No description available.

No description available.

<p>Oxygen consumption and carbon dioxide production are usual measurements within the sports and training physiology. The same measurements are also common when it comes to establish the amount of energy that is used during work and to establish the intensity of work. The volume of oxygen that is consumed contra the volume of carbon dioxide that is produced can be used to calculate the metabolic rate within the human body. This calculation shows the percent relationship between carbohydrates and fat in the metabolism. </p><p>The first accurate method to measure the breathing gases for use in metabolic calculation was established in the early twenty century when the Douglas bag method was introduced. The expired air is collected in sealed bags and the volume of expired air is then analyzed when it comes to its content of oxygen and carbon dioxide. In our days several methods have been developed for automatic analysis of the breathing gases where the expired air is analyzed immediately by electronic instruments. </p><p>When it comes to the modern automatic instruments there are few scientific investigations about their reliability and that has raised questions about how accurate measurements they produce. One instrument is the Oxycon Stationary Pro which is used by Gymnastik- och Idrottshögskolan in Stockholm Sweden and several of the Swedish university hospital. In this report there has been done a practical comparison between the Douglas bag method and the automatic instrument Oxycon Stationary Pro. The comparison showed a great similarity when it come to the metabolic rate. When it comes to the respiratory gases however, the Oxycon Stationary Pro shows values up to five percent higher than the Douglas bag.</p>

Oxygen consumption and carbon dioxide production are usual measurements within the sports and training physiology. The same measurements are also common when it comes to establish the amount of energy that is used during work and to establish the intensity of work. The volume of oxygen that is consumed contra the volume of carbon dioxide that is produced can be used to calculate the metabolic rate within the human body. This calculation shows the percent relationship between carbohydrates and fat in the metabolism. The first accurate method to measure the breathing gases for use in metabolic calculation was established in the early twenty century when the Douglas bag method was introduced. The expired air is collected in sealed bags and the volume of expired air is then analyzed when it comes to its content of oxygen and carbon dioxide. In our days several methods have been developed for automatic analysis of the breathing gases where the expired air is analyzed immediately by electronic instruments. When it comes to the modern automatic instruments there are few scientific investigations about their reliability and that has raised questions about how accurate measurements they produce. One instrument is the Oxycon Stationary Pro which is used by Gymnastik- och Idrottshögskolan in Stockholm Sweden and several of the Swedish university hospital. In this report there has been done a practical comparison between the Douglas bag method and the automatic instrument Oxycon Stationary Pro. The comparison showed a great similarity when it come to the metabolic rate. When it comes to the respiratory gases however, the Oxycon Stationary Pro shows values up to five percent higher than the Douglas bag.

Body shape affects the capacity and efficiency of swimming in fishes, and places constraints on foraging and reproductive performance. Hence, fitness components, such as aerobic swimming capacity and efficiency, can be determined from analysis of swimming energetics using active respirometry. In particular, body shape adaptations, such as streamlining, aim at reducing hydrodynamic drag (resistance), thereby increasing swimming efficiency in the presence of water flow, which is a principal contributor to resistance for fish inhabiting rivers. For two populations of bluegill sunfish, one from the Brazos River and the other from Moelman’s Slough (a Brazos River oxbow lake), the metabolic transport rate (MTR) was determined to evaluate differences in swimming efficiency. The standard cost of swimming (SCOS) was also determined to evaluate differences in swimming capacity, which represents the overall capacity of the skeletal muscles to generate mechanical power to overcome hydrodynamic resistance. The MTR and the SCOS describe holistic swimming performance, where the MTR specifies the hydrodynamic response due to swimming, and the SCOS specifies the physiologic response due to swimming. The differences in swimming performance are mainly attributed to factors affecting hydrodynamic resistance and could be predicted by morphology; because body shape, like water flow, is also a principal contributor to resistance. Multivariate body shape, from generalized Procrustes analysis, was used to assess the influence of multiple shape traits on swimming costs. This measure of shape related to swimming performance using partial least-squares analysis showed the two bluegill populations to be significantly different. The results were as follows: the shallow-bodied condition in bluegills was highly correlated with efficient swimming and low swimming capacities; whereas, deep-bodied bluegills were highly correlated with inefficient swimming and high swimming capacities. This is an empirical case of divergent natural selection. For convergence, however, the position of the caudal peduncle is consistent with optimal swimming speed (Um), which depends on standard metabolic rate (SMR), or metabolic maintenance. Bluegills with erect caudal peduncles have a high range of swimming speeds without suffering much cost of swimming ability compared to bluegills with prone caudal peduncles. The adaptive physiological response to high Um is due to a low SCOS because swimming efficiency is low and metabolic maintenance is high. In other words, bluegills that are inefficient swimmers and require a high energy intake cannot survive unless they gain the ability to increase their foraging capacity by thrust or metabolic power reduction. This is perhaps one of the most remarkable adaptive physiological responses due to the joint effects of shape and SMR.

