Total Body Electrical Conductivity Method Research Articles

Effect of egg composition on hatchability and on growth and slaughter characteristics of meat-type chicks

1. Using the so-called TOBEC (Total Body Electrical Conductivity) method, which allows the determination of egg composition in vivo, correlations between egg composition, hatchability and hatched chicks’ development were studied. 2. A total of 1500 hen eggs (Ross-308) were measured by TOBEC, and eggs with extremely high (10%, n = 150), extremely low (10%, n = 150) and average (10%, n = 150) electrical conductivity values were chosen for further investigation. 3. During the incubation period, it was observed that eggs with high electrical conductivity had a significantly higher mortality than eggs with low electrical conductivity. 4. It was observed that both the increase in electrical conductivity at the same egg weight, and the increase in egg weight at the same electrical conductivity resulted in an increase in the hatching weight. 5. It was found that the dry matter, protein and fat content of the chicks hatched from eggs with low electrical conductivity was higher at hatching than that of the chicks hatched from eggs with high electrical conductivity. 6. At 42 d of age the liveweight of cocks and pullets hatched from eggs with low electrical conductivity was 3·2 and 8·2% higher than the liveweight of cocks and pullets hatched from eggs with high electrical conductivity. 7. Because of the higher liveweight at slaughter, there was a significant superiority of the chicks hatched from eggs with low electrical conductivity in the case of the examined carcase traits at slaughter. 8. Similar tendencies were found also in the ratios of carcase variables to liveweight, but the between group differences were not statistically significant in this case. 9. Based on the results it was concluded that TOBEC seems to be a useful method for separating eggs with different composition. 10. This could be a good starting point for further in vivo investigations in order to clarify the effect of egg composition on hatchability and further development.

Comparison of the slaughter characteristics of meat-type chicks hatched from eggs with different composition

Using the so-called TOBEC (Total Body Electrical Conductivity) method for the in vivo determination of egg composition, the effect of egg composition on the slaughter characteristics of hatched chicks was examined in the ROSS-308 meat-type genotype. Chicks hatched from eggs with low, average and high electrical conductivity were slaughtered at 42 days of age. It was found that the weight of all of the examined traits showed highest values in the case of chicks hatched from eggs with low electrical conductivity, while the lowest values could be observed in the case of chicks hatched from eggs with high electrical conductivity. Similar tendencies were observed also in the case of the ratio of the examined slaughter traits to the slaughter weight, but in this case the differences were not statistically proven (P>0.05).

In vivo measurement of total body lipid content of common carp (<i>Cyprinus carpio</i> L.) by electrical conductivity

Abstract. non-destructive method to predict the total lipid content and the lean body mass (LBM) was evaluated by measuring the total body electrical conductivity (TOBEC) with common carp. This technique is based on the principle that body fat and fat-free mass differ in electric properties which can be measured in a low-frequency electromagnetic field. Experimental fish with average body weight of 1225 ± 298 g originated from a commercial stock. Fish were slaughtered immediately after the measurements and homogenized samples were taken from the grinded whole-body. The fat content of the homogenates was analysed using Soxhlet extraction after hydrochloric acid digestion. The weight of lean body mass (LBM) was calculated as the difference between the live weight and the weight of fat determined. The TOBEC method provided very precise estimation of lean body mass (R2 = 0.99). Total body lipid content (in gram) can also be predicted from the E value and live weight with adequate accuracy (R2 = 0.66) in the size range of 706–1989 g in common carp. The predictibility of the crude fat content (in %) was moderate (R2 = 0.37) in the present investigation. It could not be increased significantly by including other body measurements as standard lenght, height and circumference. Fat content of table-sized, sexually matured common carp can be estimated at a precision level that may be adequate only if high selection pressure has to be applied in a breeding program.

Does the BMI reflect body fat in obese children and adolescents? A study using the TOBEC method.

