The accuracy of dual energy X-ray absorptiometry (DXA), weight, and P2 back fat to predict half-carcass and primal-cut composition in pigs within and across research experiments

2004 ◽  
Vol 55 (9) ◽  
pp. 973 ◽  
Author(s):  
D. Suster ◽  
B. J. Leury ◽  
C. D. Hofmeyr ◽  
D. N. D'Souza ◽  
F. R. Dunshea
Keyword(s):  
Mineral Content ◽  
Dual Energy ◽  
Regression Equations ◽  
Lean Tissue ◽  
Large White ◽  
Tissue Mass ◽  
X Ray ◽  
Fat Composition ◽  
Non Destructive ◽  
Total Tissue

A Hologic QDR4500A dual energy X-ray absorptiometer (DXA) was used to measure body composition in 199 half-carcasses ranging from 15 to 48 kg. Half-carcasses were from animals of mixed sex and of either Large White × Landrace or Large White × Landrace × Duroc descent. Half-carcasses were selected from 5 different experiments to evaluate DXA accuracy within and across experiments. Values determined by DXA including total tissue mass, fat tissue mass, lean tissue mass, and bone mineral content, for the half-carcass and the shoulder, loin, belly, and ham primal cuts were evaluated by comparison with manually dissected composition. Relationships between manually dissected values and measurements of weight and backfat at the P2 site were also evaluated. Manually dissected values were strongly related to DXA-derived values, more so than with weight and P2 or a combination of both, particularly in the measurement of fat composition. In contrast to estimates derived from weight and P2, DXA-derived estimates remained accurate even when between-experiment variation was included. However, because DXA estimates were different from manually dissected values, they would need to be adjusted with the use of appropriate regression equations to correct the in-built algorithms. These results demonstrate the efficacy of DXA as a non-destructive method for determining the composition of the half-carcass and primal cuts, and its greater precision than current routinely used methods.

Accuracy of dual energy X-ray absorptiometry, weight, longissimus lumborum muscle depth and GR fat depth to predict half carcass composition in sheep

2007 ◽  
Vol 47 (10) ◽  
pp. 1165 ◽  
Author(s):  
F. R. Dunshea ◽  
D. Suster ◽  
P. J. Eason ◽  
R. D. Warner ◽  
D. L. Hopkins ◽  
...  
Keyword(s):  
Mineral Content ◽  
Dual Energy ◽  
Carcass Composition ◽  
Regression Equations ◽  
Tissue Mass ◽  
X Ray ◽  
Longissimus Lumborum ◽  
The Relationship ◽  
Non Destructive ◽  
Total Tissue

A Hologic QDR4500W dual energy X-ray absorptiometer (DXA) was used to measure body composition in 60 sheep half carcasses ranging from 8 to 28 kg. Half carcasses were from ewes and wethers of mixed genetics. Values determined by DXA, including total tissue mass (TTM), lean tissue mass (LTM), fat tissue mass (FTM) and bone mineral content (BMC), for the half carcass were evaluated by comparison with chemically determined composition. In the case of BMC, the relationship was with chemically determined ash content. Liveweight and chemically determined lean, fat and ash were strongly related to DXA-derived values for TTM, LTM, FTM and BMC, respectively (R2 = 0.999, 0.986, 0.989 and 0.920, respectively). However, because DXA estimates were different from chemically determined values in this sample of carcasses, they needed to be adjusted with the use of appropriate regression equations to correct the in-built algorithms. These data demonstrate the efficacy of DXA as a non-destructive method for determining the composition of the sheep half carcass.

