy cattle

Changes in the bone mineral content (BMG) during the first 4 lactations were continuously studied between July 1977 and February 1982 in a total number of 103 dairy cows of different breeds and rearing intensities. The BMG was measured by dichromatic photon absorptiometry in 2 coccygeal vertebrae. Although great individual variations were found, the changes in BMG during the lactation followed a typical pattern with high values during the dry period and low values after calving and during mid-lactation. The influence of body weight on the BMC value is discussed. The changes in BMC were more accentuated during the first lactation, as compared to the subsequent lactations. This could indicate a metabolically more active skeleton in younger cows. In this study no difference in BMC pattern was observed between cows affected or not affected by parturient paresis.     

Signalment differences in bone mineral content and bone mineral density in canine appendicular bones. A cadaveric study.

The objective was to determine signalment-related differences in bone mineral content (BMC) and bone mineral density (BMD) in dogs. Unilateral appendicular bones were harvested from 62 canine cadavers. Mid-diaphyseal regions of interest (ROIs) were scanned using a Hologic DXA device Braincon, Vienna, Austria). BMC and BMD were calculated within this region. Middle-aged dogs (3-10 years) revealed the highest BMC and BMD levels. Mean BMC and BMD were higher in males compared to females. Furthermore, body-weight of the male dogs was significantly higher compared to the females (P < 0.0001). Body weight and bone length were significantly associated with BMC and BMD (P < or = 0.023) in all bones but the radius. These data suggest that BMC and BMD appear to be highest in male large-breed dogs with a body weight greater than 30 kg. These results may help determine risk factors in fracture development and healing.     

Differences in bone mineral content and density between male and female budgerigars (Melopsittacus undulatus) during the non-reproductive season

It is known that female birds increase medullary mineral stores in long bones shortly before egg laying. Here, we present results from two groups of budgerigars, in both of which females had significantly higher bone mineral contents and densities, as measured by peripheral quantitative computed tomography of the tibiotarsus, during a reproductively dormant period. The results could indicate that female birds can accumulate mineral stores outside of the breeding season.     

Total body and regional measurements of bone mineral content and bone mineral density in pigs by dual energy X-ray absorptiometry.

Dual energy X-ray absorptiometry (DXA) was used to make total body and regional measurements of bone mineral content, bone mineral density, and bone area during the growth of pigs from 3 to 138 kg. In all, 1,053 total body scans were performed on 587 live pigs. Regional measurements consisted of the front legs, trunk, and back legs. In addition, bone mineral density readings were recorded for the head, pelvis, spine, and ribs. From about 5 to 75 kg, a greater percentage of the total body bone mineral content (BMC) was located in the trunk region. However, the percentage of BMC in the front and back legs continued to increase linearly whereas the percentage of BMC in the trunk region peaked at about 25 kg and then decreased logarithmically. Allometric analysis revealed that up to about 30 kg the BMC increased more rapidly in the trunk region compared to the front or back leg regions (P > 0.05), but after 30 kg the increase in BMC was more rapid in the leg regions (P < 0.05). Overall, the rate of increase in BMC in the back legs was slightly more than in the front legs (P > 0.05). Positive allometric growth of BMC was observed when compared with the increase in bone area for the same region. By far, the highest measured level of bone mineral density (BMD) was in the head region (P < 0.05), followed in order by the front legs, spine, back legs, pelvis, and ribs. Over the entire range of growth from 3 to 138 kg, the highest relative growth coefficient for the increase in BMD occurred in the pelvic and back leg regions and the lowest was in the ribs (P < 0.05). For pigs < 30 kg, the highest growth coefficient for BMD relative to BW was in the spine (P > 0.05). The growth coefficients for BMD in the back legs and total body increased in pigs > 30 kg and those of the front legs and trunk regions decreased.     

