Dual-energy X-ray Absorptiometry Research Articles

Prevalence and Clinical Implications of Osteosarcopenia in Patients with Acute Stroke: A Cross-sectional Study.

To investigate the prevalence and risk factors of osteosarcopenia in patients with acute stroke. Overall, 224 patients within 2 weeks of having a stroke were enrolled. Demographic characteristics, National Institutes of Health Stroke Scale (NIHSS), modified Rankin Scale (mRS), modified Barthel Index (MBI), Functional Ambulation Category (FAC), Berg Balance Scale (BBS), and handgrip strength were recorded. Body composition was evaluated using dual-energy X-ray absorptiometry. Patients who met the diagnostic criteria for osteoporosis and sarcopenia were defined as having osteosarcopenia. The overall prevalence of osteoporosis and sarcopenia was 46.9% and 50.9%, respectively. The prevalence of osteoporosis without sarcopenia, sarcopenia without osteoporosis, and osteosarcopenia was 18.3%, 22.3%, and 28.6%, respectively. The proportion of female sex (71.9%), median age, and NIHSS score were significantly higher, and mRS, BBS, MBI, FAC, and grip strength were significantly lower in patients with osteosarcopenia. Older age (≥65-years) (OR, 15.4), female sex (OR, 6.23), and lower BMI (<25 kg/m 2 ) (OR, 43.13) were independently associated with the likelihood of osteosarcopenia. Osteosarcopenia may occur in acute stroke survivors. Patients with osteosarcopenia have a significantly higher stroke severity and disability. A comprehensive diagnostic approach is imperative for osteosarcopenia, thereby facilitating implementation of optimal rehabilitative strategies.

Body weight and composition endpoints in cancer cachexia clinical trials: Systematic Review 4 of the cachexia endpoints series.

Significant variation exists in the outcomes used in cancer cachexia trials, including measures of body composition, which are often selected as primary or secondary endpoints. To date, there has been no review of the most commonly selected measures or their potential sensitivity to detect changes resulting from the interventions being examined. The aim of this systematic review is to assess the frequency and diversity of body composition measures that have been used in cancer cachexia trials. MEDLINE, Embase and Cochrane Library databases were systematically searched between January 1990 and June 2021. Eligible trials examined adults (≥18years) who had received an intervention aiming to treat or attenuate the effects of cancer cachexia for >14days. Trials were also of a prospective controlled design and included body weight or at least one anthropometric, bioelectrical or radiological endpoint pertaining to body composition, irrespective of the modality of intervention (e.g., pharmacological, nutritional, physical exercise and behavioural) or comparator. Trials with a sample size of <40 patients were excluded. Data extraction used Covidence software, and reporting followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidance. This review was prospectively registered (PROSPERO: CRD42022276710). A total of 84 clinical trials, comprising 13016 patients, were eligible for inclusion. Non-small-cell lung cancer and pancreatic cancer were studied most frequently. The majority of trial interventions were pharmacological (52%) or nutritional (34%) in nature. The most frequently reported endpoints were assessments of body weight (68 trials, n=11561) followed by bioimpedance analysis (BIA)-based estimates (23 trials, n=3140). Sixteen trials (n=3052) included dual-energy X-ray absorptiometry (DEXA)-based endpoints, and computed tomography (CT) body composition was included in eight trials (n=841). Discrepancies were evident when comparing the efficacy of interventions using BIA-based estimates of lean tissue mass against radiological assessment modalities. Body weight, BIA and DEXA-based endpoints have been most frequently used in cancer cachexia trials. Although the optimal endpoints cannot be determined from this review, body weight, alongside measurements from radiological body composition analysis, would seem appropriate. The choice of radiological modality is likely to be dependent on the trial setting, population and intervention in question. CT and magnetic resonance imaging, which have the ability to accurately discriminate tissue types, are likely to be more sensitive and provide greater detail. Endpoints are of particular importance when aligned with the intervention's mechanism of action and/or intended patient benefit.

Dapagliflozin added to metformin reduces perirenal fat layer in type 2 diabetic patients with obesity

