Lean Fat-free Mass Research Articles

28 Investigation of protein deposition pattern of PIC337×Camborough commercial pigs

Abstract The objective of the trial was to investigate the protein deposition pattern of PIC337×Camborough commercial pigs. A total of 1,064 barrows and gilts [PIC337×Camborough, initial body weight (BW) = 6.0 ± 0.1 kg] were used in the trial with 38 mixed sex pens, 28 pigs per pen. At the beginning of the trial, the lightest 10% of the barrows and gilts were selected and placed in four pens (equal numbers of barrows and gilts within a pen), and the remaining pigs were randomly placed into the other pens (equal numbers of barrows and gilts within a pen). A common 6-phase corn-soybean based wean-to-finish diets were fed throughout the trial. Dietary net energy and standardized ileal digestible lysine levels were (6-10 kg BW: 2,600 Kcal/kg and 1.35%; 10-20 kg BW: 2,520 Kcal/kg and 1.30%; 20-38 kg BW: 2,470 Kcal/kg and 1.20%; 38-72 kg BW: 2,450 Kcal/kg and 0.98%; 72-127 kg BW: 2,450 Kcal/kg and 0.87%; and 127-149 kg BW: 2,450 Kcal/kg and 0.77%). On d 97 after placement, 5 barrows and 5 gilts with BW close to pen average were selected for individual BW by a portable scale and 10th rib backfat and loin depth measurements (ExaGo portable ultrasound scanner, Imv imaging, UK). Then on d 111, 117, 136, 142, and 167 after placement, the same 5 barrows and 5 gilts were measured for individual BW, 10th rib backfat and loin depth. The fat-free lean mass is estimated by the equation 6.783-0.6198×(10th rib backfat depth, mm)+0.1578×(10th rib loin depth, mm)+1.0362×(warm carcass weight, kg). A constant carcass yield of 75% was used to estimate warm carcass weight. Data were analyzed using a linear mixed model in R Studio (Version 3.5.2, R Core Team; Vienna, Austria). The average BW of pigs at the 6 measurements were: 77.2, 92.4, 99.2, 122.5, 128.0, and 153.6 kg, respectively. The average daily gain (ADG) was 1,139, 1,155, 1,145, 1,126, and 977 g/d for 77.2 to 92.4 kg BW, 92.4 to 99.2 kg BW, 99.2 to 122.5 kg BW, 122.5 to 128.0 kg BW, and 128.0 to 153.6 kg BW, respectively. The average daily 10th rib backfat depth gain was 0.05, 0.08, 0.15, 0.17, and 0.20 mm/d. The average daily 10th rib loin depth gain was 0.42, 0.43, 0.41, 0.39, and 0.23 mm/d. The average daily fat-free lean mass gain (ADFFLG) was 547, 551, 528, 515, and 422 g/d. The fitted quadratic model for ADG is 83.57782 + 19.90632 × (BW, kg)-0.09176×(BW, kg)2, and the calculated maximum ADG was 1,163 g/d when BW was 108.5 kg. The fitted quadratic model for ADFFLG is 85.90926 + 9.23773 × (BW, kg) - 0.04591 × (BW, kg)2, and the calculated maximum ADFFLG is 550.6 g/d when BW was 100.6 kg. Under the conditions of the current trial, PIC337×Camborough pigs reaches the maximum rate of protein deposition at BW between 100.6 and 108.5 kg.

PSIII-A-8 Daily Clenbuterol Administration to Lambs Born with low Birthweight due to Intrauterine Growth Restriction Recovered Growth Rates and Improved Body Composition at 60 D of age

