Nutritional ecology of the ascidian Pyura stolonifera: influence of body size, food quantity and quality on filter-feeding, respiration, assimilation efficiency and energy balance

The absorptance to solar radiation, integrated across a wide range of wavelengths, was measured for selected species of Australian lizards. Some, but not all, agamids demonstrated the ability to change absorptance. None of the varanid lizards measured changed absorptance, including Varanus storri, which had been reported to change colour. An energy balance model was used to explore the effects of absorptance, changes in absorptance, and body size in varanid lizards, the dragon Ctenophorus caudicinctus (which changed absorptance from 77.0 to 87.7%) and the frillneck lizard (Chlamydosaurus kingii). Although higher absorptance values generally result in higher body temperatures, the effect of body size is great and must be taken into account in comparisons. Although some species with high absorptances are associated with relatively cool climates (Varanus rosenbergi) or with a semi-aquatic lifestyle (V. mertensi), the absorptances of other species are not as easily explained [such as the high absorptances of the tropical terrestrial V. panoptes (87%) and the tropical arboreal V. scalaris (86%)]. The absorptances of more species are required before the importance of climate and phylogenetic relationships can be fully evaluated. To facilitate future measurements, the apparatus used in this study is described in detail.

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ACTIVITY, CALORIE INTAKE, FAT STORAGE, AND THE ENERGY BALANCE OF INFANTS

PEDIATRICS ◽

10.1542/peds.41.1.18 ◽

1968 ◽

Vol 41 (1) ◽

pp. 18-29

Author(s):

Hedwig E. Rose ◽

Jean Mayer

Keyword(s):

Body Size ◽

Energy Balance ◽

Body Mass ◽

Environmental Conditions ◽

Calorie Intake ◽

Mitochondrial Activity ◽

Fat Storage ◽

Average Individual

Activity has long been known to be a major factor in the energy balance of moving organisms. Recently, the relative inactivity of obese individuals and the hyperactivity of thin individuals have received much attention. A study of the relationships of activity, growth, fat storage, and calorie intake of 31 infants living under normal home environmental conditions suggests that the unusually fat and the unusually thin infant may have, respectively, a smaller and larger number of active cells and, therefore, lower and higher BMR's per unit of body mass than the average individual. This would seem to confirm the theory that BMR is a function of inherent mitochondrial activity rather than of body size or shape.

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Energy balance in rats given chronic hormone treatment

British Journal Of Nutrition ◽

10.1079/bjn19890134 ◽

1989 ◽

Vol 61 (3) ◽

pp. 445-452 ◽

Cited By ~ 14

Author(s):

Christopher J. H. Woodward ◽

Peter W. Emery

Keyword(s):

Growth Rate ◽

Body Weight ◽

Body Size ◽

Energy Balance ◽

Hormone Treatment ◽

High Energy ◽

Fat Free Mass ◽

Sprague Dawley ◽

The Difference ◽

And Control

1. Sprague–Dawley rats were given corticosterone for 4 to 14 d either by subcutaneous injection (50 mg/kg body-weight per d) or as a higher dose in the diet (1 g/kg diet). Energy balance was calculated using the comparative carcass technique.2. Corticosterone significantly suppressed growth rate by at least 50% (P < 0·001 in all experiments). The reduction in growth was more marked in males than in females.3. Hormone treatment significantly reduced metabolizable intake (kJ/d) in males but not in females. Expressed relative to either metabolic body size (kg body-weight0·75) or fat-free mass, metabolizable intake tended to be increased in the treated groups.4. Energy expenditure, calculated as the difference between metabolizable intake and gain and expressed as kJ/d, did not differ between treated and control rats. Relative to either metabolic body size or fat-free mass, expenditure was consistently increased in treated rats. This change was statistically significant in five of the eight comparisons.5. The corticosterone-treated rat is characterized by high energy intake and expenditure relative to its body size and growth rate. Alterations in the relative sizes of different lean tissues may contribute to these changes.

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Temperature Acclimation of Mytilus Edulis With Reference to its Energy Budget

Journal of the Marine Biological Association of the United Kingdom ◽

10.1017/s0025315400018002 ◽

1971 ◽

Vol 51 (4) ◽

pp. 827-843 ◽

Cited By ~ 205

Author(s):

J. Widdows ◽

B. L. Bayne

Keyword(s):

Oxygen Consumption ◽

Energy Balance ◽

Cold Acclimation ◽

Mytilus Edulis ◽

Energy Budget ◽

Filtration Rate ◽

Physiological Stress ◽

Assimilation Efficiency ◽

Experimental Period ◽

Temperature Acclimation

Mytilus edulis L. is shown to acclimate to high and low temperature under laboratory conditions. The warm and cold acclimation of oxygen consumption, filtration rate and assimilation efficiency are described for groups of animals maintained at three food-cell concentrations. Complete acclimation (Precht's type 2) of oxygen consumption and filtration rate occur within 14 days. There is no change in assimilation efficiency within the 28-day experimental period. The results are integrated and discussed in the context of a simple energy budget. In terms of the energy budget there exists a marked contrast between warm and cold acclimation. An “index of energy balance” is proposed in order to assess the state of the energy balance. When animals are fed above the maintenance requirement the energy budget remains in an equilibrium state during cold acclimation, whereas the acclimation to a warm temperature regime disrupts the balance and represents a physiological stress. During warm acclimation, prior to the re-establishment of an energy equilibrium the blood sugar level increases, suggesting that the animal is required to mobilize and utilize its energy reserves.

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