Sodium-glucose co-transporters type 2 inhibitors (SLGT2i) are highly effective in controlling type 2 diabetes, but reported beneficial cardiovascular effects suggest broader actions on insulin resistance. Weight loss may be initially explained by glycosuria-induced net caloric output and secondary volumetric reduction, but its maintenance could be due to loss of visceral fat mass. Structured ultrasound (US) imaging of abdominal adipose tissue (“eco-obesity”) is a recently described methodology used to measure 5 consecutive layers of abdominal fat, not assessable by DEXA or CT scan: superficial subcutaneous (SS), deep subcutaneous (DS), preperitoneal (PP), omental (Om) and right perirenal (RK). PP, Om and RK are predictors of metabolic syndrome (MS) with defined cut-off points. To assess the effect of SLGT2i on every fat depot we enrolled 29 patients with type 2 Diabetes (HbA1c 6.5–9%) and Obesity (IMC > 30 kg/m2) in an open-label, randomized, phase IV trial (EudraCT: 2019-000979-16): the Omendapa trial. Diabetes was diagnosed < 12 months before randomization and all patients were treatment naïve. 14 patients were treated with metformin alone (cohort A) and 15 were treated with metformin + dapaglifozin (cohort B). Anthropometric measures and laboratory tests for glucose, lipid profile, insulin, HOMA, leptin, ultrasensitive-CRP and microalbuminuria (MAL) were done at baseline, 3rd and 6th months. At 6th month, weight loss was −5.5 ± 5.2 kg (5.7% from initial weight) in cohort A and −8.4 ± 4.4 kg (8.6%) in cohort B. Abdominal circumference showed a −2.7 ± 3.1 cm and −5.4 ± 2.5 cm reduction, respectively (p = 0.011). Both Metformin alone (−19.4 ± 20.1 mm; −21.7%) or combined with Dapaglifozin (−20.5 ± 19.4 mm; −21.8%) induced significant Om fat reduction. 13.3% of cohort A patients and 21.4% of cohort’s B reached Om thickness below the cut-off for MS criteria. RK fat loss was significantly greater in cohort B group compared to cohort A, at both kidneys. Only in the Met + Dapa group, we observed correlations between Om fat with leptin/CRP/MAL and RK fat with HOMA-IR. US is a useful clinical tool to assess ectopic fat depots. Both Metformin and Dapaglifozin induce fat loss in layers involved with MS but combined treatment is particularly effective in perirenal fat layer reduction. Perirenal fat should be considered as a potential target for cardiovascular dapaglifozin beneficial effects.

Associations between the composite dietary antioxidant index and abdominal aortic calcification among United States adults: A cross-sectional study.

Oxidative stress has previously been shown to play a pivotal role in the pathogenesis of vascular calcification. In the present study, we aimed to investigate the association between the composite dietary antioxidant index (CDAI) and abdominal aortic calcification (AAC). We conducted a cross-sectional study of United States adults using data from the 2013-2014 National Health and Nutrition Examination Survey. The CDAI was calculated from vitamins A, C, E, selenium, zinc, and caretenoid through two rounds of 24-h dietary recall interviews. AAC was assessed by a lateral dual-energy x-ray absorptiometry scan of the thoraco-lumbar spine. The association between CDAI and AAC was evaluated with weighted multivariable logistic regression. Overall, an unweighted 1081 participants were analyzed, including 110 with AAC and 971 without AAC. In the multivariable fully adjusted logistic regression model, CDAI was significantly associated with AAC (odds ratio = 0.89, 95% CI 0.81-0.98; P = 0.02). Compared with the lowest quartile, the highest quartile of CDAI was related to a 0.33-fold risk of AAC (95% CI 0.12-0.90; P = 0.03). Subgroup analysis showed that the significant association between CDAI and AAC was only observed in participants without hypertension (P for interaction = 0.002). A higher CDAI was associated with a lower prevalence of AAC among adults without hypertension in the US. Further large-scale prospective studies are required to analyze the protective role of the CDAI in AAC progression.

Long-Term Bone Mineral Density Changes in Kidney Transplant Recipients Treated with Denosumab: A Retrospective Study with Nonequivalent Control Group.

Data on the effectiveness of denosumab on osteoporosis after kidney transplantation are limited. We investigated the long-term bone mineral density (BMD) changes in kidney transplant recipients (KTRs) treated with denosumab compared to untreated KTRs. We enrolled KTRs treated with denosumab 60mg/6 months for 4years. An untreated group of sex and age-matched KTRs with a 1:1 ratio was included. The primary outcome was BMD changes assessed by Dual-energy X-ray Absorptiometry over 4 years. Data on serum creatinine, alkaline phosphatase (ALP), parathyroid hormone, and 25-hydroxyvitamin D were collected. All patients received oral cholecalciferol and calcium supplementation. 23 denosumab-treated KTRs were enrolled, and 23 untreated KTRs. The median time from transplant to the start of denosumab was 4years (range 0:24). The denosumab group showed a significant increase from baseline in BMD at the lumbar spine (LS) (9.0 ± 10.7%, p < 0.001), and total hip (TH) (3.8 ± 7.9%, p = 0.041). The untreated group showed a significant decrease at all sites (- 3.0 ± 7%, p = 0.041 at the LS; - 6.3 ± 9.2%, p = 0.003 at the TH; - 6.7 ± 9.3%, p = 0.003 at the FN). The between-group differences in percent BMD changes were statistically significant at all sites. Similar results were found for the respective Z-scores. The ALP serum levels significantly decreased from baseline only in the denosumab group, with a significant between-group difference (p = 0.032). No significant differences in serum creatinine, hypocalcaemic events or acute graft rejection rates were observed. Four years of denosumab therapy were associated with increased BMD in KTRs, while untreated KTRs showed significant BMD losses at all sites.