Abstract Low birthweight due to intrauterine growth restriction (IUGR) results from unfavorable in utero conditions (i.e., hypoxemia, hypoglycemia) that impairs growth capacity for muscle and other tissues. This programming effect reduces growth efficiency in IUGR offspring below their genetic potential. Specific programming mechanisms are not known, but recent evidence indicates reduced β2 adrenergic regulation of IUGR muscle. Thus, our objective was to determine if early-life growth deficits in IUGR juvenile lambs are improved by manipulating β2 adrenergic activity with daily IM administration of the β2 agonist, clenbuterol (Clen), from birth to 60 d of age. Maternal heat stress-induced IUGR (n=10) and IUGR+Clen (n=9) lambs were smaller (P< 0.05) than controls (n=11) at birth, weighed 18% and 11% less (P< 0.05), respectively, than controls at 30 d of age, and weighed 16% and 13% less (P< 0.05), respectively, at 60 d of age. Average daily gain at 30 and 60 d of age was reduced (P≤0.05) for IUGR but not IUGR+Clen lambs compared to controls. Bioelectrical impedance analysis was used to estimate body composition in live lambs at 58 d of age. Estimated fat-free lean mass and estimated muscle mass were less (P≤0.05) for IUGR but not IUGR+Clen lambs compared to controls. Estimated protein and fat content as well as protein:fat were likewise reduced (P< 0.05) for IUGR but not IUGR+Clen lambs. At necropsy, whole hindlimbs tended to be lighter (P≤0.09) and flexor digitorum superficialis muscle was lighter (P< 0.05) for IUGR but not IUGR+Clen lambs compared to controls. Loin-eye areas measured in chilled carcasses were 15% smaller (P< 0.05) for IUGR lambs and 19% larger (P< 0.05) for IUGR+Clen lambs compared to controls. From this study, we conclude that poor postnatal growth and body composition observed in IUGR juvenile lambs was improved when clenbuterol was used to target programmed deficits in β2 adrenergic regulation of muscle.

1441-P: Fidelity of BMI and Waist Circumference as Adiposity Measures in White and Black Adults

Background: Body mass index (BMI) and waist circumference (WC) are routine clinical estimates of obesity. We tested the fidelity of BMI and WC against direct body fat measures in Black (B) vs. White (W) Americans. Subjects and Methods: We analyzed the relationship between BMI vs. total fat, WC vs. trunk fat, and weight vs. lean fat free mass (FFM) in healthy B and W adults. Assessments included clinical exam, biochemistries and a 75-g OGTT. All subjects had normal fasting and 2-hr OGTT glucose levels. Total fat mass, trunk fat mass and FFM were measured using DXA. Results: The participants (n=376; 217 B, 159 W) had an age range of 18-65 years and BMI range of 16.8-66.3 kg/m2 (mean 30.1) . The W vs. B values were: age 46.5 ± 10.5 vs. 42.5 ± 10.3 y, P=0.0003; BMI 28.8 ± 6.78 vs. 31.2 ± 7.40, P=0.0015; total fat mass 29.4 ± 13.21 vs. 31.8 ± 13.76 kg, P=0.11; trunk fat mass 14.77 ± 6.96 vs. 15.34 ± 7.50 kg, P=0.48; FFM 50.12 ± 11.9 vs. 53.± 11.74 kg, P= 0.03. There were tight correlations between adiposity measures: total fat and BMI (r=0.90 in W, 0.92 in B) ; trunk fat and WC (r=0.85 in W, 0.82 in B) ; FFM and weight (r=0.83 in W, 0.87 in B) , with heterogeneity by sex and race. White men and women (vs B) tended to have more body fat per unit BMI or WC and less FFM per unit weight. We assessed 3 integrated ratios (total Fat/BMI, trunk Fat/Waist, FFM/Weight) by sex and race. Total fat/BMI was higher (P<0.0001) in W vs. B (men: 0.946 ± 0.159 vs. 0.833 ± 0.210; women: 1.36 ± 0.189 vs. 1.25 ± 0.164) . Trunk fat/waist was higher in W vs. B men (0.294 + 0.043 in W vs. 0.257 + 0.072, P=0.0046) but similar in women. In contrast, FFM/weight ratio showed no race disparities (men: 0.696 ± 0.055 vs. 0.678 ± 0.200; women: 0.586 ± 0.1vs 0.579 ± 0.076) . The proportion with >3 metabolic syndrome markers was 24.5% in W and 15.7% in B. Conclusion: Among otherwise healthy subjects with a wide BMI range, African Americans had lower body fat than Whites. This finding that argues for ethnic-specific BMI cut-offs for obesity classification. Disclosure Z.Liu: None. A.A.Patel: None. S.Dagogo-jack: Consultant; AstraZeneca, Bayer AG, Boehringer Ingelheim International GmbH, Janssen Pharmaceuticals, Inc., Medtronic, Merck & Co., Inc., Sanofi. Funding American Diabetes Association (7-07-MN-13) ; NIH, R01 DK067269

