The Developmental Efficiency of the Avian Embryo

1927 ◽  
Vol 5 (1) ◽  
pp. 43-54
Author(s):  
JOSEPH NEEDHAM
Keyword(s):  
Growth Rate ◽  
Metabolic Rate ◽  
Basal Metabolism ◽  
Energetic Efficiency ◽  
Avian Embryo ◽  
Efficiency Coefficient

1. The "Coefficient d'Utilisation" or Plastic Efficiency Coefficient (P.E.C.) has been calculated for each day during development. It has a trough which is deepest between the eighth and ninth days; development is therefore most expensive at this point. The correlation between this and the point of greatest intensity of protein combustion is exact. 2. The "Rendement Energétique brut" or Apparent Energetic Efficiency has been calculated for each day during development. It rises, changing more rapidly towards the end than at the beginning; thus it resembles the metabolic rate rather than the growth rate. The "Rendement Energétique réel" or Real Energetic Efficiency cannot at present be calculated for the basal metabolism of the embryo is unknown and it is not certain whether the usual conceptions of basal metabolism can be applied to a rapidly growing and changing organism.

Stability of basal metabolic rate on a polar expedition

1961 ◽  
Vol 16 (3) ◽  
pp. 397-400 ◽  
Author(s):  
H. E. Lewis ◽  
J. P. Masterton ◽  
S. Rosenbaum
Keyword(s):  
Young Adults ◽  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Field Work ◽  
Basal Metabolism ◽  
The Arctic ◽  
Polar Regions ◽  
Exposure To Cold ◽  
Efficient Protection ◽  
At Home

The basal metabolism studied in 29 young adults on 349 occasions over 2 years in the Arctic was 37.4 (sd α 3.7) kcal/m-2/hr-1, and well within the normal British standards. The variability showed no relationship to season. On polar expeditions, men's physiologically significant exposure to cold is small because of efficient protection by clothing and shelter. Information is needed about precise differences of microclimate in the polar regions and at home. Field work could more profitably be directed to the cognate problem of costs of various activities in the cold rather than basal metabolic rate. Submitted on April 25, 1960

Factors regulating basal metabolism of the isolated perfused rabbit heart

1986 ◽  
Vol 250 (6) ◽  
pp. H998-H1007 ◽  
Author(s):  
C. L. Gibbs ◽  
G. Kotsanas
Keyword(s):  
Metabolic Rate ◽  
Coronary Flow ◽  
Constant Pressure ◽  
Rabbit Heart ◽  
Basal Metabolism ◽  
Papillary Muscles ◽  
O2 Consumption ◽  
Calcium Depletion ◽  
Experimental Conditions ◽  
High K

Basal metabolism has been measured in isolated whole hearts from rabbits and compared with myothermic and polarographic measurements on isolated papillary muscles. Hearts were perfused at constant pressure (Langendorff method) using a modified Krebs-Henseleit solution (KH) with glucose as substrate. Higher levels of basal O2 consumption (MVO2) and coronary flow (CF) were observed when arrest was induced by calcium depletion (low Ca; 0.1 mM CaCl2, 10.0 mM KCl) rather than by potassium excess (high K; 30.0 mM KCl). The metabolic rate of high K arrested hearts was close to earlier myothermic estimates (J. Mol. Cell. Cardiol. 16: 953-962, 1984); polarographic values, however, were about twofold higher, and somewhat higher than the value obtained in low Ca arrested hearts. The addition of erythrocytes, albumin, or dextran significantly reduced CF but did not substantially alter basal MVO2. Basal metabolic rate was substrate- and O2 tension-dependent, and under all experimental conditions there was linear relationship between MVO2 and CF. Extrapolations to zero flow showed that the basal MVO2 values so obtained were similar in low Ca or high K and were not altered by the presence of erythrocytes. Our results show that there are several factors regulating basal metabolism.

Issues arising from genetic selection for growth and body composition characteristics in poultry and pigs

2000 ◽  
Vol 27 ◽  
pp. 39-53 ◽  
Author(s):  
G. C. Emmans ◽  
I. Kyriazakis
Keyword(s):  
Growth Rate ◽  
Body Composition ◽  
Metabolic Rate ◽  
Support Systems ◽  
Genetic Selection ◽  
Fitness Traits ◽  
Environmental Requirements ◽  
Selection For ◽  
Rate Selection ◽  
Composition Characteristics