Bone health and awareness of osteoporosis in women aged 40 to 60 years in Jiaxing City, China.

The objective of this study is to evaluate the pattern of bone mineral density (BMD) in native Jiaxing women, and to investigate their awareness of osteoporosis. A total of 538 native Jiaxing women aged 40 to 60 years were recruited from January 2022 to December 2023 when they had routine examinations in the physical examination center of Jiaxing Maternal and Child Health Hospital. The Chinese version of Osteoporosis Prevention and Cognition Tool was used to evaluate participants' cognitive level of osteoporosis. BMD of participants' lumbar spine (L1-L4) and left hip (Neck/Troch/Ward) was measured by dual-energy X-ray absorptiometry. The mean total score of the awareness about osteoporosis (general knowledge, complications, and prevention) was 22.08 ± 2.74, which was suboptimal. The higher the education level, the higher the score of awareness (P < .01). Medical staff had the highest awareness rate of osteoporosis and the farmer had the lowest. Lumber spine and hip BMD of all sites was significantly decreased with increasing age (P < .001). Premenopausal women had higher BMD than postmenopausal women at all lumbar spine and hip sites (P < .01). The overall frequency of osteoporosis was 10.8% in the lumbar spine, 8.6% in the total hip, and 17.7% in either site. Osteoporosis and osteopenia are highly prevalent among native Jiaxing women but their awareness of osteoporosis is inadequate. To reduce the prevalence of osteoporosis, especially among the unemployed, we should carry out effective health education through multimedia to raise their awareness of osteoporosis. In addition, menopausal hormone therapy should also be considered in menopausal women.

The efficacy and safety of leucine-enriched essential amino acids in knee osteoarthritis patients: A randomized controlled trial.

Supplementation with leucine-enriched essential amino acids (LEAAs) has shown efficacy in the recovery of muscle injury and activation of muscle synthesis. Muscle function in knee osteoarthritis is a crucial factor for managing pain and preserving ambulatory function. However, the efficacy and safety of LEAAs supplementation in patients with knee osteoarthritis have not been evaluated. In this prospective analysis, we evaluated the efficacy and safety of supplementation with 12 g of LEAAs daily for 8 weeks in knee-symptomatic osteoarthritis patients. For assessing the efficacy, clinical pain, calf circumference, and disability were assessed using questionnaires (visual analog scale, Knee Society Score, and 36-item short form survey [SF-36]), laboratory analyses (total protein and albumin), and radiologic study (dual-energy X-ray absorptiometry [DEXA]) for muscle and bone density. To evaluate safety, generalized or localized protein allergic reactions, complete blood count, liver and kidney function, and serum glucose were measured. Sixty-five participants, categorized into the experimental (n = 32) and control (n = 33) groups, were included in this 8-week trial from March 2022 to July 2022. A significantly higher efficacy was observed in the experimental group than in the control group, as indicated by muscle density in the DEXA scan (P = .001) and SF-36 (P < .001). The safety evaluation revealed no related generalized or local protein allergy. Hematological findings, serum glucose, and kidney and liver toxicity were not significantly different between the groups. Supplementation with leucine-enriched proteins is safe and efficacious in the improvement of muscle density and quality of life.

End-to-End Semi-Supervised Opportunistic Osteoporosis Screening Using Computed Tomography.

Osteoporosis is the most common metabolic bone disease and can cause fragility fractures. Despite this, screening utilization rates for osteoporosis remain low among populations at risk. Automated bone mineral density (BMD) estimation using computed tomography (CT) can help bridge this gap and serve as an alternative screening method to dual-energy X-ray absorptiometry (DXA). The feasibility of an opportunistic and population agnostic screening method for osteoporosis using abdominal CT scans without bone densitometry phantom-based calibration was investigated in this retrospective study. A total of 268 abdominal CT-DXA pairs and 99 abdominal CT studies without DXA scores were obtained from an oncology specialty clinic in the Republic of Korea. The center axial CT slices from the L1, L2, L3, and L4 lumbar vertebrae were annotated with the CT slice level and spine segmentation labels for each subject. Deep learning models were trained to localize the center axial slice from the CT scan of the torso, segment the vertebral bone, and estimate BMD for the top four lumbar vertebrae. Automated vertebra-level DXA measurements showed a mean absolute error (MAE) of 0.079, Pearson's r of 0.852 (P<0.001), and R2 of 0.714. Subject-level predictions on the held-out test set had a MAE of 0.066, Pearson's r of 0.907 (P<0.001), and R2 of 0.781. CT scans collected during routine examinations without bone densitometry calibration can be used to generate DXA BMD predictions.