Correlation Between Body Composition Analysis and Biochemical Nutritional Markers in Maintenance Hemodialysis Patients with Chronic Liver Disease

Several approaches have been used to assess protein-energy wasting syndrome, such as clinical evaluation, biochemical nutritional markers, anthropometric measurements, but Bioelectrical Impedance Analysis (BIA) techniques hold a central place in clinical settings. The aim of this study is to report our clinical experience with BIA and the correlations between biochemical nutritional markers and BIA nutritional parameters in hemodialysis (HD) patients associating or free of chronic liver disease. This cross-sectional observational study included 69 HD patients divided into two groups: 33 with chronic liver disease (CLD+) versus 36 chronic liver disease-free (CLD-) from one HD unit in Romania. Serum albumin (SA), serum creatinine (SCr) and C-reactive protein (CRP) were obtained from the HD arterial line immediately before the HD session and by BIA the body composition including total body water (TBW), total body fat (TBF), lean fat free mass(LFFM), body muscular mass (BMM), malnutrition index and body protein reserve (PR) were assessed. No significant differences between groups were found in BCM, BMM, PR and TBF (p = 0.92, p = 0.60, p = 0.907, and p = 0.634, respectively). Malnutrition index had a significantly higher mean value in HD-CLD(+) patients (p = 0.00). HD-CLD(-) group showed a strong correlation between SA and SCr and BCM, BMM (kg), LFFM (kg) and body PR (kg) (r=.48, r=.50, r=.44, r=.50; resp. r=.42, r=.40, r=.36, r=.42). In HD-CLD(+) patients, a significant positive correlation was found between SA and SCr and LFFM and body PR (r=.37, r=.35; resp. r=.44, r=.35). Discussion: BIA is one of the most accurate techniques for assessing nutritional status and should be regularly used in clinical practice along with biochemical nutritional markers in HD patients. Although the protein metabolism depends to a large extent on liver function, CLD cannot be considered as having a significant impact on nutritional status in HD patients.

Lean Mass and Body Fat Percentage Are Contradictory Predictors of Bone Mineral Density in Pre-Menopausal Pacific Island Women.

Anecdotally, it is suggested that Pacific Island women have good bone mineral density (BMD) compared to other ethnicities; however, little evidence for this or for associated factors exists. This study aimed to explore associations between predictors of bone mineral density (BMD, g/cm2), in pre-menopausal Pacific Island women. Healthy pre-menopausal Pacific Island women (age 16–45 years) were recruited as part of the larger EXPLORE Study. Total body BMD and body composition were assessed using Dual X-ray Absorptiometry and air-displacement plethysmography (n = 83). A food frequency questionnaire (n = 56) and current bone-specific physical activity questionnaire (n = 59) were completed. Variables expected to be associated with BMD were applied to a hierarchical multiple regression analysis. Due to missing data, physical activity and dietary intake factors were considered only in simple correlations. Mean BMD was 1.1 ± 0.08 g/cm2. Bone-free, fat-free lean mass (LMO, 52.4 ± 6.9 kg) and age were positively associated with BMD, and percent body fat (38.4 ± 7.6) was inversely associated with BMD, explaining 37.7% of total variance. Lean mass was the strongest predictor of BMD, while many established contributors to bone health (calcium, physical activity, protein, and vitamin C) were not associated with BMD in this population, partly due to difficulty retrieving dietary data. This highlights the importance of physical activity and protein intake during any weight loss interventions to in order to minimise the loss of muscle mass, whilst maximizing loss of adipose tissue.

The aging myostatin null phenotype: reduced adiposity, cardiac hypertrophy, enhanced cardiac stress response, and sexual dimorphism

The natural aging process results in the physiological decline of multiple tissues and organ systems. Changes commonly occur with middle age and include decreased skeletal muscle mass, bone mineral density, cardiac output, and insulin sensitivity, and increased adiposity, all of which can contribute to the onset of sarcopenia, osteoporosis, heart failure, or type 2 diabetes. Recent studies suggest that myostatin may influence many of these systems. We therefore sought to determine whether they are affected by aging, especially in 'middle-aged' Mstn-/- mice (12-20 months old (m.o.)). Although body weights were similar in wild-type (WT) and Mstn-/- mice, lean fat-free mass and skeletal muscles composed of predominantly type I, II, and mixed fibers were significantly heavier in Mstn-/- mice. These differences were accompanied by lower total adiposity, especially in female mice, white and brown fat pad weights, and adipocyte size. Hearts were heavier in Mstn-/- mice across a large age range (3-24 m.o.) and exhibited signs of dilated cardiomyopathy at rest, which include lower strain measurements compared with WT myocardium. However, Mstn-/- mice responded better to isoproterenol stress tests with greater increases in fractional shortening and ejection fraction-differences that were again more apparent in females and which are consistent with physiological cardiac hypertrophy. Spleens and kidneys were also smaller, although histologically normal, in Mstn-/- mice. These data together suggest that attenuating myostatin could potentially prevent or possibly treat pathological conditions that develop with age. Additional studies are nevertheless needed to definitively assess potential risks to cardiac function.