Age-related changes for serum bone metabolism markers in thoroughbred and quarter horse foals

Serum bone specific alkaline phosphatase (BALP) and osteocalcin were measured in 9 Thoroughbred and 4 Quarter Horse (QH) foals. Eight were colts, and 5 were fillies. The first blood sample was collected from foals between 10 and 14 hours after birth on day 1. Blood then was collected on days 3, 6, 9, 12, 15, 18, 21, 28, 35, 42, 49, 56, 70, 84, 98, and 112 between 7:00 and 9:00 am. Serum bone metabolism marker raw data were analyzed with analysis of variance with repeated measures over time with gender and breed in the model. Average serum osteocalcin concentrations were higher for Thoroughbred than QH foals: 152.1 ± 4.6 ng/mL and 131.3 ± 6.3 ng/mL (mean ± standard error), respectively (P = .01). No overall differences were seen for gender (P = .10). However, on day 1, colts had higher osteocalcin than did fillies at 199.6 ± 30.2 ng/mL and 93.8 ± 32.4 ng/mL, respectively (P = .04). Thoroughbred foals had higher average serum BALP concentrations than did QH foals, with average values of 260.8 ± 13.4 U/L and 205.1 ± 18.5 U/L, respectively (P = .02). No gender differences were seen for serum BALP (P = .48). Serum carboxy-terminal propeptide of Type I procollagen (PICP) concentrations could not be measured in this study because the Metra Biosystems assay for PICP could not be validated.

Introduction

Bone synthesis by the osteoblast can be divided into 3 phases: proliferation, matrix development and maturation, and mineralization.¹ Gene expression of type I collagen takes place during the proliferation of the osteoblast cells. The expression of bone specific alkaline phosphatase (BALP) reaches its maximum during matrix maturation and declines as matrix mineralization starts. The osteocalcin gene is expressed during matrix mineralization.When type I collagen is produced as procollagen and released into the extracellular space, the amino and carboxyterminal propeptides of type I procollagen (PINP and PICP, respectively) are cleaved off.² Serum PICP has been shown to be a good marker for bone formation in metabolic bone diseases.³ In Thoroughbred fillies, PICP has an inverse relationship with age, with highest values found in animals less than 1 year of age.⁴ Serum alkaline phosphatase (ALP) has been measured in the young foal and is highest at birth, decreasing to a constant level by 2 months of age.^{5, 6 and 7} Serum BALP constitutes 60% to 92% of the total serum ALP in the horse and is highest in the foal.^{4 and 8} As the foal matures, there is an inverse relationship between age and serum BALP.^{4 and 9} Serum osteocalcin in foals less than 6 months of age has not been reported as having the same age-related pattern as serum BALP.¹⁰However, younger horses have higher serum osteocalcin values than mature horses.^{11, 12 and 13} Davicco et al¹⁴ showed plasma osteocalcin age-related changes for Thoroughbred foals with radioimmunoassay (RIA). Plasma osteocalcin was low at birth, increased to day 8, and then dropped to day 15. The objective of this study was to establish normal ranges and age-related changes in serum BALP, PICP, and osteocalcin in the foal with enzyme-linked immunospecific assays (ELISAs).

Materials and methods

Four Quarter Horse (QH; 2 fillies and 2 colts) and 9 Thoroughbred (3 fillies and 6 colts) foals were included in the study from birth through 112 days of age. Foals were born from February 5 to May 13, 1998. Mares and foals were housed on 40 acres of Bahiagrass (Paspalum notatum) pasture and fed a 15% crude protein (as fed) sweet feed. Body scores were recorded every 28 days on a scale from 1 to 9.¹⁵ Concentrate was fed to each mare at 1.5 kg/100 kg body weight daily and was increased by 20% for each body condition score below 5 and decreased by 20% for each body condition score above 5. Mares were individually fed in 3.6 × 3.6—m stalls twice daily, with foals allowed access to the mares feed. Trace mineral salt blocks were available in the pastures. Water was available at all times.Blood was collected from foals between 10 and 14 hours after birth on day 1. Blood then was collected on days 3, 6, 9, 12, 15, 18, 21, 28, 35, 42, 49, 56, 70, 84, 98, and 112 after morning feedings. Except for day 1, all blood samples were collected between 7:00 and 9:00 am. All blood samples were collected with jugular venipuncture into a glass vacutainer containing no additives or anticoagulants and were allowed to clot. Serum was separated and frozen at −20°C within 4 hours of collection. All samples were analyzed within 6 months of collection.The Alkphase-B immunoassay for the determination of BALP (Metra Biosystems, Mountainview, Calif) and the NovoCalcin immunoassay for determination of osteocalcin (Metra Biosystems), used in this study, have been previously validated in the horse.^{16 and 17} The Prolagen-C immunoassy for determination of the PICP (Metra Biosystems) has not been previously validated in the horse.¹⁷Serum bone metabolism marker raw data were analyzed with analysis of variance with repeated measures over time with gender and breed in the model. Analyses were performed with Statistical Analysis System with proc glm for the analysis of variances.¹⁸