Patterns of energy availability and carbohydrate intake differentiate between adaptable and problematic low energy availability in female athletes

BackgroundProblematic low energy availability (EA) is the underlying culprit of relative energy deficiency in sport (REDs), and its consequences have been suggested to be exacerbated when accompanied by low carbohydrate (CHO) intakes.ObjectivesThis study compared dietary intake, nutrition status and occurrence of REDs symptoms in groups of female athletes, displaying different patterns of EA and CHO intake.MethodsFemale athletes (n = 41, median age 20.4 years) from various sports weighed and recorded their food intake and training for 7 consecutive days via a photo-assisted mobile application. Participants were divided into four groups based on patterns of EA and CHO intakes: sufficient to optimal EA and sufficient to optimal CHO intake (SEA + SCHO), SEA and low CHO intake (SEA + LCHO), low energy availability and SCHO (LEA + SCHO), and LEA and LCHO (LEA + LCHO). SEA patterns were characterised by EA ≥30 and LEA by EA &amp;lt;30 kcal/kg fat free mass, and SCHO patterns characterised by CHO intake ≥3.0 and LCHO &amp;lt;3.0 g/kg body weight for most of the registered days. Body composition was measured with dual energy x-ray absorptiometry, resting metabolic rate with indirect calorimetry and serum blood samples were collected for evaluation of nutrition status. Behavioural risk factors and self-reported symptoms of REDs were assessed with the Low Energy Availability in Females Questionnaire, Eating Disorder Examination Questionnaire Short (EDE-QS), Exercise Addiction Inventory, and Muscle Dysmorphic Disorder Inventory.ResultsIn total, 36.6% were categorised as SEA + SCHO, of which 5/16 were ball sport, 7/10 endurance, 1/7 aesthetic, 2/5 weight-class, and 0/3 weight-class athletes. Of LEA + LCHO athletes (19.5% of all), 50% came from ball sports. Aesthetic and endurance athletes reported the greatest training demands, with weekly training hours higher for aesthetic compared to ball sports (13.1 ± 5.7 vs. 6.7 ± 3.4 h, p = 0.012). Two LEA + LCHO and one SEA + LCHO athlete exceeded the EDE-QS cutoff. LEA + LCHO evaluated their sleep and energy levels as worse, and both LEA groups rated their recovery as worse compared to SEA + SCHO.ConclusionRepeated exposures to LEA and LCHO are associated with a cluster of negative implications in female athletes. In terms of nutrition strategies, sufficient EA and CHO intakes appear to be pivotal in preventing REDs.

Associations of marrow fat fraction with MR imaging based trabecular bone microarchitecture in first-time diagnosed type 1 diabetes mellitus

PurposeTo determine whether there are alterations in marrow fat content in individuals first-time diagnosed with type 1 diabetes mellitus (T1DM) and to explore the associations between marrow fat fraction and MRI-based findings in trabecular bone microarchitecture.MethodA case-control study was conducted, involving adults with first-time diagnosed T1DM (n=35) and age- and sex-matched healthy adults (n=46). Dual-energy X-ray absorptiometry and 3 Tesla-MRI of the proximal tibia were performed to assess trabecular microarchitecture and vertebral marrow fat fraction. Multiple linear regression analysis was used to test the associations of marrow fat fraction with trabecular microarchitecture and bone density while adjusting for potential confounding factors.ResultsIn individuals first-time diagnosed with T1DM, the marrow fat fraction was significantly higher (p &amp;lt; 0.001) compared to healthy controls. T1DM patients also exhibited higher trabecular separation [median (IQR): 2.19 (1.70, 2.68) vs 1.81 (1.62, 2.10), p &amp;lt; 0.001], lower trabecular volume [0.45 (0.30, 0.56) vs 0.53 (0.38, 0.60), p = 0.013], and lower trabecular number [0.37 (0.26, 0.44) vs 0.41 (0.32, 0.47), p = 0.020] compared to controls. However, bone density was similar between the two groups (p = 0.815). In individuals with T1DM, there was an inverse association between marrow fat fraction and trabecular volume (r = -0.69, p &amp;lt; 0.001) as well as trabecular number (r = -0.55, p &amp;lt; 0.001), and a positive association with trabecular separation (r = 0.75, p &amp;lt; 0.001). Marrow fat fraction was independently associated with total trabecular volume (standardized β = -0.21), trabecular number (β = -0.12), and trabecular separation (β = 0.57) of the proximal tibia after adjusting for various factors including age, gender, body mass index, physical activity, smoking status, alcohol consumption, blood glucose, plasma glycated hemoglobin, lipid profile, and bone turnover biomarkers.ConclusionsIndividuals first-time diagnosed with T1DM experience expansion of marrow adiposity, and elevated marrow fat content is associated with MRI-based trabecular microstructure.

