scholarly journals Fasting in the ureotelic Lake Magadi tilapia, Alcolapia grahami, does not reduce its high metabolic demand, increasing its vulnerability to siltation events

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Gudrun De Boeck ◽  
Chris M Wood ◽  
Kevin V Brix ◽  
Amit K Sinha ◽  
Victoria Matey ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Rate ◽  
Food Source ◽  
Swimming Performance ◽  
Aerobic Performance ◽  
Metabolic Rates ◽  
Term Survival ◽  
Ammonia Metabolism ◽  
Lake Magadi ◽  
Alcolapia Grahami

Abstract Lake Magadi, Kenya, is one of the most extreme aquatic environments on Earth (pH~10, anoxic to hyperoxic, high temperatures). Recently, increased water demand and siltation have threatened the viable hot springs near the margins of the lake where Alcolapia grahami, the only fish surviving in the lake, live. These Lake Magadi tilapia largely depend on nitrogen-rich cyanobacteria for food and are 100% ureotelic. Their exceptionally high aerobic metabolic rate, together with their emaciated appearance, suggests that they are energy-limited. Therefore, we hypothesized that during food deprivation, Magadi tilapia would economize their energy expenditure and reduce metabolic rate, aerobic performance and urea-N excretion. Surprisingly, during a 5-day fasting period, routine metabolic rates increased and swimming performance (critical swimming speed) was not affected. Urea-N excretion remained stable despite the lack of their N-rich food source. Their nitrogen use switched to endogenous sources as liver and muscle protein levels decreased after a 5-day fast, indicating proteolysis. Additionally, fish relied on carbohydrates with lowered muscle glycogen levels, but there were no signs indicating use of lipid stores. Gene expression of gill and gut urea transporters were transiently reduced as were gill rhesus glycoprotein Rhbg and Rhcg-2. The reduction in gill glutamine synthetase expression concomitant with the reduction in Rh glycoprotein gene expression indicates reduced nitrogen/ammonia metabolism, most likely decreased protein synthesis. Additionally, fish showed reduced plasma total CO2, osmolality and Na+ (but not Cl−) levels, possibly related to reduced drinking rates and metabolic acidosis. Our work shows that Lake Magadi tilapia have the capacity to survive short periods of starvation which could occur when siltation linked to flash floods covers their main food source, but their seemingly hardwired high metabolic rates would compromise long-term survival.

Metabolic Rate and Energy Expenditure of the Spiny Dogfish, Squalus acanthias

1978 ◽  
Vol 35 (6) ◽  
pp. 816-821 ◽  
Author(s):  
J. R. Brett ◽  
J. M. Blackburn
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Key Words ◽  
Swimming Performance ◽  
Squalus Acanthias ◽  
Spiny Dogfish ◽  
Metabolic Rates ◽  
Performance Curve ◽  
Power Performance ◽  
General Energy

The metabolic rate of spiny dogfish, Squalus acanthias, was determined in both a tunnel respirometer and a large, covered, circular tank (mass respirometer). Swimming performance was very poor in the respirometer, so that a power–performance curve could not be established. Instead, resting metabolic rates were determined, with higher rates induced by causing heavy thrashing (active metabolism). Routine metabolic rates were measured for the spontaneous activity characterizing behavior in the circular tank. For fish of 2 kg mean weight, the metabolic rates at 10 °C were 32.4 ± 2.6 SE (resting), 49.2 ± 5.0 SE (routine), and 88.4 ± 4.6 SE (active) mg O2∙kg−1∙h−1. Assuming that the routine rate represents a general energy expenditure in nature, this is equivalent to metabolizing about 3.8 kcal∙kg−1∙d−1 (15.9 × 103 J∙kg−1∙d−1). Key words: dogfish, metabolic rates, energetics, respiration

scholarly journals Reproductive energetics of adult male yellow-bellied marmots (Marmota flaviventris)

1995 ◽  
Vol 73 (10) ◽  
pp. 1791-1797 ◽  
Author(s):  
Carmen M. Salsbury ◽  
Kenneth B. Armitage
Keyword(s):  
Energy Expenditure ◽  
Metabolic Rate ◽  
Adult Male ◽  
Reproductive Investment ◽  
High Energy ◽  
Male Reproductive Success ◽  
Metabolic Rates ◽  
Marmota Flaviventris ◽  
Term Survival ◽  
Active Season

We examined the energy expenditure of adult male yellow-bellied marmots (Marmota flaviventris) and its relationship to various female-defense characteristics critical to male reproductive success. Resting metabolic rates of males were estimated in the laboratory via oxygen-consumption analysis, and field metabolic rates were estimated using a doubly labeled water technique. Male home-range size, number of females defended by males, dispersion of females in the habitat, and date into the active season were considered to be predictors of male energy expenditure in excess of maintenance costs (field metabolic rate minus resting metabolic rate). Energy expenditure was best explained by a defensibility index based on the number and dispersion of females defended; expenditure increased with number and dispersion of females. Energy expenditure increased with date into the active season. Environmental constraints on male activity during the mating season may have led to a shift in male reproductive investment to later in the season, when intruder pressure by conspecifics increased. No short-term survival costs were associated with high energy expenditure; males appeared to engage in reproductive behaviors congruent with their physiological capabilities.