The impact of feeding diets of high or low energy concentration on carcass measurements and the weight of primal and subprimal lean cuts.

Pigs from four sire lines were allocated to a series of low energy (LE, 3.15 to 3.21 Mcal ME/kg) corn-soybean meal-based diets with 16% wheat midds or high energy diets (HE, 3.41 to 3.45 Mcal ME/kg) with 4.5 to 4.95% choice white grease. All diets contained 6% DDGS. The HE and LE diets of each of the four phases were formulated to have equal lysine:Mcal ME ratios. Barrows (N = 2,178) and gilts (N = 2,274) were fed either high energy (HE) or low energy (LE) diets from 27 kg BW to target BWs of 118, 127, 131.5 and 140.6 kg. Carcass primal and subprimal cut weights were collected. The cut weights and carcass measurements were fitted to allometric functions (Y = A CWB) of carcass weight. The significance of diet, sex or sire line with A and B was evaluated by linearizing the equations by log to log transformation. The effect of diet on A and B did not interact with sex or sire line. Thus, the final model was B) where Diet = −0.5 for the LE and 0.5 for HE diets and A and B are sire line-sex specific parameters. cut weight = (1+bD(Diet)) A(CW Diet had no affect on loin, Boston butt, picnic, baby back rib, or sparerib weights (p>0.10, bD = −0.003, −0.0029, 0.0002, 0.0047, −0.0025, respectively). Diet affected ham weight (bD = −0.0046, p = 0.01), belly weight (bD = 0.0188, p = 0.001) three-muscle ham weight (bD = −0.014, p = 0.001), boneless loin weight (bD = −0.010, p = 0.001), tenderloin weight (bD = −0.023, p = 0.001), sirloin weight (bD = −0.009, p = 0.034), and fat-free lean mass (bD = −0.0145, p = 0.001). Overall, feeding the LE diets had little impact on primal cut weight except to decrease belly weight. Feeding LE diets increased the weight of lean trimmed cuts by 1 to 2 percent at the same carcass weight.

Efeito da fisioterapia contra-resistida com relação à massa corporal magra em pacientes no pós-operatório de cirurgia bariátrica

RACIONAL: Cálculos metabólicos e de atividade física são realizados a partir do tecido ativo presente no corpo, conhecido como massa corporal magra, que resulta da soma da massa magra isenta de gordura com a gordura essencial. A cinesioterapia é a musculação terapêutica que auxilia na força e flexibilidade. OBJETIVOS: No paciente submetido a tratamento cirúrgico para obesidade mórbida: 1) avaliar o efeito da fisioterapia contra-resistida na massa magra; 2) avaliar os fatores associados às variações de massa corporal magra com tratamento fisioterapêutico; 3) comparar o grupo de pacientes que perdeu com o que ganhou massa magra com o tratamento fisioterapêutico, analisando as co-morbidades que interferiram para esses resultados. MÉTODO: Foram incluídos 100 pacientes operados pela técnica de Fobi-Capella, ou derivação em Y-de-Roux, sem anel e divididos em grupo A composto por pacientes que perderam massa corporal magra nos dois períodos avaliados (entre 30 dias e três meses e entre três meses e seis meses) e o grupo B pelos demais pacientes que apresentaram ganho de massa corporal magra em pelo menos um dos períodos avaliados. A coleta de dados foi realizada através do Protocolo Eletrônico Multiprofissional em Cirurgia Bariátrica e Metabólica com Ênfase em Fisioterapia, identificado pela siga SINPE© (Sistema Integrado de Protocolos Eletrônicos). Os pacientes realizaram avaliação fisioterapêutica pré-operatória e foram acompanhados no período pós-operatório em quatro fases: na internação hospitalar, submetidos à musculação terapêutica em 30 dias após a operação, aos três meses e aos seis meses do pós-operatório. RESULTADOS: Houve diferença significativa entre as três avaliações (p<0,001). Ao comparar a de 30 dias com três meses, foi observada perda de massa corporal magra com significância estatística (p<0,001). Da mesma forma, entre 30 dias e seis meses (p<0,001). Entretanto, o período entre três meses e seis meses não apresentou resultado com significância (p<0,612), demonstrando tendência à manutenção de massa corporal magra. CONCLUSÕES: A fisioterapia contra-resistida auxiliou na manutenção da massa corporal magra entre os períodos de três meses e seis meses; 2) homens idosos, diabéticos e dislipidêmicos perderam mais massa magra, sendo que o tempo de obesidade, doenças cardiovasculares e ortopédicas não interferiram nas variações de massa magra; 3) os grupos A e B não apresentaram diferenças significativas tanto para ganho como para perda em relação às doenças cardiovasculares e ortopédicas; porém, pacientes com diabete melito e dislipidemias encontravam-se mais no Grupo A.