Investigating the effects of synbiotic supplementation on functional movement, strength and muscle health in older Australians: a study protocol for a double-blind, randomized, placebo-controlled trial

BackgroundAging has been associated with a progressive loss of skeletal muscle quality, quantity and strength, which may result in a condition known as sarcopenia, leading to a decline in physical performance, loss of independence and reduced quality of life. While the cause of impaired physical functioning observed in elderly populations appears to be multifactorial, recent evidence suggests that age-associated alterations in gut microbiota could be a contributing factor. The primary objective will be to assess the effects of a dietary synbiotic formulation on sarcopenia-related functional outcomes such as handgrip strength, gait speed and physical performance within older individuals living independently. The secondary objective will be to examine associations between changes in gut microbiota composition, functional performance and lean muscle mass.MethodsSeventy-four elderly (60–85 years) participants will be randomized in a double-blind, placebo-controlled fashion to either an intervention or control group. The intervention group (n = 37) will receive oral synbiotic formulation daily for 16 weeks. The control group (n = 37) will receive placebo. Assessments of physical performance (including Short Physical Performance Battery, handgrip strength and timed up-and-go tests) and muscle ultrasonography will be performed at 4 time points (baseline and weeks 8, 16 and 20). Likewise, body composition via bioelectric impedance analysis and blood and stool samples will be collected at each time point. Dual-energy X-ray absorptiometry will be performed at baseline and week 16. The primary outcomes will be between-group changes in physical performance from baseline to 16 weeks. Secondary outcomes include changes in body composition, muscle mass and architecture, fecal microbiota composition and diversity, and fecal and plasma metabolomics.DiscussionGut-modulating supplements appear to be effective in modifying gut microbiota composition in healthy older adults. However, it is unclear whether these changes translate into functional and/or health improvements. In the present study, we will investigate the effects of a synbiotic formulation on measures of physical performance, strength and muscle health in healthy older populations.Trial registrationThis study was prospectively registered with the Australian New Zealand Clinical Trials Registry (ACTRN12622000652774) in May 2022.

Evaluating the effects of hormone therapy termination on skeletal muscle and physical independence in postmenopausal women.

In women, the age-related decline in skeletal muscle structure and function is accelerated after menopause, which implicates the role of decreased circulating estrogen levels. Indeed, boosting estrogen, by means of postmenopausal hormone therapy (HT), generally proves beneficial to skeletal muscle. The evidence regarding whether these benefits persist even after cessation of HT is limited, nor is it clear how physical behavior (PB) impacts on benefits. Hence, this exploratory study focused on the interplay between HT administration/cessation, PB and in vivo skeletal muscle structure and function. Fifty healthy women (≥60 y) were included; 19 had an HT administration history (≥9 mo, with now ~8-y hiatus in treatment) and 31 no such history. On seven continuous days, PB data were collected using triaxial accelerometry and analyzed using compositional data analysis. Gastrocnemius medialis muscle volume, architecture, and function were determined using ultrasonography, electromyography, dual x-ray absorptiometry, and dynamometry. Current serum estradiol levels were measured using ELISA. Only fascicle length and duration of HT administration were positively associated. With respect to PB levels, we found a pattern suggesting greater vitality (higher physical activity and lower sedentarism) in previous HT users, compared with nonusers, despite the two groups currently no longer exhibiting significantly different levels of circulating estradiol. After an 8-year hiatus in treatment, HT provides limited advantages in gastrocnemius medialis muscle properties. Interestingly, it perhaps enhances vitality despite prolonged cessation, which in the longer term would facilitate greater physical independence, especially considering the association of sedentary behavior with greater frailty.

Diagnostic discordance of osteoporosis in acromegaly: a comparison of quantitative computed tomography and dual-energy X-ray absorptiometry

Diagnostic discordance of osteoporosis in acromegaly: a comparison of quantitative computed tomography and dual-energy X-ray absorptiometry

Cross-sectional associations between accelerometer-measured physical activity and hip bone mineral density. The Tromsø study 2015–2016

Cross-sectional associations between accelerometer-measured physical activity and hip bone mineral density. The Tromsø study 2015–2016

Associations of Plasma and Fecal Metabolites with Body Mass Index and Body Fat Distribution in Children.

Childhood obesity continues to be a critical public health concern with far-reaching implications for the well-being. This study aimed to investigate the association between metabolites in plasma and feces and indicators including body mass index (BMI), BMI for age Z score (BMIZ), and body fat distribution among children aged 6-9 years in China. This cross-sectional study enrolled 424 healthy children, including 186 girls and 238 boys. Dual-energy X-ray absorptiometry (DXA) was used to determine the body fat content and regional fat distribution. Plasma and fecal metabolites were analyzed using targeted metabolomic technologies. A total of 200 plasma metabolites and 212 fecal metabolites were accurately quantified via ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). By using Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) and random forest model, we discovered that 9 plasma metabolites and 11 fecal metabolites were associated with different weight statuses. After adjusting for potential covariates and false discovery rate (FDR) correction, multiple linear regression analyses revealed that plasma metabolites (fumaric acid, glycine, l-glutamine, methylmalonic acid, and succinic acid) and fecal metabolites (protocatechuic acid) were negatively associated (β: -1.373--0.016, pFDR: <0.001-0.031; β: -1.008--0.071, pFDR: 0.005-0.033), while plasma metabolites (isovaleric acid, isovalerylcarnitine, l-glutamic acid, and pyroglutamic acid) and fecal metabolites (3-aminoisobutanoic acid, butyric acid, N-acetylneuraminic acid, octanoylcarnitine, oleoylcarnitine, palmitoylcarnitine, stearoylcarnitine, taurochenodesoxycholic acid, and taurodeoxycholic acid) exhibited positive associations with BMI, BMIZ, and body fat distribution (β: 0.023-2.396, pFDR: <0.001; β: 0.014-1.736, pFDR: <0.001-0.049). Plasma and fecal metabolites such as glutamine may serve as a potential therapeutic target for the development of obesity.