Repeatability of pig body composition measurements using dual energy X-ray absorptiometry and influence of animal size and subregional analyses

2006 ◽  
Vol 46 (11) ◽  
pp. 1447 ◽  
Author(s):  
D. Suster ◽  
B. J. Leury ◽  
D. J. Kerton ◽  
F. R. Dunshea
Keyword(s):  
Body Composition ◽  
Mineral Content ◽  
Regional Analysis ◽  
Dual Energy ◽  
Whole Body ◽  
Lean Tissue ◽  
Tissue Mass ◽  
X Ray ◽  
Animal Size ◽  
Total Tissue

Fifteen Large White × Landrace male pigs were used to investigate the influence of animal size and subregional analysis technique on dual energy X-ray absorptiometry body composition measurements and their repeatability. Pigs were scanned in triplicate with an Hologic QDR4500A X-ray absorptiometer at the beginning of the study (3 weeks of age, liveweight 5–10 kg) and then every 4 weeks until 19 weeks of age. Measurements made by dual energy X-ray absorptiometry included total tissue mass, lean tissue mass, fat tissue mass and bone mineral content. The QDR4500 software allows the scanned image to be divided into head, arms, legs and trunk using an in-built regional analysis grid that contains algorithms unique to each region. Different regional grid manipulations were performed at each scan to evaluate the effects of incorporating subregions into a whole body analysis over time. The dual energy X-ray absorptiometry measurements were highly repeatable and measurement repeatability improved as animal size increased. When results were averaged across regional grid placement and scan time, the most repeatable measurement was total tissue mass (CV = 0.21%), followed by lean tissue mass (CV = 0.59%), bone mineral content (CV = 2.50%) and fat tissue mass (CV = 2.71%). The placement of the regional analysis grid influenced the repeatability of all measurements except for total weight; however, this influence reduced with increasing animal size. It is recommended that the body of the scan image be positioned in the arm region and the head in the head region of the software regional analysis grid to measure whole body composition in pigs because it provides the most repeatable measure overall. Animal placement into the trunk region or utilising the full regional analysis option as specified by the manufacturer provided less repeatable results.

scholarly journals Relationship between Dual-Energy X-Ray Absorptiometry-Derived Appendicular Lean Tissue Mass and Total Body Skeletal Muscle Mass Estimated by Ultrasound

2013 ◽  
Vol 04 (06) ◽  
pp. 283-286 ◽  
Author(s):  
Takashi Abe ◽  
Nicole C. Dabbs ◽  
Vinayak K. Nahar ◽  
M. Allison Ford ◽  
Martha A. Bass ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Skeletal Muscle Mass ◽  
Dual Energy ◽  
Lean Tissue ◽  
Tissue Mass ◽  
Lean Tissue Mass ◽  
X Ray ◽  
Total Body

scholarly journals Head, Neck, Trunk, and Pelvis Tissue Mass Predictions for Older Adults using Anthropometric Measures and Dual-Energy X-Ray Absorptiometry

2020 ◽  
Vol 8 (3) ◽  
pp. 14
Author(s):  
Charles A.J. Kahelin ◽  
Nicole C. George ◽  
Danielle L. Gyemi ◽  
David M. Andrews
Keyword(s):  
Older Adults ◽  
Dual Energy ◽  
Regression Equations ◽  
Prediction Equations ◽  
Tissue Mass ◽  
Younger Adults ◽  
X Ray ◽  
Recreational Activities ◽  
Biomechanical Models ◽  
Head Neck

Background: Regression equations using anthropometric measurements to predict soft (fat mass [FM], lean mass [LM], wobbling mass [WM]) and rigid (bone mineral content [BMC]) tissue masses of the extremities and core body segments have been developed for younger adults (16-35 years), but not older adults (36-65 years). Tissue mass estimates such as these would facilitate biomechanical modeling and analyses of older adults following fall or collision-related impacts that might occur during sport and recreational activities. Purpose: The purpose of this study was to expand on the previously established tissue mass prediction equations of the head, neck, trunk, and pelvis for healthy, younger adults by generating a comparable set of equations for an older adult population. Methods: A generation sample (38 males, 38 females) was used to create head, neck, trunk, and pelvis tissue mass prediction equations via multiple linear stepwise regression. A validation sample (13 males, 12 females) was used to assess equation accuracy; actual tissue masses were acquired from manually segmented full body Dual-Energy X-ray Absorptiometry scans. Results: Adjusted R2 values for the prediction equations ranged from 0.326 to 0.949, where BMC equations showed the lowest explained variances overall. Mean relative errors between actual and predicted masses ranged from –2.6% to 6.1% for trunk LM and FM, respectively. All actual tissue masses except head BMC (R2 = 0.092) were significantly correlated to those predicted from the equations (R2 = 0.403 to 0.963). Conclusion: This research provides a simple and effective method for predicting head, neck, trunk, and pelvis tissue masses in older adults that can be incorporated into biomechanical models for analyzing sport and recreational activities. Future work with this population should aim to improve core segment BMC predictions and develop equations for the extremities.

