Body weight, metabolic rate, and trace substance turnover in animals

Oecologia ◽  
1977 ◽  
Vol 29 (2) ◽  
pp. 99-104 ◽  
Author(s):  
T. Fagerström
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Trace Substance

Some consequences of body size

1984 ◽  
Vol 247 (4) ◽  
pp. H495-H507 ◽  
Author(s):  
L. E. Ford
Keyword(s):  
Heart Rate ◽  
Body Weight ◽  
Metabolic Rate ◽  
Muscle Power ◽  
Weight Ratio ◽  
Single Species ◽  
Hill Climbing ◽  
Proper Size ◽  
Higher Power ◽  
Metabolic Indices

The question of the proper size denominator for metabolic indices is addressed. Metabolic rate among different species is proportional to the 3/4 power of body weight, not surface area. Muscle power also varies with the 3/4 power of weight, suggesting that metabolic rate is determined mainly by muscle power. Power-to-weight ratio, specific metabolic rate, and a number of metabolic periods, including heart rate, all vary inversely with the 1/4 power of body weight. Thus the relative times required for physiological and pathological processes in different species may be estimated from the average resting heart rate for the species. There are not many small humans among athletic record holders in events involving acceleration and hill climbing, as would be expected if they had higher power-to-weight ratios. Thus the relationship between size and metabolic rate in different species should not be applied within the single species of humans. Evidence is reviewed showing that basal metabolic rate in humans is determined mainly by lean body mass.

Respiratory Exchange and Body Size in the Aldabra Giant Tortoise

1971 ◽  
Vol 55 (3) ◽  
pp. 651-665 ◽  
Author(s):  
G. M. HUGHES ◽  
R. GAYMER ◽  
MARGARET MOORE ◽  
A. J. WOAKES
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Relative Proportion ◽  
The Body ◽  
O2 Consumption ◽  
Weight Range ◽  
Testudo Hermanni ◽  
The Mean ◽  
Good Agreement

1. The O2 consumption and CO2 release of nine giant tortoises Testudo gigantea (weight range 118 g-35·5 kg) were measured at a temperature of about 25·5°C. Four European tortoises Testudo hermanni (weight range 640 g-2·16 kg) were also used. The mean RQ values obtained were 1·01 for T. gigantea and 0·97 for T. hermanni. These values were not influenced by activity or size. 2. The data was analysed by plotting log/log regression lines relating body weight to O2 consumption. Both maximum and minimum metabolic rates recorded for each individual T. gigantea showed a negative correlation with body weight. For active rates the relation was O2 consumption = 140·8W0·97, whereas for inactive animals O2 consumption = 45·47W0·82. 3. The maximum rates were obtained from animals that were observed to be active in the respirometer and the minimum rates from animals that remained quiet throughout. The scope for activity increased with body size, being 82 ml/kg/h for animals of 100 g and 103 ml/kg/h for 100 kg animals. The corresponding ratio between maximum and minimum rates increases from about 2 to 6 for the same weight range. 4. Values for metabolic rate in T. hermanni seem to be rather lower than in T. gigantea. Analysis of the relative proportion of the shell and other organs indicates that the shell forms about 31% of the body weight in adult T. hermanni but only about 18% in T. gigantea of similar size. The shell is not appreciably heavier in adult T. gigantea (about 20%). 5. Data obtained for inactive animals is in good agreement with results of other workers using lizards and snakes. Previous evidence suggesting that chelonians show no reduction in metabolic rate with increasing size is not considered to conflict with data obtained in the present work.

METABOLIC REFERENCE STANDARDS FOR THE NEONATE

PEDIATRICS ◽  
1967 ◽  
Vol 39 (5) ◽  
pp. 724-732
Author(s):  
John C. Sinclair ◽  
Jon W. Scopes ◽  
William A. Silverman
Keyword(s):  
Body Composition ◽  
Body Weight ◽  
Oxygen Consumption ◽  
Metabolic Rate ◽  
Extracellular Fluid ◽  
Mean Value ◽  
Reference Standards ◽  
Contributory Factor ◽  
Tissue Mass ◽  
Rate Of Oxygen Consumption

Oxygen consumption of 92 normally grown newborn babies of birth weight 750 to 3,940 gm has been expressed in terms of various metabolic reference standards in order to identify any systematic variation in expression of metabolic rate that is introduced by these bases of reference in the newborn population. It is postulated that differences in body composition comprise a contributory factor to the variation among newborn babies in rate of oxygen consumption per kilogram body weight. The predictive error from a mean value is increased if surface area, body weight, or fat-free body weight is substituted for body weight as a metabolic reference standard. By taking into account known changes in body composition of the fetus with increasing maturity, a compartment representing the active tissue mass is calculated. This corresponds closely to body weight minus extracellular fluid and includes fat. Rate of oxygen consumption is proportional to the size of this compartment over the range of body weights studied. Implications are discussed as to the metabolic rate of adipose tissue in the newborn and body composition among undergrown babies.