Relationships among dual-energy X-ray absorptiometry, bioelectrical impedance and ultrasound measurements of body composition of swine

Abstract. In three separate studies (156 pigs total), dual-energy X-ray absorptiometry (DXA), bioelectrical impedance (BIA) and ultrasound were compared as methods for measuring live body composition of pigs at 60 and 100-110 kg BWt. DXA measured total body fat and lean content, BIA measurements of resistance (Rs) and reactance (Xc) were used to calculate total body lean mass and ultrasound measurements of backfat (BF) depth and longissimus muscle area (LMA) were used to calculate total carcass lean mass. Following the 100–110 kg measurements, the pigs were slaughtered and the half-carcass analyzed chemically for fat and water content. At 110 kg both DXA and ultrasound measurements were significantly correlated with the percentages of carcass fat and water, although correlations were higher for DXA. The correlations between DXA and BF measurements were higher at 110 kg than at 60 kg, whereas they were lower for DXA and LMA. For pigs measured at 100 kg there were high correlations between the DXA values and the BIA estimates for both percentage of fat-free lean mass (FFM %) and FFM kg. Furthermore, the correlations between the BIA estimates of FFM and carcass fat and water content were similar to those for DXA and the same carcass values. This study also provided a side-by-side comparison of the BIA and ultrasound lean measurements relative to DXA and carcass composition. The BIA lean measurement correlated more highly with both DXA and carcass composition than did the ultrasound lean measurement.

Building muscle: nutrition to maximize bulk and strength adaptations to resistance exercise training

Several nutritional strategies can optimize muscle bulk and strength adaptations and enhance recovery from heavy training sessions. Adequate energy intake to meet the needs of training and carbohydrate intake sufficient to maintain glycogen stores (>7 g carbohydrate·kg−1·day−1 for women; >8 g carbohydrate·kg−1·day−1 for men) are important. Dietary protein intake for top sport athletes should include some foods with high biological value, with a maximum requirement of approximately 1.7 g·kg−1·day−1 being easily met with an energy sufficient diet. The early provision of carbohydrate (>1 g·kg−1) and protein (>10 g) early after an exercise session will enhance protein balance and optimize glycogen repletion. Creatine monohydrate supplementation over several days increases body mass through water retention and can increase high-intensity repetitive ergometer performance. Creatine supplementation can enhance total body and lean fat free mass gains during resistance exercise training; however, strength gains do not appear to be enhanced versus an optimal nutritional strategy (immediate post-exercise protein and carbohydrate). Some studies have suggested that β-OH-methyl butyric acid (β-HMB) can enhance gains made through resistance exercise training; however, it has not been compared “head to head” with optimal nutritional practices. Overall, the most effective way to increase strength and bulk is to perform sport-specific resistance exercise training with the provision of adequate energy, carbohydrate, and protein. Creatine monohydrate and β-HMB supplementation may enhance the strength gains made through training by a small margin but the trade-off is likely to be greater bulk, which may be ergolytic for any athlete participating in a weight-supported activity.