Due to the fact that obesity is defined as excess of body fat mass, we tested the hypothesis whether the body mass index (BMI) can be used as a valid measure for the detection of the degree of obesity in individual obese children and adolescents. A total of 204 obese children and adolescents (105 boys, 99 girls) aged 6-17 y, using total body electrical conductivity (TOBEC) for fat measurement, were included into this study. A multiple regression analysis was performed with percentage body fat (PBF) as dependent variable and BMI, age and sex as independent variables. First- and second-order interaction terms were also included. Since all interaction terms showed a significant influence on PBF, regression analysis was performed separately for boys and girls, dividing each group into two age subgroups (subjects younger than 10 y, and subjects 10 y or older). BMI and PBF were observed to be positively correlated (overall: r=0,65; P=0.0001; boys r=0.63 and girls: r=0.68). Through a multiple regression analysis 57% of the variance of PBF could be explained by the independent variables. In boys younger than 10 y 73% and in girls younger than 10 y 63% of the variance of PBF was explained by the BMI. In subjects 10 y or older the association was poor (boys: 27%; girls: 38%). It should be emphasized that there is a wide range in the relationship between PBF and BMI in the obese subjects. From these results we conclude that BMI might be a useful parameter for epidemiological studies: however in the individual pediatric patient, especially from 10 y onwards, it gives only a limited insight to the degree of obesity based on the definition.

Evaluation of the TOBEC Method for Calculating Fat Mass in Tree SparrowsPasser montanusand House SparrowsPasser domesticus

Abstract. Total body electrical conductivity (TOBEC) is the name of a non-invasive method for investigating total body fat (TBF) in vertebrates. The error of measurement depends on body mass (for large animals the relative error is small), body shape and other factors. The ACAN-2 apparatus operating on the basis of the TOBEC method shows integer numbers (readings) correlated with lean body mass (LBM). From the series of these readings (measurements) TOBEC can be calculated in many ways. The error for LBM and TBF measurements in Tree Sparrows (of masses 22.5 ± 1.7 g) and House Sparrows (of masses 29.8 ± 2.0 g) was 1.19 g. This error may be reduced by repeating the TOBEC measurement and calculating the arithmetic mean of readings from the apparatus obtained 1 second after the commencement of measurement. Readings making up a single measurement series showed periodic irregular fluctuations of average amplitude 3 units in the case of Tree Sparrows and 5 units for House Sparrows — corresponding to errors of 0....

Nutritional aspects of chronic liver disease and liver transplantation in children.

Nutritional aspects of chronic liver disease and liver transplantation in children.

Ever higher: Constant rise of body weight set-point in growing Zucker rats

The mass of food hoarded by rats given access to food only 2 h per day is proportional to the rats' body weight deficit. The intersect of the regression line of hoarded food plotted against body weight gives an indication of the body weight set-point. In the present work, the hoarding behavior of six obese and six control rats was measured every day at various body weights from 8 to 24 weeks of age. Every other week the animals were anesthetized and their percentage of fat was measured in vivo with a total body electrical conductivity method (TOBEC). Lean mass and body length of the obese, and their controls, increased similarly in both groups over the period of the measurements. On the other hand, the body weights increased more in obese, from 174 ± 5 to 729 - 18 g ( n = 6), than in controls, from 157 ± 5 g to 452 ± 14 g ( n = 6). The body weight set-point, calculated every other week for both groups of rats, increased progressively with age. At the age of 24 weeks, the mean set-point for body weight regulation was 758 ± 13 g in obese and 467 ± 12 g in controls. This result suggests that the obese fa/fa rat defends its fat content, or a variable correlated to the fat content.

Ever Higher: Constant Rise of Body Weight Set-Point in Growing Zucker Rats

The mass of food hoarded by rats given access to food only 2 h per day is proportional to the rats' body weight deficit. The intersect of the regression line of hoarded food plotted against body weight gives an indication of the body weight set-point. In the present work, the hoarding behavior of six obese and six control rats was measured every day at various body weights from 8 to 24 weeks of age. Every other week the animals were anesthetized and their percentage of fat was measured in vivo with a total body electrical conductivity method (TOBEC). Lean mass and body length of the obese, and their controls, increased similarly in both groups over the period of the measurements. On the other hand, the body weights increased more in obese, from 174 ± 5 to 729 - 18 g ( n = 6), than in controls, from 157 ± 5 g to 452 ± 14 g ( n = 6). The body weight set-point, calculated every other week for both groups of rats, increased progressively with age. At the age of 24 weeks, the mean set-point for body weight regulation was 758 ± 13 g in obese and 467 ± 12 g in controls. This result suggests that the obese fa/fa rat defends its fat content, or a variable correlated to the fat content.