Results

Average serum osteocalcin concentration for the testing period was higher for Thoroughbred than QH foals: 152.1 ± 4.6 and 131.3 ± 6.3 ng/mL (mean ± standard error), respectively (P = .01). No overall differences were seen for gender (P = .10). However, on day 1, colts had higher osteocalcin concentrations than did fillies at 199.6 ± 30.2 ng/mL and 93.8 ± 32.4 ng/mL (P = .04; Fig 1).

Estimation of bone mineral density and breaking strength of laying hens based on scans of computed tomography for body composition analysis

1. The objective of this study was to evaluate the prediction potential of a computer tomography (CT) data collection protocol for determining total body composition used for analysis of tibiotarsal bone quality features.

2. The CT image acquisition was performed on 54 healthy TETRA SL genotype laying hens at 90 weeks of age as well as in the 69th week of the egg production period in vivo and their tibiotarsal bones, ex vivo.

3. Breaking strengths and ash content of the tibiotarsal bones were estimated based on the calculated mineral density of skeletal and tibiotarsal bones by means of CT with an estimation accuracy R² 0.963 and 0.975, respectively.

4. In conclusion, the current investigation demonstrated that the acquisition protocol of CT for total-body composition analysis has a good potential for measuring the mineral status and breaking strength of the reference bone in laying hen.     

Bone mineral density and bone mineral content of the bilateral first phalanges of the thoracic limbs in horses

The bone mineral density (BMD) and the bone mineral content (BMC) in the bone tissue of the bilateral first phalanges of horses' thoracic limbs were analysed. The research material consisted of isolated pastern bones derived from 22 horses. The research was conducted with the use of a Norland model Excell Plus densitometer (Fort Atkinson WI, USA), using affinited beam X-ray technology and an animal research programme (Research Scan, 3.9.6. version) at the following parameters: scanning resolution of 1.5 x 1.5 mm, scanning speed 60 mm/s. The differences between BMC and BMD values in bilateral first phalanges in the thoracic limbs in horses were found to be nonsignificant. It also appeared that there are statistically significant positive correlations between values of the left and right bone of both analysed variables.     

Effect of two microbial phytases on mineral availability and retention and bone mineral density in low-phosphorus diets for broilers

1. The efficacy of supplementation of a low-phosphorus (low-P) maize–soyabean meal diet for broiler chickens with two different microbial (fungal and bacterial) phytases was examined.

2. Broiler chickens received a low-P maize–soyabean meal diet containing either no phytase or one of the two phytases included at one and two times the manufacturer's recommended inclusion level for 21 d.

3. Titanium dioxide was included in the diets as an indigestible marker. Excreta were collected quantitatively from d 18 to 21, and at the end of the study the birds were killed and ileal digesta and leg bone samples collected.

4. No differences were observed for body weight gain and feed intake or apparent metabolisable energy (AME) among all dietary treatment groups.

5. Dietary phytase supplementation improved the apparent retention of Ca, Na and Cu and ileal phytate P absorption from 32% to 44% across inclusion levels.

6. Bone mineral density (BMD) was improved for both phytases across inclusion levels by, on average, 9% for the tibia and 13% for the femur.

7. Dietary phytase supplementation of the low-P diet improved apparent ileal digestibility of serine, glycine, valine, isoleucine, tyrosine, histidine, lysine and arginine.