Evaluation of the impact of errors in the measurement of backfat depth on the prediction of fat-free lean mass

The development of regression equations to predict carcass composition typically assumes that the independent variables, such as backfat depth, are measured without error. However, technological and operator-specific types of measurement errors do exist. To evaluate the impact of measurement error for backfat depth, Monte Carlo simulation was used to model carcass fat-free lean mass (FFLM) in pigs. In the simulation, FFLM was a linear function of carcass weight and actual backfat depth (ABFD). Carcass weight was assumed to be measured without error, but measurement errors were generated such that the correlation (r(BF)) of the measured backfat depth (BFD) and ABFD ranged from 0.70 to 0.95. Two types of measurement errors were simulated: 1) constant variation that was additive to the variance of ABFD, and 2) variation proportional to the ABFD that was additive to the variance in ABFD. A total of 1,000 replications of 1,000 pigs were simulated. Within each type of measurement error, the absolute values of the regression coefficients and R2 values of the equations decreased as r(BF) decreased. The probability of the backfat depth squared (BFD2) being significant (P < 0.05) in the regression equation was increased when the measurement errors were proportional to ABFD. The occurrence of a significant BFD2 variable was 792 times out of 1,000 replications when r(BF) = 0.95 and increased to 996 times out of 1,000 when r(BF) = 0.85 for BFD with type 2 measurement errors. The inclusion of a CW x BFD variable in the regression equations (P < 0.05) increased (270 to 423 times out of 1,000) as r(BF) decreased from 0.85 to 0.70 for BFD with type 2 errors. Equations developed from BFD with measurement errors resulted in biased predictions of FFLM and changes in FFLM per unit change in BFD. The level and type of measurement errors that exist in the independent variables should be evaluated.

Evaluation of Alternative Methods to Develop Prediction Equations to Predict Carcass Fat-Free Lean Mass

Carcass measurements of 203 pigs representing 7 genetic populations and 4 target weights (100, 114, 128, and 152 kg) were used to evaluate alternative equations to predict carcass fat tissue-free lean mass. Independent variables in the equations included carcass weight and measures of backfat depth and longissimus area. Alternative sets of equations were calculated to evaluate the inclusion of a random effect of week of processing and of the quadratic and cross-product independent variables. In addition, equations were developed from data including the overall data set as well as from the 3 lightest and 3 heaviest target weights. Overall, the addition of the random effect of week did not change the residual standard deviations of the prediction equations. For 4 equations, the inclusion of the random effect of week reduced the absolute value of the regression coefficients. The best equations developed from either the light or heavy pig data sets had less total residual sums of squares and less residual sums of squares accounted for by target BW group than did the best equations developed from the overall data set. In 2 of the 4 cases, the best linear equation developed from the light or heavy data sets had less residual sums of squares than the best equation based on the overall data set.

BMD and Body Composition in Children and Young Patients Affected by Cystic Fibrosis

Abstract Longer survival in cystic fibrosis has led to more bone complications. One hundred thirty-six young patients were studied for 12-24 months. Low BMD was found in 66%. Fat mass and lean mass were also reduced. Impaired pulmonary function and total steroid dose had the greatest negative influence on bone. Introduction: Low BMD is reported as a frequent complication in adult patients affected by cystic fibrosis (CF), but the available data are less consistent for younger patients. Materials and Methods: This study was designed to evaluate BMD longitudinally over 12-24 months in a sample of 136 young patients (3-24 years of age) and to investigate its major determinants. BMC and body composition were also evaluated. Results: BMD (expressed as Z score) of spine and of total body was reduced in 66% of patients. The prevalence of low BMD was the same in children, adolescents, and young adults. The main determinants of BMD were forced expiratory volume in 1 s (FEV1; as an index of pulmonary function), puberty, platelet count (as an index of portal hypertension), and cumulative steroid dose. Changes of FEV1 over time influenced BMD changes. Bone mass, fat mass (FM) and fat-free (lean) mass (FFM) were reduced in CF patients at both total body and subregions (trunk, limbs). Lean mass influenced BMD of total body and lower limbs, whereas fat mass (and BMI) influenced spine BMD. FEV1 also influenced FFM. Conclusions: Low BMD was present in a significant proportion of CF patients, independent of sex and age. BMD depended on pulmonary function, steroid dose, and presence of advanced liver disease. Pulmonary function and puberty were the main stimuli for the increase of BMD over time. CF also altered body composition, and FFM was influenced by pulmonary function.