Comparison of Condition Indices in Migratory Passerines at a Stopover Site in Coastal Louisiana

We evaluated the utility of four nondestructive condition indices-body mass, body mass scaled by wing chord length, fat scoring, and total body electrical conductivity method (TOBEC) ― as predictors of lipid levels in migrating Wood Thrushes (Hylocichla mustelina), Swainson's Thrushes (Catharus ustulatus), and Summer Tanagers (Piranga rubra). The Red-winged Blackbird (Agelaius phoeniceus), a winter resident, was examined for comparative purposes. In addition, we examined differences among species in relationships of total body lipids and condition indices. Body mass was the best index of lipid levels, explaining 36%-82% of the variation in total body lipids in all four species. The relative contributions of the other indices to the prediction of lipid mass varied among species although TOBEC was selected for inclusion in each regression equation. For two species, equations including TOBEC measurements had lower errors in lipid prediction than equations only using the other nondestructive indices. Errors in lipid prediction were large for all the regression equations based on condition indices. In many cases it will be necessary to develop species-specific equations to predict lipid levels with condition indices

New way of body composition analysis using total body electrical conductivity method

Traditional methods of measuring total body water and fat content of animals that require sacrificing specimens are generally unacceptable when endangered species, or large animal sizes, or humans are involved. These methods are also unsuitable for following changes of fat and water content in individuals. An alternative method, based on the nonresonant absorption of a rf electromagnetic field has been used for constructing a new body composition analyzer. As the electrical conductivity of lipids is approximately 20 times lower than that of lean tissues, the rf power absorbed by the animal provides information which enables one to calculate the lean body mass and total body water. The new instrument measures rf power absorbed by an animal by measuring the quality factor (Q) of the resonant circuit with an animal placed inside the coil. Numerical calculations of the rf power absorbed by a cylindrical object containing 0.9% NaCl aqueous solution have also been performed. Experimental values confirmed the calculated dependence of the absorbed power on the cylinder radius. The device built has been calibrated on 9 males and 11 females of laboratory mice. The amount of lipids was then measured by ether extraction. The relation between instrument reading, which is proportional to the power absorption, and lean body mass (LBM) or water mass (WM) was linear and highly significant: the simple regression coefficients of determination were 0.983 for LBM, and 0.990 for WM (p<0.001). It has been found that for an individual animal with a body mass ranging from 15.9 to 40.7 g, the accuracy of measurement was ±1.6 g for LBM and ±1 g for WM.

Food Restriction Effects on the Body Composition of Free-Living Ground Squirrels,Spermophilus beldingi

I conducted a field experiment to examine the use of body fat as an energy reserve by juvenile female Belding's ground squirrels, Spermophilus beldingi, prior to hibernation. Squirrels were divided into two groups: the squirrels in one group had their foraging times restricted by being placed in a cage for part of each day for four consecutive days (deprived group), and the squirrels in the other group foraged ad lib. (ad lib. group). The deprived group foraged in its normal habitat morning and evening but had access only to water and lettuce while captive. Total body electrical conductivity (TOBEC), an in vivo method of estimating fat-free mass, was used to follow changes in body composition. The deprived group lost mass, while the ad lib. group gained mass. Total body electrical conductivity measurements indicated that the deprived group lost fat-free mass and not fat, whereas mass gained by the ad lib. group was mostly fat. This is consistent with an emphasis on fat anabolism prior to hibernation. I also show that the TOBEC method is affected by variation in stomach contents, and I evaluate conditions under which an intraspecific calibration equation is needed

Total-body electrical conductivity method for estimating body composition: validation by direct carcass analysis of pigs

Determination of body composition by measuring total-body electrical conductivity (TOBEC) is based on the principle that body fat and fat-free mass (FFM) differ in electrical properties. In humans, we are able to estimate body composition only by indirect methods, which have been used to validate the TOBEC instrument. Relationships between TOBEC and body composition were examined using direct carcass analysis of 24 pigs differing widely in body weight and composition (48-137 kg and 14-45% fat, respectively). Highly significant correlations (p less than 0.0001) were found between body conductivity and empty-body water (H2O) (r = 0.979), empty-body FFM (r = 0.980), empty-body crude protein (r = 0.962), and empty-body potassium (r = 0.949). Prediction of empty-body H2O or FFM from TOBEC had a SEE of 2.1 or 2.8 kg, respectively. Thus, the TOBEC method can predict body H2O and FFM over a wide range of body weight and fatness.