8. When the results from the present study were combined with the results from other similar published studies and analysed statistically, factors such as dietary P and Ca concentration, as well as bird breed and age, rather than the type or activity of microbial phytase, had the greatest impact on the extent to which dietary supplementation improved P and Ca retention.

9. More work is required to explain the interrelationships between the multiple factors influencing the efficacy of phytase on the availability of dietary minerals.     

Evaluation of subchondral bone mineral density associated with articular cartilage structure and integrity in healthy equine joints with different functional demands

OBJECTIVE: To determine and correlate subchondral bone mineral density and overlying cartilage structure and tensile integrity in mature healthy equine stifle (low magnitude loading) and metacarpophalangeal (high magnitude loading) joints. ANIMALS: 8 healthy horses, 2 to 3 years of age. PROCEDURE: Osteochondral samples were acquired from the medial femoral condyle (FC) and medial trochlear ridge (TR) of the stifle joint and from the dorsal (MC3D) and palmar (MC3P) aspects of the distal medial third metacarpal condyles of the metacarpophalangeal joint. Articular cartilage surface fibrillation (evaluated via India ink staining) and tensile biomechanical properties were determined. The volumetric bone mineral density (vBMD) of the underlying subchondral plate was assessed via dual-energy x-ray absorptiometry. RESULTS: Cartilage staining (fibrillation), tensile moduli, tensile strength, and vBMD were greater in the MC3D and MC3P locations, compared with the FC and TR locations, whereas tensile strain at failure was less in MC3D and MC3P locations than FC and TR locations. Cartilage tensile moduli correlated positively with vBMD, whereas cartilage staining and tensile strain at failure correlated negatively with vBMD. CONCLUSIONS AND CLINICAL RELEVANCE: In areas of high joint loading, the subchondral bone had high vBMD and the articular cartilage surface layer had high tensile stiffness but signs of structural wear (fibrillation and low failure strain). The site-dependent variations and relationships in this study support the concept that articular cartilage and subchondral bone normally adapt to physiologic loading in a coordinated way.     

Mild exercise early in life produces changes in bone size and strength but not density in proximal phalangeal, third metacarpal and third carpal bones of foals

Exercise or lack of it in early life affects chondro-osseous development. Two groups of horses were used to investigate the effects of age and exercise regimen on bone parameters of diaphyseal, metaphyseal, epiphyseal and cuboidal bones of the distal limb of Thoroughbreds. One group had exercised only spontaneously from an early age at pasture (PASTEX group), while the other group of horses were exposed to a 30% greater workload through additional defined exercise (CONDEX). Longitudinal data from peripheral quantitative computed tomography (pQCT) were obtained from eight scan sites of the left forelimb (proximal phalangeal (P_p; 1 site), third metacarpal (Mc3; six sites) and third carpal (C₃; one site) bones) of 32 Thoroughbred foals scanned five times from ∼3 weeks to 17 months of age. The primary outcome measures were bone mineral content (BMC), bone area (BA), and periosteal circumference (Peri C) in diaphyseal bone, with cortical thickness (CortTh), volumetric bone mineral density (BMD_v) and a bone strength index (SSI) also being analysed.At the P_p site within the model there was a significant effect (P = 0.00–0.025) of conditioning exercise increasing bone parameters, except endosteal circumference (Endo C) and BMD_v. The BMC, BA, and SSI of P_p were significantly greater in the CONDEX than PASTEX groups at 12 and 17 months (P = 0.015–0.042) and CortTh at 17 months (P = 0.033). At the M55 site of Mc3 BMC, BA and SSI (P = 0.02–0.04), and at the M33 site, SSI (P = 0.05) were higher in the CONDEX than PASTEX group. The adaptive responses, consistent with diaphyseal strengthening, were more marked in the diaphysis of P_p than Mc3. In the Mc3, metaphysis, trabecular BMD_v was less in the CONDEX than PASTEX group, associated with greater bone mineral accretion in the outer cortical-sub-cortical bone in the CONDEX group. There were no significant between-group differences in any epiphyseal or cuboidal bone parameter. Although the early imposed exercise regimen was not intensive, it had significant effects on diaphyseal bone strength, through change in size but not bone density.     