Teriparatide [Human PTH(1-34)]: 2.5 Years of Experience on the Use and Safety of the Drug for the Treatment of Osteoporosis

Longer survival in cystic fibrosis has led to more bone complications. One hundred thirty-six young patients were studied for 12-24 months. Low BMD was found in 66%. Fat mass and lean mass were also reduced. Impaired pulmonary function and total steroid dose had the greatest negative influence on bone.Low BMD is reported as a frequent complication in adult patients affected by cystic fibrosis (CF), but the available data are less consistent for younger patients.This study was designed to evaluate BMD longitudinally over 12-24 months in a sample of 136 young patients (3-24 years of age) and to investigate its major determinants. BMC and body composition were also evaluated.BMD (expressed as Z score) of spine and of total body was reduced in 66% of patients. The prevalence of low BMD was the same in children, adolescents, and young adults. The main determinants of BMD were forced expiratory volume in 1 s (FEV1; as an index of pulmonary function), puberty, platelet count (as an index of portal hypertension), and cumulative steroid dose. Changes of FEV1 over time influenced BMD changes. Bone mass, fat mass (FM) and fat-free (lean) mass (FFM) were reduced in CF patients at both total body and subregions (trunk, limbs). Lean mass influenced BMD of total body and lower limbs, whereas fat mass (and BMI) influenced spine BMD. FEV1 also influenced FFM.Low BMD was present in a significant proportion of CF patients, independent of sex and age. BMD depended on pulmonary function, steroid dose, and presence of advanced liver disease. Pulmonary function and puberty were the main stimuli for the increase of BMD over time. CF also altered body composition, and FFM was influenced by pulmonary function.

Ractopamine treatment biases in the prediction of pork carcass composition.

Carcass and live measurements of 45 barrows were used to evaluate the magnitude of ractopamine (RAC) treatment prediction biases for measures of carcass composition. Barrows (body weight = 69.6 kg) were allotted by weight to three dietary treatments and fed to an average body weight of 114 kg. Treatments were: 1) 16% crude protein, 0.82% lysine control diet (CON); 2) control diet + 20 ppm RAC (RAC16); 3) a phase feeding sequence with 20 ppm RAC (RAC-P) consisting of 18% crude protein (1.08% lysine) during wk 1 and 4, 20% crude protein (1.22% lysine) during wk 2 and 3, 16% crude protein (0.94% lysine) during wk 6, and 16% crude protein (0.82% lysine) during wk 6. The four lean cuts from the right side of the carcasses (n = 15/treatment) were dissected into lean and fat tissue. The other cut soft tissue was collected from the jowl, ribs, and belly. Proximate analyses were completed on these three tissue pools and a sample of fat tissue from the other cut soft tissue. Prediction equations were developed for each of five measures of carcass composition: fat-free lean, lipid-free soft tissue, dissected lean in the four lean cuts, total carcass fat tissue, and soft-tissue lipid mass. Ractopamine treatment biases were found for equations in which midline backfat, ribbed carcass, and live ultrasonic measures were used as single technology sets of measurements. Prediction equations from live or carcass measurements underpredicted the lean mass of the RAC-P pigs and underpredicted the lean mass of the CON pigs. Only 20 to 50% of the true difference in fat-free lean mass or lipid-free soft-tissue mass between the control pigs and pigs fed RAC was predicted from equations including standard carcass measurements. The soft-tissue lipid and total carcass fat mass of RAC-P pigs was overpredicted from the carcass and live ultrasound measurements. Prediction equations including standard carcass measurements with dissected ham lean alone or with dissected loin lean reduced the residual standard deviation and magnitude of biases for the three measures of carcass leanmass. Prediction equations including the percentage of lipid of the other cut soft tissue improved residual standard deviation and reduced the magnitude of biases for total carcass fat mass and soft-tissue lipid. Prediction equations for easily obtained carcass or live ultrasound measures will only partially predict the true effect of RAC to increase carcass leanness. Accurate prediction of the carcass composition of RAC-fed pigs requires some partial dissection, chemical analysis, or alternative technologies.

Evaluation of alternative measures of pork carcass composition.