Metabolic Rate of Female Rats as a Function of Age and Body Size

1956 ◽  
Vol 186 (1) ◽  
pp. 9-12 ◽  
Author(s):  
Max Kleiber ◽  
Arthur H. Smith ◽  
Theodore N. Chernikoff
Keyword(s):  
Body Weight ◽  
Body Size ◽  
Metabolic Rate ◽  
Age Groups ◽  
Female Rats ◽  
Standard Errors ◽  
Normal Female ◽  
Metabolic Rates ◽  
The Mean ◽  
Specific Unit

On the basis of 926 respiration trials, metabolic rates of normal female rats are presented as means of 42 different age groups from birth to 1000 days of age. The means with their standard errors are given for the metabolic rates per rat, per kilogram weight, per unit of the 2/3 power of body weight (surface), and per unit of the 3/4 power of body weight (inter specific unit of metabolic body size). A minimum of 72.6 Cal/kg.3/4 occurs between the ages of 200 and 300 days. An equation with two exponentials predicts the metabolic rate of rats from 77–1000 days of age with a standard deviation between prediction and observation of 2.2% of the mean.

Regulation of metabolic rate in Svalbard and Norwegian reindeer

1984 ◽  
Vol 247 (5) ◽  
pp. R837-R841 ◽  
Author(s):  
K. J. Nilssen ◽  
J. A. Sundsfjord ◽  
A. S. Blix
Keyword(s):  
Body Weight ◽  
Critical Temperature ◽  
Food Intake ◽  
Metabolic Rate ◽  
Seasonal Changes ◽  
Serum Levels ◽  
Physiological Adaptation ◽  
Conservation Of Energy ◽  
Winter Food ◽  
Lower Critical Temperature

Food intake, body weight, serum levels of triiodothyronine (T3) and free thyroxine (FT4), and metabolic rate were measured at intervals in Svalbard (SR) and Norwegian (NR) reindeer. From summer to winter food intake decreased 57 (SR) and 55% (NR), while body weight decreased 8.6 (SR) and 3.8% (NR). In SR T3 and FT4 changed seasonally, whereas this was only evident for T3 in NR. Resting (standing) metabolic rate (RMR) in winter was 1.55 (SR) and 2.05 W X kg-1 (NR), lower critical temperature (TLC) being -50 (SR) and -30 degrees C (NR). RMR in summer was 2.15 (SR) and 2.95 W X kg-1 (NR), TLC being -15 (SR) and 0 degrees C (NR). Seasonal changes in T3 and FT4 did not coincide with changes in food intake or RMR in either SR or NR. RMR did, however, correlate with food intake. This indicates that seasonal changes in RMR are due to the thermic effects of feeding and represent no physiological adaptation aimed at conservation of energy during winter.

SOME PHYSIOLOGICAL AND NUTRITIONAL ASPECTS OF THE DWARF CHICKEN

1971 ◽  
Vol 51 (1) ◽  
pp. 209-216 ◽  
Author(s):  
G. RAJARATNAM ◽  
J. D. SUMMERS ◽  
A. S. WOOD ◽  
E. T. MORAN Jr.
Keyword(s):  
Body Weight ◽  
Oxygen Consumption ◽  
Weight Gain ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Body Weight Gain ◽  
Carcass Composition ◽  
Lower Body ◽  
Brand Name ◽  
Dwarf Chicken

A study was undertaken to investigate the feasibility of hypothyroidism as an explanation for the smaller body size and lower metabolic activity of the recessive sex-linked dwarf chicken. A significant increase in body weight gain and feed intake for dwarf chicks with little change in these parameters for normal chicks receiving a diet supplemented with Protamone (brand name for iodinated casein) suggests a hypothyroidic state for the dwarfs. Similarly, a significantly lower body temperature, oxygen consumption and basal metabolic rate with a higher percentage of carcass fat in dwarf chicks as compared with normal ones supports the above hypothesis. Protamone supplementation of the diet increased body temperature and metabolic rate, and altered the carcass composition of the dwarfs to values closer to that of normal chicks, again suggesting a low thyroxine output for the dwarfs.