scholarly journals Conjugated linoleic acid decreases fat accretion in pigs: evaluation by dual-energy X-ray absorptiometry

2003 ◽  
Vol 89 (2) ◽  
pp. 219-229 ◽  
Author(s):  
Ewa Ostrowska ◽  
Danny Suster ◽  
Morley Muralitharan ◽  
Reg F. Cross ◽  
Brian J. Leury ◽  
...  
Keyword(s):  
Bone Mineral ◽  
Dual Energy ◽  
Average Weight ◽  
Regression Equations ◽  
Dependent Manner ◽  
Mineral Density ◽  
Large White ◽  
X Ray ◽  
Predicted Values ◽  
Dietary Treatments

Thirty female Large White × Landrace pigs (average weight 57·2 (SD 1·9) kg) were allocated to one of six dietary treatments containing 0, 1·25, 2·5, 5·0, 7·5 or 10·0 g 55 % conjugated linoleic acids (CLA) isomers (CLA-55)/kg diet and fed for 8 weeks. Each pig was scanned at 0, 28 and 56 d and again at post slaughter using dual-energy X-ray absorptiometry (DXA) to determine the temporal pattern of body composition responses. Values determined by DXA were adjusted using regression equations generated from validation experiments between chemically and DXA-predicted values. Overall, there was a significant linear reduction in fat content with the increasing levels of CLA in the diet (P=0·007,P=0·011,P=0·008 at week 4, week 8 and for the carcass, respectively). The greatest improvement was recorded at the early stages of CLA supplementation and for the highest dose of CLA (week 4, −19·2 % compared with week 8, −13·7 %). In the first 4 weeks of feeding CLA, pigs receiving 10 g CLA-55/kg diet deposited 93 g less fat/d than pigs fed basal diets (P=0·002) compared with only 6 g less fat than control animals in the final 4 weeks. Lean content and lean deposition rate were maximised at 5 and 2·5 g CLA-55/kg diet for the first 4 weeks (P=0·016) and the final 4 weeks of treatment (P=0·17), respectively. DXA estimates of bone mineral content and bone mineral density were not affected by CLA supplementation throughout the experiment. These data demonstrate that dietary CLA decreases body fat in a dose-dependent manner and that the response is greatest over the initial 4 weeks of treatment.

Porcine somatotropin alters body composition and the distribution of fat and lean tissue in the finisher gilt

2005 ◽  
Vol 45 (6) ◽  
pp. 683 ◽  
Author(s):  
D. Suster ◽  
B. J. Leury ◽  
R. Hewitt ◽  
D. J. Kerton ◽  
F. R. Dunshea
Keyword(s):  
Feed Intake ◽  
Dual Energy ◽  
Feed Conversion ◽  
Lean Tissue ◽  
Large White ◽  
X Ray ◽  
Porcine Somatotropin ◽  
Available Lysine ◽  
Dose Dependent Decrease ◽  
Dose Dependent