261 Relationship between dietary calcium and available phosphorus in growing pigs

Abstract The amount of and relationship between dietary total calcium (tCa) and available phosphorus (avP) are critical for lean and bone growth in pigs. Our objective was to evaluate the relationship between tCa and avP in nursery-grower pigs. Mixed sex pigs [n = 117; initial body weight (BW) = 11 ± 0.17 kg] were blocked by BW to individual pens and assigned to 1 of 18 dietary treatments (n = 6 to 7 pigs/trt). Treatments were divided into 4 titrations containing 5 treatments each. Each titration had the same tCa:avP of 1.52, 1.77, 2.12, 2.64, and 3.50. In titration 1(T1), tCa was set at NRC recommendation of 0.68% and avP ranged from 0.46 to 0.20%. Titration 2(T2), tCa was set at 14% below NRC recommendation at 0.56% and avP ranged from 0.38 to 0.16%. Titration 3(T3), avP was set at NRC recommendation of 0.33% and tCa ranged from 0.49 to 1.12%. In titration 4(T4), avP was set at 0.26% with tCa ranging from 0.39 to 0.90%. Pig BW and feed disappearance were recorded at the beginning and the end to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency gain to feed ratio (G:F) performance parameters over the 40-d study duration. Thereafter, whole body, femur, and 3rd metatarsal bone mineral density (BMD) and contents (BMC) were measured using a dual-energy X-ray absorptiometry (DXA). Within each titration, data were analyzed with pig as the experimental unit, random effect of block and the fixed effect of diet. In T1, performance parameters did not differ (P &amp;gt; 0.10). However, body BMD decreased (0.843, 0.841, 0.804, 0.706, and 0.585 g/cm2) as tCa:avP increased (P &amp;lt; 0.001). In T2, as tCa:avP increased, ADG decreased (0.85, 0.85, 0.77, 0.73, and 0.67 kg/d; P &amp;lt; 0.001). Similarly, whole body BMD decreased as tCa:avP increased (0.800, 0.803, 0.668, 0.616, and 0.558 g/cm2; P &amp;lt; 0.001). ADG, ADFI and whole and individual BMC did not differ in T3 and T4. Consequentially, body BMD ranged from 0.756 to 0.808 g/cm2 in T3 and 0.656 to 0.703 g/cm2 in T4. Breakpoint analysis reported tCa:avP of 2.321 and 1.849 or less was optimal for BMD in T1 and T2, respectively. No optimal breakpoints could be determined for whole BMD within T3 and T4. Breakpoint analysis for ADG reported tCa:avP of 2.311 and 2.341 or less was optimal in T2 and T3, respectively. No optimal breakpoints could be determined for ADG within T1 and T4.

257 Estimating bone mineral replenishment following phosphorus deficiency in growing pigs

Abstract Available phosphorus (avP) is essential for bone health and strength in growing pigs. Our objective was to evaluate growth performance and replenishment of bone mineral in avP deficient pigs when fed diets adequate in avP. Over a 42-d test period, mixed sex pigs [n = 48; initial body weight (BW) = 13.1 ± 0.7 kg], were randomly assigned to one of three dietary treatments consisting of two experimental periods. In period 1(28 d), 8 pens/trt (2 pigs/pen) were fed diets formulated to 0.36, 0.17 and 0.08% avP and at a total calcium to avP ratio of 2.91, 3.15 or 6.40, respectively, representing adequate, marginally deficient, or deficient avP. In period 2 (14 d), marginally deficient and deficient pigs were then fed diets formulated to be above requirement at 0.54% avP and a 2.19 Ca:avP, while the adequate pigs staying on the same period 1 diet (n = 8 pens/trt). Pig BW and pen feed disappearance were recorded during each phase to calculate average daily gain (ADG), average daily feed intake (ADFI) and feed efficiency gain to feed (G:F). At the end of each period, 1 pig per pen was removed to assess whole body, femur, and 3rd metatarsal bone mineral content (BMC) and bone mineral density (BMD) via dual-energy X-ray absorptiometry (DXA). All data were analyzed with pen as the experimental unit and the fixed effect of diet within each period. At the end of period 1, adequate avP and marginally deficient fed pigs were heavier than the deficient avP fed pigs (41.9 and 41.2 vs 33.4 kg, respectively, P &amp;lt; 0.001). Consequently, ADG and ADFI were significantly reduced as avP decreased (P &amp;lt; 0.001). Compared with the adequate avP pigs, whole body BMD was reduced by 22% and 65% in marginal and deficient avP pigs (P &amp;lt; 0.001), respectively. At the end of period 2, adequate, marginal, and deficient avP pigs weighed 53.4, 53.2 vs 43.1 kg (P &amp;lt; 0.001), respectively. Within period 2, ADG, ADFI, and G:F did not differ. However, adequate avP fed pigs continued to have a greater body BMD compared with marginal and deficient avP pigs (0.928, 0.850, and 0.732 g/cm2; P &amp;lt; 0.001), respectively. Whole body BMD and BMC increased from period 1 to peiod 2, resulting in period 2 whole body BMC accretion rates of 2.31, 23.28, and 9.30 g/d (P &amp;lt; 0.007) for deficient, marginal, and adequate diets, respectively. In conclusion, pigs fed marginally deficient avP diets reduced body BMD while pigs fed deficient avP diets reduced body BMD and performance. Following this period of deficiency, marginal deficient avP pigs recovered growth and BMC within 14 d when fed increased dietary avP. However, compared with adequate avP fed pigs, the deficient pigs only partially recovered BMC and BW within the 14-d replenishment period.