AbstractBreeders of poultry and pigs have selected for some combination of increased growth rate, decreased fatness and increased muscularity. Increasingly various fitness traits are included in the index used. The consequences of such selection include complex effects on nutritional and environmental requirements, at least some of which are reliably predictable using suitable models. Appropriate changes to the environment and to nutrition as selection proceeds will help to avoid unwanted effects occurring. Among the predictable effects are that higher ratios of nutrients to energy, and lower temperatures, will be needed by the improved genotypes. Selection for growth rate must eventually exhaust the capacity of the support systems – digestive, respiratory, circulatory and excretory – to cope with the increased metabolic rate. Selection for increased yield of valuable parts will cause these problems to occur earlier. While it is possible to predict that these problems will occur it cannot be predicted when they will. Breeders need to be aware of these problems, and use all possible routes to help them in reducing their severity. Where the appropriate actions for fitness selection, and nutritional and environmental modifications, are taken the occurrence of the problems will be delayed.

scholarly journals Laboratory Metabolism of Incubating Semipalmated Plovers

The Condor ◽  
2006 ◽  
Vol 108 (4) ◽  
pp. 966-970
Author(s):  
Mark Williamson ◽  
Joseph B. Williams ◽  
Erica Nol
Keyword(s):  
Critical Temperature ◽  
Metabolic Rate ◽  
Breeding Season ◽  
Basal Metabolic Rate ◽  
Low Temperatures ◽  
Thermal Conductance ◽  
Basal Metabolism ◽  
The Arctic ◽  
Lower Critical Temperature ◽  
Metabolic Data

Abstract Abstract The Semipalmated Plover (Charadriussemipalmatus), anarctic-nesting migratory shorebird, regularlyencounters low temperatures during the breedingseason. We measured the basal metabolism of adultsduring incubation at Churchill, Manitoba, Canada todetermine basal metabolic rate (BMR),lower critical temperature(Tlc), total evaporative waterloss (TEWL), and dry thermal conductance(Cm). BMR and Tlcwere 47.4 kJ day−1and 23.3°C, respectively, TEWL was2.5 mL H2O−d,and Cm was1.13 mW g−1 °C−1.Measured BMR and Tlc were consistentwith high values found for other shorebird speciesbreeding in the Arctic, while Cm was18% higher than predicted from allometricequations. These metabolic data suggest thatSemipalmated Plovers are adapted to balance therequirements of incubation against energetic andthermoregulatory demands in the Arctic, especiallyin harsh early breeding season conditions.

Basal metabolism and respiration in men living at 5,800 m (19,000 ft)

1964 ◽  
Vol 19 (5) ◽  
pp. 949-954 ◽  
Author(s):  
M. B. Gill ◽  
L. G. C. E. Pugh
Keyword(s):  
Metabolic Rate ◽  
Basal Metabolic Rate ◽  
Basal Respiration ◽  
Mean Value ◽  
Alveolar Ventilation ◽  
Basal Metabolism ◽  
South American ◽  
Insufficient Evidence ◽  
Prolonged Stay ◽  
The Mean

Respiratory determinations were carried out on eight members of the Himalayan Scientific and Mountaineering Expedition 1960—1961 and three Sherpas during a prolonged stay at 5,800 m (19,000 ft). Ventilation and oxygen uptake were similar in both groups, although the Sherpas were smaller men. The Sherpas had lower alveolar ventilation, higher PaCOCO2 and lower PaOO2 values than the scientists. Among six of the scientists mean basal metabolic rate was 10% above the mean value predicted from sea-level standards. There was no increase in the two others, who did not acclimatize. The mean basal metabolic rate in the three Sherpas was +21%. The findings were not explained by the extra O2 cost of increased breathing, changes in body composition, or exposure to cold, although this may have been a factor in the Sherpas. The results were similar to recent South American data on residents at 4,540 m (14,900 ft). It was concluded that acclimatization to great altitudes in man is associated with increase in basal metabolism, but there is insufficient evidence as to whether this is a response to hypoxia or other environmental factors. basal respiration; acclimatized men; high altitude (5,800 m) Submitted on March 30, 1964

Age Changes in Body Size, Body Composition and Basal Metabolism

1956 ◽  
Vol 186 (2) ◽  
pp. 207-210 ◽  
Author(s):  
M. C. Conrad ◽  
A. T. Miller
Keyword(s):  
Body Composition ◽  
Body Size ◽  
Metabolic Rate ◽  
Relative Weight ◽  
Extracellular Fluid ◽  
The Body ◽  
Basal Metabolism ◽  
Albino Rats ◽  
Tissue Mass ◽  
Bone Minerals