The present study was designed to determine whether porcine somatotropin (pST) reduces whole animal and belly fat using dual energy X-ray absorptiometry and manual dissection. The study utilised 24 Large White × Landrace gilts selected at 16 weeks of age with an approximate liveweight of 80 kg and housed in individual pens. Gilts were stratified on liveweight into 8 blocks and 1 pig from each block was assigned to either 0, 5 or 10 mg per day of pST. Pigs were fed ad libitum a wheat-based diet containing 200 g crude protein, 10.2 g available lysine and 14.6 MJ DE/kg, to ensure that responses to pST were expressed. Feed intake and liveweight were measured on a weekly basis. An Hologic QDR4500A dual energy X-ray absorptiometer was used to determine lean, fat and ash composition of pigs initially and again 4 weeks later at the end of the experiment. After slaughter, the composition of the whole half carcass as well as the shoulder, ham, belly and loin primal cuts was determined with dual energy X-ray absorptiometry and verified with manual dissection. Daily pST treatment decreased feed intake (3440, 2710 and 2537 g/day for 0, 5 or 10 mg pST per day, respectively; P<0.001) and decreased feed conversion ratio (2.95, 2.18 and 2.03 g/g; P<0.001) even though there was no significant effect on daily gain. Pigs treated with pST deposited more lean tissue (620, 839 and 873 g/day; P<0.05) and less fat (384, 218 and 176 g/day; P<0.001) than control animals, but there was no effect of pST on ash deposition. As a consequence, pigs treated with 5 and 10 mg pST/day contained 5 and 9 kg less dissectible fat than control gilts, respectively. A dose dependent decrease in belly, loin, ham and shoulder fat was also observed, although the decrease in belly fat was more pronounced than for the whole carcass and other primal cuts. Overall, pST treatment has the potential to decrease carcass and especially belly fat in pigs and increase consumer acceptance of pork in markets that place a premium on carcass fat and lean yield in the belly region. The results determined with dual energy X-ray absorptiometry were confirmed by manual dissection.

Head, Neck, Trunk, and Pelvis Tissue Mass Predictions for Young Adults Using Anthropometric Measures and Dual-Energy X-Ray Absorptiometry

2017 ◽  
Vol 33 (5) ◽  
pp. 366-372
Author(s):  
Danielle L. Gyemi ◽  
Charles Kahelin ◽  
Nicole C. George ◽  
David M. Andrews
Keyword(s):  
Young Adults ◽  
Head And Neck ◽  
Dual Energy ◽  
Regression Equations ◽  
Prediction Equations ◽  
Anthropometric Measures ◽  
Tissue Mass ◽  
X Ray ◽  
Head Neck

Accurate prediction of wobbling mass (WM), fat mass (FM), lean mass (LM), and bone mineral content (BMC) of living people using regression equations developed from anthropometric measures (lengths, circumferences, breadths, skinfolds) has previously been reported, but only for the extremities. Multiple linear stepwise regression was used to generate comparable equations for the head, neck, trunk, and pelvis of young adults (38 males, 38 females). Equations were validated using actual tissue masses from an independent sample of 13 males and 13 females by manually segmenting full-body dual-energy x-ray absorptiometry scans. Prediction equations exhibited adjusted R2 values ranging from .249 to .940, with more explained variance for LM and WM than BMC and FM, especially for the head and neck. Mean relative errors between predicted and actual tissue masses ranged from −11.07% (trunk FM) to 7.61% (neck FM). Actual and predicted tissue masses from all equations were significantly correlated (R2  = .329 to .937), except head BMC (R2  = .046). These results show promise for obtaining in-vivo head, neck, trunk, and pelvis tissue mass estimates in young adults. Further research is needed to improve head and neck FM and BMC predictions and develop tissue mass prediction equations for older populations.

Validation of Estimates of Lean Tissue Mass Made by Dual-Energy X-ray Absorptiometry

2006 ◽  
Vol 904 (1) ◽  
pp. 104-106 ◽  
Author(s):  
IAN R. J. HUMPHRIES ◽  
V. HUA ◽  
L. BAN ◽  
K. J. GASKIN ◽  
R. HOWMAN-GILES
Keyword(s):  
Dual Energy ◽  
Lean Tissue ◽  
Tissue Mass ◽  
Lean Tissue Mass ◽  
X Ray
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