249 A nutritional solution based on calcidiol (25-OH-D3, HyD) and triterpenoid improves growth performance in grower-finisher pigs fed low Ca and P diets without compromising bone health

Abstract Nutritional strategies to realize the genetic potential of modern pigs without compromising welfare while reducing environmental impact are critical for success in the swine industry today. By harnessing the potential of 25-OH-D3, it is possible to fine-tune mineral utilization, thereby allowing for the reduction of excessive calcium (Ca) and phosphorus (P), while promoting bone development and muscle deposition in finisher pigs [1]. A study was conducted using 60 male pigs [initial body weight (BW) = 29.9 kg ± 0.5 kg] to evaluate the effect of reducing dietary Ca and P and supplementing with 25-OH-D3 and triterpenoid, on growth, bone and blood characteristics. Pigs entered the experimental room at 10 wk of age and were randomly allocated to one of six pens in groups of 10. Pigs had a 2-wk adaptation where they were offered a grower diet (NE:12.3MJ, CP:17.5%) before receiving their respective treatments from 12 wk (NE:11.5MJ, CP:16.19%). Three experimental diets were evaluated for 7 wk; Positive control: 0.7% total Ca, 0.36% total P, vit D3 at 1,500 IU/kg feed (PC), negative control: PC diet + 30% reduced Ca and 10% reduced P (NC), and NC diet with 1,500 IU D3, in calcidiol form (25-OH-D3, HyD) and triterpenoid (NC+). Pigs had ad libitum access to feed which was recorded individually via automated electronic feeders. At slaughter, blood was collected, and body and carcass composition scans were taken from pigs using dual-energy x-ray absorptiometry (DXA) and metacarpals were collected. Data were analyzed in JMP17.0 using one-way ANOVA, including treatment as a main effect and 10-wk weight as a covariate, with pig as the experimental unit. Table 1 shows the results. Pigs offered NC+ tended to have a heavier slaughter weight compared with NC, with PC being intermediate (P = 0.08). There were no differences in feed-intake, but NC+ increased average daily gain compared with NC (P = 0.03), and NC+ tended to be more efficient (P = 0.08). The DXA-scan demonstrated that bone mineral density and content in NC+ pigs were comparable with PC and NC. Additionally, reducing Ca and P in NC resulted in reduced ash, Ca and P in the metacarpals. Interestingly, NC+ had similar bone P content to PC, indicating that NC+ allows for reduced Ca and P, without compromising bone composition. As expected, NC+ had greater 25-OH-D3 blood concentrations (P &amp;lt; 0.001). Although there was no difference in blood for Ca, P concentrations were greater in NC+ compared with other groups (P = 0.007), suggesting that NC+ allowed for greater P circulating concentrations, despite being reduced in the diet. In conclusion, supplementing a reduced Ca and P diet with calcidiol and triterpenoid can enhance weight gain and feed-conversion as well as improving blood 25-OH-D3 and bone P concentrations. The use of this solution shows that diets can be formulated to be more sustainable without compromising performance or bone-health.