Total body electrical conductivity used to determine body composition in infants.

Total body electrical conductivity (TOBEC) has been introduced as a rapid, safe, and noninvasive method suitable for the estimation of fat-free mass. The instrument (EMME or TOBEC) operates on the principle that organisms placed in an electromagnetic field perturb the field to a degree that depends on the amount and volume of distribution of electrolytes present. A study was designed to measure body composition in infants by the TOBEC method and to compare the results with those obtained using the isotope dilution technique. Sixteen infants (age range, 2 days to 9.7 months; weight range, 2 to 8.7 kg) were enrolled. Total body water (TBW) was determined by the isotope dilution technique using H218O. There was a good correlation between the natural logarithm of the TOBEC number and TBW, with a linear correlation coefficient of 0.949. The fat-free body mass of the infants was calculated by TBW (fat-free body mass = /0.082) and by the TOBEC method using the standard previously derived from mature rabbits. TBW measurements by H218O dilution appeared to overestimate fat-free mass which was greater than TBW in five of the 16 infants. Measured by the TOBEC method, fat-free mass ranged from 51 to 91% of total body weight. The TOBEC method is highly suitable for use with human infants and appears to determine body composition as accurately as other available methods.

Estimation of human body composition by electrical impedance methods: a comparative study

This study 1) further validated the relationship between total body electrical conductivity (TOBEC) and densitometrically determined lean body mass (LBMd) and 2) compared with existing body composition techniques (densitometry, total body water, total body potassium, and anthropometry) two new electrical methods for the estimation of LBM: TOBEC, a uniform current induction method, and bioelectrical impedance analysis (BIA), a localized current injection method. In a sample of 75 male and female subjects ranging from 4.9 to 54.9% body fat the correlation between LBMd and LBM predicted from TOBEC by use of a previously developed regression equation was extremely strong (r = 0.962), thus confirming the validity of the TOBEC method. LBM predicted from BIA by use of prediction equations provided with the instrument also correlated with LBMd (r = 0.912) but overestimated LBM compared with LBMd in obese subjects. However, no such systematic error was apparent when new prediction equations derived from this heterogeneous sample of subjects were applied. Thus the TOBEC and BIA methods, which are based on the differing electrical properties of lean tissue and fat and which are convenient, rapid, and safe, correlate well with more cumbersome human body composition techniques.

Comparison in man of total body electrical conductivity and lean body mass derived from body density: Validation of a new body composition method

This article reports a study in which total body electrical conductivity (TOBEC) measurements and lean body mass (LBM) estimated from hydrostatic weighing in human subjects were compared. The TOBEC method provides a new approach to assessment of human body composition that is based on the principle that the electrical conductivity of lean tissue is far greater than that of fat. In a sample of 32 men and women varying widely in age (20 to 53 years), body weight (45 to 155 kg), and adiposity (9.5 to 53.0% body fat), the TOBEC measurement was found to be extremely reliable ( r = 0.999) and to correlate highly with hydrostatically estimated LBM ( r = 0.903, P < 0.0001). When the TOBEC scores were transformed to provide a single variable; namely, the subject's height times the square root of the TOBEC score, a higher correlation with LBM was obtained ( r = 0.943). Taking gender into account further enhanced the prediction of LBM from TOBEC ( r = 0.951). These observations strongly reinforce the results of a previous investigation in which high correlations were found between TOBEC and both total body potassium and total body water. Accordingly, this new method promises to provide a useful technique for the evaluation of body composition that is at once simple, rapid, objective, and noninvasive.