Carcass and live measurements of 203 pigs representing seven genetic populations and four target live weights (100, 114, 128, and 152 kg) were used to evaluate alternative measures of carcass composition. Measures of carcass lean (fat tissue-free lean, FFLM; lipid-free soft tissue, LFSTIS; and dissected lean in the four lean cuts, DL), fat (total carcass fat tissue, TOFAT), and lipid mass (soft tissue lipid, STLIP) were evaluated. Overall, LFSTIS was 22.8% greater than FFLM (47.8 vs 38.9 kg) and TOFAT was 30% greater than STLIP (38.5 vs 29.6 kg). The allometric growth coefficients relative to carcass weight were different for the measures: b = 0.776, 0.828, 0.794, 1.37, and 1.49 for FFLM, LFSTIS, DL, TOFAT, and STLIP, respectively. At 90 kg carcass weight, the predicted growth of FFLM, LFSTIS, TOFAT, and STLIP was 0.314, 0.420, 0.553, and 0.446 kg/kg increase in carcass weight. The difference between FFLM and LFSTIS, representing nonlipid components of the carcass fat tissue, was greater for barrows than for gilts (9.2 vs 8.6 kg). Lipid-free soft tissue mass was predicted more accurately from carcass or live animal measurements than FFLM with smaller relative RSD (4.6 vs 6.5% of their mean values). The alternative measures of carcass composition were evaluated as predictors of empty body protein (MTPRO) and lipid (MTLIP) mass. Empty body protein was predicted with similar accuracy (R2 = 0.74 to 0.81) from either DL, FFLM, LFSTIS, or ribbed carcass measurements. Empty body lipid was predicted more accurately from TOFAT (R2 = 0.92) or STLIP (R2 = 0.93) than ribbed carcass measurements (R2 = 0.88). Although the alternative measures of lean mass (LFSTIS vs FFLM) and lipid mass (TOFAT vs STLIP) were highly related to each other (r = 0.93 to 0.98), they had different relative growth rates (allometric coefficients) and thus cannot be predicted as linear functions of the similar alternative variable without significant weight group biases. From the 100- to 152-kg target weight groups, gilts gained 12.9% greater FFLM and 12.1% greater MTPRO but only 4.4% greater LFSTIS than barrows. Fat-free lean mass is more precise as a measure of muscle growth and as a predictor of lysine requirements. Lipid-free soft tissue can be obtained more quickly and predicted more accurately from carcass or live animal measurements.

Biases associated with genotype and sex in prediction of fat-free lean mass and carcass value in hogs.

Carcass and live measurements of 165 market hogs that represented seven genotypes were used to investigate genotype and sex biases associated with the prediction of fat-free lean mass (FFLM) and carcass value. Carcass value was determined as the sum of the product of weight of individual cuts and their average unit prices adjusted for slaughter and processing costs. Independent variables used in the prediction equations included carcass measurements, such as optical probe, midline ruler, ribbed carcass measurements, and electromagnetic scanning (EMSCAN), and live animal ultrasonic scanning. The effect of including subpopulation mean values of independent variables in the prediction equations for FFLM and carcass value was also investigated. Genotype and sex biases were found in equations in which midline backfat, ribbed carcass, EMSCAN, and live ultrasonic scanning were used as single technology sets of measurements. The prediction equations generally undervalued genotypes with above-average carcass value. Biases were reduced when measurements of combined technologies and mean adjusted variables were used. The FFLM and carcass value of gilts were underestimated, and they were overestimated of barrows. Equations that combined OP and EMSCAN technologies were the most accurate and least biased for both FFLM and carcass value. Equations that included carcass weight and midline last-rib backfat thickness measurements were the least accurate and most biased. Genotype and sex biases must be considered when predicting FFLM and carcass value.

DETERMINATION OF TOTAL BODY FAT

Mammalian body represents the sum of 2 major components: the body fat which varies widely from individual to individual, and fat-free lean mass (FFLM), which is of relatively constant weight in a healthy individual and is of relatively constant composition. Since adipose tissues are metabolically active, knowledge of total body fat could add significance to studies in fat metabolism. Measuring body fat can provide a means of studying the water content of fat-free lean mass (FFLM), under conditions of abnormal hydration or nutrition, and the changes that may occur with age. Lesser and co-workers¹report on the use of cyclopropane, a relatively safe anesthetic gas and at the same time highly fat-soluble, for the determination of total body fat in an experiment in a closed circuit. The method of study was as follows: A circular rubber diaphragm with a central aperture somewhat less than collar size was slipped over