No description available.

Many studies have reported individual differences in resting metabolic rate (RMR), the energetic cost of self-maintenance. Differences among individuals in the energetic cost of self-maintenance may influence life-history decisions and hence, fitness. In this study, we examined potential causes of intra-specific variation in RMR in zebrafish, Danio rerio. First, the repeatability of RMR was determined to check whether a single measure was reflective of future physiological performance. As predicted, RMR was repeatable over a period of three weeks. However, none of stress-coping style, baseline cortisol levels, metabolically-active organ (gill, heart, intestine and liver) mass, aggression or activity levels were correlated with RMR, i.e. none of these factors were significant contributors to individual variation in RMR. These results imply that other factors must be sought to explain the inter-individual variation in RMR observed in zebrafish.

Basal metabolic rate (BMR), the sum of maintenance energy costs, represents a major component of the energy budgets of ectothermic vertebrates and varies between individuals within a species. Individual ectotherms are generally assumed to have a constant BMR at any given temperature. A strategy of flexibility in BMR might have evolved to cope with differing environmental conditions. Within-individual variation in BMR was examined in two fishes, juvenile Atlantic salmon Salmo salar and juvenile northern pike Esox lucius, whilst the effects of exercise and ration on BMR, maximum metabolic rate (MMR), enzyme levels and body composition were studied in detail for pike. In the first part of the study, measurements of BMR were made for first-summer Atlantic salmon parr at rest by respirometry. In 1996, initial measurements of BMR were made for 25 fish held in a stock tank. Fish were then allocated in small groups to channels to represent a change in environment and BMR re-measured after a period of several weeks. The procedure was repeated for 30 fish in the summer of 1997, when fish were given a reduced food ration. Variation in BMR in each experiment was analysed for individual fish, and for all fish using a linear mixed model. There were statistically significant differences in BMR values between the two times, the within-individual, between-time variation representing approximately ± 21% of BMR in 1996 and ± 28% of BMR in 1997. Reduced-rafion fish (1997) displayed a significant decrease in the mean elevation of the allometric scaling relationship between body mass and BMR between time periods. To further explore possible mechanisms for flexibility in BMR and relationships with MMR, juvenile pike were used. Initial measurements of BMR and MMR (following exhaustive exercise) were made and factorial metabolic scope calculated (MMR/BMR). Fish were then split into a high ration no-exercise group (n = 10), low ration no-exercise group (n = 10) and sustained exercise group (n = 13). Initial measurements were termed time 1, with subsequent measurements made after approximately 3 weeks (time 2) and 11 weeks (time 3). Exercised fish had a significantly larger MMR and scope following 3 weeks of sustained swimming. For all fish there were significant correlations between BMR and MMR at times 1 and 3 but not at time 2.After the oxygen measurements made at time 3 all fish were humanely killed. Maximal enzyme assays were performed on six tissues for each remaining fish (n = 30). Levels of each of two enzymes (citrate synthase, CS, and lactate dehydrogenase, LDH, measured in the direction of lactate oxidation) were found to be similar between treatment groups for respective tissues. Total CS activity levels and LDH levels were highest in the heart and red muscle. In general there was little difference in the relative organ masses of fish exposed to different treatments. It is concluded that in these two fish species with very different life styles, between- and within- individual variation in BMR (salmon & pike) and MMR (pike only) is apparent and that differences in ration and exercise influence individual physiology.

Resting metabolic rate (RMR) is the minimum energy expenditure necessary for survival. RMR varies widely both among and within species and a central question in evolutionary physiology concerns the functional basis for this variation. Juvenile North American red squirrels were used to investigate fitness consequences of variation in RMR by considering how expenditure relates to differences in food availability and to overwinter survival. Additionally, this thesis examines whether red squirrels exhibit phenotypic plasticity in RMR in response to varying levels of food availability. Results indicate that heavier juveniles with relatively low RMRs were more likely to survive overwinter. Moreover, these juveniles were capable of allocating more energy towards mechanical work and possessed larger food stores. Food supplemented yearlings exhibited higher RMRs than unsupplemented controls at the onset of the breeding season, while no difference in RMR was detected following termination of supplementation. / Wildlife Ecology

Many studies have reported individual differences in resting metabolic rate (RMR), the energetic cost of self-maintenance. Differences among individuals in the energetic cost of self-maintenance may influence life-history decisions and hence, fitness. In this study, we examined potential causes of intra-specific variation in RMR in zebrafish, Danio rerio. First, the repeatability of RMR was determined to check whether a single measure was reflective of future physiological performance. As predicted, RMR was repeatable over a period of three weeks. However, none of stress-coping style, baseline cortisol levels, metabolically-active organ (gill, heart, intestine and liver) mass, aggression or activity levels were correlated with RMR, i.e. none of these factors were significant contributors to individual variation in RMR. These results imply that other factors must be sought to explain the inter-individual variation in RMR observed in zebrafish.