127 Utilizing predictive models for bone mineral content and bone mineral density as a tool to assess dietary phosphorous

Abstract Dietary phosphorous is a necessary nutrient for bone development in pigs at all stages of its growing. Deficiencies in phosphorous decrease bone mineral content (BMC) and bone mineral density (BMD) and may be a causative of lameness. However, the normal range expected in whole body (WB) and individual bones for BMC and BMD in commercial pigs has been poorly defined. Therefore, our objectives were to 1) model normal WB bone density at multiple timepoints in wean to finish pigs, and 2) determine the extent to which individual bone (femur and 3rd metatarsal) BMC and BMD could predict WB BMC and BMD. Mixed sex pigs [Camborough (1050) x 337, PIC] were utilized and included freshly weaned ~21 d (n = 8), ~44 d of age (n = 24), ~84 d of age (n = 24) and ~154 d of age (n = 24). Pigs were individually penned. Excluding weaning age, at each age group pigs were randomly assigned to diets adequate, marginally deficient, or deficient in available phosphorus (avP) and fed for 3, 4, and 6 wk (age group 44, 84, 154, respectively). Within each age group, diets were formulated to meet nutrient and energy requirements except for avP and pigs fed ad libitum. On-test and off-test body weight (BW) and feed intake and gain to feed ratio were assessed for each age group. At the end of each feeding period, all pigs were euthanized and WB, femur (F) and 3rd metatarsal (M) BMC and BMD determined by dual X-ray absorptiometry (DXA). Data were analyzed using linear and generalized additive models that predicted response variables (BMC or BMD) as a function of BW or age. Only pigs fed adequate avP diets were used in the model fit. Pigs fed adequate avP diets increased BMD with age (0.22, 0.42, 0.84 and 1.10 g/cm2, days of age 21, 44, 84 and 154 respectively, P &amp;lt; 0.001). Within day of age 84, marginally and deficient avP diets reduced BMC and BMD by 21 to 41% (P = 0.002) and 12 to 25% (P = 0.006), respectively. Within day of age 154, marginally and deficient avP diets reduced BMC and BMD by 9% (P = 0.05) and 6 to 8% (P = 0.06), respectively. Body weight record and individual bone (F and M) BMC and BMD from pigs fed deficient avP diets were used to predict WB BMC and BMD and the mean square error of prediction was selected as a criterion to evaluate the ability of the models to detect these inadequately fed pigs. Using the selected models, pigs fed nutritionally deficient diets were detected due to 2- to 7-fold increase in MSE of predicted WBMD or WBMC compared with pigs fed adequate diets. These models can be used to assess bone development and strength in growing pigs and to infer the adequacy of avP level supplied in their diets.

259 Effect of very low calcium diet supplemented with microbial phytase in post-weaning piglets

Abstract Young piglets have an immature intestine that provides limited gastric acidity to digest nutrients compared with later stages of growth. Food has the intrinsic capacity to modify gastric acidity, particularly in relation to their concentrations of limestone, the ingredient with the greatest capacity to bind to acid. An experiment was conducted to evaluate the impacts of reducing dietary calcium (Ca) by reducing calcium supplementation immediately after weaning; compared with the recommendations of the NRC (2012), in association with phytase supplementation. The treatments were distributed during 3 phases [Phase 1 (P1, d 0-9), 2 (P2, d 10-16) and 3 (P3, d 17-35)]. Treatments were: 1) a diet low Ca that did not contained limestone during phase 1 (LowCa), P1 to P3 respectively, 0.51-0.60-0.65 % Ca and 0.48-0.43-0.38 % standardized ileal digestible P (STTD P), 2), diet 1 with microbial phytase (LowCa+PhytM); P1 to P3 respectively, 0.51-0.60-0.65 % Ca and 0.48-0.43-0.38% STTD P with 750 FTU phytase, and 3) a diet fulfilling requirement (NormalCa+PhytM) P1 to P3 respectively, 0.85-0.80-0.70 % Ca and 0.48-0.43-0.38 % STTD P with 750 FTU phytase. Piglets (n = 120) were allocated to 6 pens of 5 piglets per treatment in function of initial body weight (BW; 6.12 ± 0.028 kg). On d 0, 15 and 36, dual X-ray (DXA) bone densitometry was used to measure body fat, lean and mineral content (BMC) compositions using 8 piglets per treatment. At the end of phase 1 (d 9) a blood sample was collected. Data were analyzed using the SAS MIXED procedure with Tukey’s test to compare means. No differences were observed in growth performance or DXA measurements during the first phase. On d 9, LowCa piglets showed signs of hypocalcaemia with reduced plasma Ca (P = 0.03), increased plasma P (P = 0.02) and a lower Ca:P ratio in plasma (P = 0.04). From d 9-15, piglets that had received LowCa+PhytM showed greater average daily gain (ADG; P = 0.002) while other criteria did not differ between treatments. On d 15, the body composition evaluated by DXA showed no difference among dietary treatments. During phase 3, final BW and average daily feed intake were not modified by dietary treatments, while average daily gain and feed efficiency were greater in LowCa than in NormalCa+PhytM (+7.3 and 6.7%, respectively), and LowCa+PhytM was intermediate. Body composition on d 35 showed no difference among treatments while a tendency (P = 0.095) for greater BMC deposition (g/d) in LowCa in comparison with NormalCa+PhytM (+1.3 %). The implemented LowCa strategy resulted in momentary hypocalcemia which probably activated homeostatic mechanisms allowing piglets to be more efficient in using minerals and possibly other nutrients leading to better growth performance, without impact on bone mineralization.