Effects of exercise on fluid exchange and body composition in man during 14-day bed rest

1977 ◽  
Vol 43 (1) ◽  
pp. 126-132 ◽  
Author(s):  
J. E. Greenleaf ◽  
E. M. Bernauer ◽  
L. T. Juhos ◽  
H. L. Young ◽  
J. T. Morse ◽  
...  
Keyword(s):  
Body Weight ◽  
Metabolic Rate ◽  
Lean Body Mass ◽  
Body Mass ◽  
Body Position ◽  
Isometric Exercise ◽  
Bed Rest ◽  
The Body ◽  
Fluid Exchange ◽  
Isotonic Exercise

To determine the cause of the body weight loss during bed rest (BR), fluid balance and anthropometric measurements were taken from seven men (19–21 yr) during three 2-wk BR periods which were separated by 3-wk ambulatory recovery periods. Caloric intake was 3,073 +/- 155 (SD) kcal/day. During two of the three BR periods they performed supine isotonic exercise at 68% of VO2max on the ergometer for 1 h/day; or supine isometric exercise at 21% of maximal leg extension force for 1 min followed by a 1-min rest for 1 h/day. No prescribed exercise was given during the other BR period. During BR, body weight decreased slightly with no exercise (-0.43 kg, NS), but decreased significantly (P less than 0.05) by -0.91 kg with isometric and by -1.77 kg with isotonic exercise. About one-third of the weight reduction with isotonic exercise was due to fat loss (-0.69 kg) and, the remainder, to loss of lean body mass (-0.98 kg). It is concluded that the reduction in body weight during bed rest has two major components: First, a loss of lean body mass caused by assumption of the horizontal body position that is independent of the metabolic rate. Second, a loss of body fat content that is proportional to the metabolic rate.

Whole Body Protein Turnover in Chronically Undernourished Individuals

1994 ◽  
Vol 86 (4) ◽  
pp. 441-446 ◽  
Author(s):  
M. J. Soares ◽  
L. S. Piers ◽  
P. S. Shetty ◽  
A. A. Jackson ◽  
J. C. Waterlow
Keyword(s):  
Body Weight ◽  
Protein Synthesis ◽  
Metabolic Rate ◽  
Muscle Mass ◽  
Basal Metabolic Rate ◽  
Normal Weight ◽  
Fat Free Mass ◽  
Whole Body ◽  
Body Protein ◽  
Chronic Undernutrition

1. Two groups of adult men were studied in Bangalore, India, under identical conditions: the ‘normal weight’ subjects (mean body mass index 20.8 kg/m2) were medical students of the institute with access to habitual energy and protein intakes ad libitum. The other group, designated ‘undernourished’, were labourers on daily wages (mean body mass index 16.7 kg/m2). 2. In an earlier study we obtained lower absolute values for both basal metabolic rate and protein synthesis in the undernourished subjects; however, when the data were expressed on a body weight or fat-free mass basis, a trend towards higher rates of protein synthesis, as well as higher basal metabolic rate, was evident. The suggestion was made that such results reflected the relatively higher energy intakes per kg body weight of the undernourished subjects on the day of study. The objective of the present study was therefore to control for the dietary intake during the measurement of whole body protein turnover. 3. In the present study dietary intakes were equated on a body weight basis; however, expressed per kg fat-free mass, the normal weight subjects had received marginally higher intakes of energy and protein. The results, however, were similar to those of the previous study. In absolute terms, basal metabolic rate, protein synthesis and breakdown were lower in the undernourished subjects. When expressed per kg body weight or per kg fat-free mass, the undernourished subjects had higher basal metabolic rates than the well-nourished subjects, whereas no differences were seen in the rate of protein synthesis or breakdown. 4. Estimates of muscle mass, based on creatinine excretion, indicated that the undernourished subjects had a higher proportion of non-muscle to muscle mass. Nitrogen flux (Q) was determined from 15N abundance in two end products, urea (Qu) and ammonia (Qa). The ratio Qu/Qa was increased in the undernourished subjects and was significantly correlated with the ratio of non-muscle to muscle mass (r = 0.81; P < 0.005). These results fit in with our earlier suggestion of a greater proportion of non-muscle (visceral) mass in undernourished subjects. 5. The present data suggest that there are no changes in the rate of protein synthesis or breakdown in chronic undernutrition when results are expressed, conventionally, per kg fat-free mass. It can be theoretically shown, however, that there could be a 15% reduction in the rate of turnover of the visceral tissues in chronic undernutrition. This, together with the reduced urinary nitrogen excretion, would contribute to nitrogen economy in these individuals.

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