Maternal low-protein diet affects bone mass and mineral metabolism in suckling rats

This study was performed to analyse the effects of low-protein diet (7%) on bone mass and mineral metabolism in rat pups whose mothers were submitted to protein-restricted diet during late pregnancy and early post-natal periods. For this purpose, 12 pregnant Wistar rats were divided into two groups of six animals each: a control group with free access to standard diet (20% protein) and protein-restricted group (PR) fed with low-protein diet (7% protein) from the 14th day of pregnancy until day 14 after delivery. Body weight, femur bone mass, plasma thyroid hormones (FT₄ and FT₃), biochemical bone marker levels [alkaline phosphatase (ALP), tartrate-resistant acid phosphatase (ACP)] and bone DNA content were recorded. In undernourished pups, a decrease in body weight (−47%, p < 0.001) in skeletal growth (−11%, p < 0.001) and in bone DNA content (−48%, p < 0.001) were observed. Plasma protein and albumin levels and thyroid status were also decreased in undernourished rat pups compared with those of control group. The circulating amino acid levels were decreased in pups. While in their mothers, some of them were increased and the others were decreased. A positive correlation was observed between bone mass and plasma thyroid hormone levels and ALP activity and plasma protein levels, and a negative correlation with ACP activity. Plasma ALP levels were decreased by 19%, whereas plasma tartrate-resistant ACP levels were increased by 33% indicating a hyperactivity of bone remodelling. These results showed that protein-restricted diet given to mothers during late pregnancy and early post-natal periods induced changes in body weight, skeletal growth and bone metabolism in their offspring.     

Supplementary biotin decreases tibial bone weight,density and strength in riboflavin-deficient starter diets for turkey poults

1. Growth and skeletal responses to different dietary concentrations of riboflavin and biotin were compared in turkey poults from hatch to 21 d of age. The birds were fed on a turkey starter diet with different concentrations of supplementary riboflavin (0, 20 and 40 mg/kg) and biotin (0, 0.3 and 0.6 mg/kg) in a factorial design.

2. Poults fed on diets with no supplementary riboflavin had poor gait scores, decreased times to sit and higher rates of culling compared to poults fed on the control diet (20 mg biotin and 0.3 mg riboflavin/kg diet). Histologically, riboflavin deficiency was associated with a peripheral neuropathy similar to that described previously in chicks and, unexpectedly, in growth plate abnormalities.

3. Tibiae of poults fed on the control diet were larger, more dense, stronger and stiffer than the diets with no supplementary riboflavin.

4. Increasing supplementary biotin in poults fed on diets with no supplementary riboflavin was associated with a decrease in tibia weight, density, strength and stiffness.

5. The results demonstrated that riboflavin deficiency in fast-growing turkey poults was associated with growth retardation, growth plate disturbance and peripheral nerve dysfunction leading to an inability to walk.     

Parathyroid hormone (1-34) improves bone mineral density and glucose metabolism in Spontaneously Diabetic Torii-Lepr(fa) rats

The Spontaneously Diabetic Torii-Lepr(fa) (SDT-fa/fa) rat, a model of obese type 2 diabetes, shows obesity, hyperglycaemia and low bone mineral density (BMD). The objective of this study is to evaluate the effects of parathyroid hormone (1-34) [PTH(1-34)] on BMD and glucose metabolism in the SDT-fa/fa rat. SDT-fa/fa rats showed obesity with hyperglycaemia and decreased serum osteocalcin levels and the tibial BMD. A 4-week treatment of PTH(1-34) (20 μg/kg/day) increased the serum osteocalcin levels and the tibial BMD, and decreased the serum glucose levels without changing the serum insulin levels. These findings indicate that PTH(1-34) improved not only BMD but also glucose metabolism in SDT-fa/fa rats. This study suggests that PTH(1-34) is a novel agent for the treatment of diabetic osteoporosis.