The interrelations of body size, body composition and basal metabolism were studied in 69 albino rats ranging in age from 18–174 days. The decline in metabolic rate with age was more rapid than would be predicted from the weight0.75 rule which eliminates the influence of body size in interspecific measurements. Body composition analyses indicated that the increase with age in metabolically inert fat and bone minerals was approximately balanced by a corresponding decrease in metabolically inert extracellular fluid, so that ‘active tissue mass’ was virtually unchanged. Calculations based on data in the literature indicate that about one-half the decline in metabolic rate with age may be due to the corresponding decrease in the relative weight of the viscera. The remainder of the decline in metabolic rate must be due to factors other than changes in the chemical or histological composition of the body.

scholarly journals Scaling of statically derived osteocyte lacunae in extant birds: implications for palaeophysiological reconstruction

2019 ◽  
Vol 15 (4) ◽  
pp. 20180837 ◽  
Author(s):  
Orvil Grunmeier ◽  
Michael D. D'Emic
Keyword(s):  
Growth Rate ◽  
Metabolic Rate ◽  
Genome Size ◽  
Body Mass ◽  
Bird Species ◽  
Growth Rate Constant ◽  
Osteocyte Lacunae ◽  
Osteocyte Lacuna ◽  
The Relationship ◽  
Osteocyte Lacunar

Osteocytes are mature versions of osteoblasts, bone-forming cells that develop in two ways: via ‘static’ osteogenesis, differentiating and ossifying tissue in situ to form a scaffold upon which other bone can form, or ‘dynamic’ osteogenesis, migrating to infill or lay down bone around neurovasculature. A previous study regressed the volume of osteocyte lacunae derived from dynamic osteogenesis (DO) of a broad sample of extant bird species against body mass, the growth rate constant ( k ), mass-specific metabolic rate, genome size, and erythrocyte size. There were significant relationships with body mass, growth rate, metabolic rate, and genome size, with the latter being the strongest. Using the same avian histological dataset, we measured over 3800 osteocyte lacunar axes derived from static osteogenesis (SO) in order to look for differences in the strength of form–function relationships inferred for DO-derived lacunae at the cellular and tissue levels. The relationship between osteocyte lacunar volume and body mass was stronger when measuring SO lacunae, whereas relationships between osteocyte lacunar volume versus growth rate and basal metabolic rate disappeared. The relationship between osteocyte lacuna volume and genome size remained significant and moderately strong when measuring SO lacunae, whereas osteocyte lacuna volume was still unrelated to erythrocyte size. Our results indicate that growth and metabolic rate signals are contained in avian DO but not SO osteocyte lacunae, suggesting that the former should be used in estimating these parameters in extinct animals.

scholarly journals The efficiency of food utilization, digestibility of foodstuffs and energy expenditure of mice selected for large or small body size

1962 ◽  
Vol 3 (1) ◽  
pp. 51-68 ◽  
Author(s):  
Ruth E. Fowler
Keyword(s):  
Growth Rate ◽  
Body Size ◽  
Energy Expenditure ◽  
Small Body ◽  
Energetic Efficiency ◽  
Food Utilization ◽  
Control Line ◽  
Small Body Size ◽  
Gross Efficiency ◽  
Body Activity

The efficiency of food utilization, the digestibility of foodstuffs, energy metabolism, and body activity have been studied in three lines of mice, one selected for large, another for small body size, and a third, control, line.The gross efficiency of food utilization was highest in the large line, intermediate in the control line and lowest in the small line between 21 and approximately 35 days of age. During this period, gross efficiency declined in the large and control lines with increasing size and decreasing growth-rate, presumably due to an increase in maintenance costs in comparison with the weight gained. In the small line, the efficiency of food utilization increased up to 35 days of age but declined thereafter. The energetic efficiency (measured in Calories) was higher in the large than in the small line up to 4 weeks of age, i.e. when the growth-rate was high, and after 6 weeks of age, when fat was being deposited at an increased rate.The increased efficiency of large mice was not entirely associated with a greater proportion of the ingested food being absorbed from the gut. Large mice absorbed a greater proportion of protein, though the difference was not sufficient to account for the large weight difference between the large and small lines.The energy expenditure of mice of the large line was greater than that of the small line at all ages and similar for the same body weights. The reduced growth-rate of small mice was not due to abnormally high or low energy costs. There was no evidence that body activity determined or restricted the rate of growth in either line.Mice selected for small size were phenotypically unlike pituitary dwarf mice, although the low nitrogen retention during the growing-period indicated a deficiency of some growth stimulus.

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