scholarly journals Metabolic traits in brown trout (Salmo trutta) vary in response to food restriction and intrinsic factors

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Louise C Archer ◽  
Stephen A Hutton ◽  
Luke Harman ◽  
W Russell Poole ◽  
Patrick Gargan ◽  
...  
Keyword(s):  
Life History ◽  
Metabolic Rate ◽  
Intraspecific Variation ◽  
Brown Trout ◽  
Environmental Conditions ◽  
Food Restriction ◽  
Metabolic Rates ◽  
Intrinsic Factors ◽  
Metabolic Traits ◽  
Food Conditions

Abstract Metabolic rates vary hugely within and between populations, yet we know relatively little about factors causing intraspecific variation. Since metabolic rate determines the energetic cost of life, uncovering these sources of variation is important to understand and forecast responses to environmental change. Moreover, few studies have examined factors causing intraspecific variation in metabolic flexibility. We explore how extrinsic environmental conditions and intrinsic factors contribute to variation in metabolic traits in brown trout, an iconic and polymorphic species that is threatened across much of its native range. We measured metabolic traits in offspring from two wild populations that naturally show life-history variation in migratory tactics (one anadromous, i.e. sea-migratory, one non-anadromous) that we reared under either optimal food or experimental conditions of long-term food restriction (lasting between 7 and 17 months). Both populations showed decreased standard metabolic rates (SMR—baseline energy requirements) under low food conditions. The anadromous population had higher maximum metabolic rate (MMR) than the non-anadromous population, and marginally higher SMR. The MMR difference was greater than SMR and consequently aerobic scope (AS) was higher in the anadromous population. MMR and AS were both higher in males than females. The anadromous population also had higher AS under low food compared to optimal food conditions, consistent with population-specific effects of food restriction on AS. Our results suggest different components of metabolic rate can vary in their response to environmental conditions, and according to intrinsic (population-background/sex) effects. Populations might further differ in their flexibility of metabolic traits, potentially due to intrinsic factors related to life history (e.g. migratory tactics). More comparisons of populations/individuals with divergent life histories will help to reveal this. Overall, our study suggests that incorporating an understanding of metabolic trait variation and flexibility and linking this to life history and demography will improve our ability to conserve populations experiencing global change.

scholarly journals Psychological and Physiological Features Associated with Swimming Performance

2021 ◽  
Vol 18 (9) ◽  
pp. 4561
Author(s):  
Vicente Javier Clemente-Suárez ◽  
Juan Pedro Fuentes-García ◽  
Ricardo J. Fernandes ◽  
João Paulo Vilas-Boas
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Swimming Performance ◽  
Aerobic Performance ◽  
Anaerobic Performance ◽  
Probe Characteristic ◽  
Time Domains ◽  
High Fatigue ◽  
Psychological Features ◽  
Aerobic And Anaerobic

Background: The aim of the present research was to study the psychological and physiological features associated with aerobic and anaerobic performance in trained swimmers. Methods: A correlation and stepwise regression analyses were conducted with the data obtained in a RESTQ-76 sport questionnaire, a heart rate variability test, and an anaerobic and aerobic swimming performance efforts of 20 swimmers. Results: Aerobic performance correlated, principally, with parameters related to parasympathetic modulation measured in the frequency and time domains of the heart rate variability (LF/HF r: −0.806, p < 0.001; NN50 r: 0.937, p < 0.001). Swimmers’ anaerobic performance correlated to psychological features (low stress r: 0.526, p: 0.025, and high fatigue r: −0.506, p: 0.032). Conclusion: Swimming performance presented different psychological and physiological features depending on the probe characteristic. Specifically, swimmers’ anaerobic performance was associated with psychological features (low stress and high fatigue perception) and aerobic performance with physiological features (high parasympathetic modulation). This information could help coaches to know the variables to control in their swimmers, depending on the probe in which they compete (anaerobic or aerobic).

scholarly journals Whole blood gene expression within days after total-body irradiation predicts long term survival in Gottingen minipigs

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sunita Chopra ◽  
Maria Moroni ◽  
Jaleal Sanjak ◽  
Laurel MacMillan ◽  
Bernadette Hritzo ◽  
...  
Keyword(s):  
Gene Expression ◽  
Total Body Irradiation ◽  
Whole Blood ◽  
Radiation Effects ◽  
Expression Profiles ◽  
Mass Casualty ◽  
Machine Learning Algorithms ◽  
Term Survival ◽  
Blood Gene Expression ◽  
Total Body

AbstractGottingen minipigs mirror the physiological radiation response observed in humans and hence make an ideal candidate model for studying radiation biodosimetry for both limited-sized and mass casualty incidents. We examined the whole blood gene expression profiles starting one day after total-body irradiation with increasing doses of gamma-rays. The minipigs were monitored for up to 45 days or time to euthanasia necessitated by radiation effects. We successfully identified dose- and time-agnostic (over a 1–7 day period after radiation), survival-predictive gene expression signatures derived using machine-learning algorithms with high sensitivity and specificity. These survival-predictive signatures fare better than an optimally performing dose-differentiating signature or blood cellular profiles. These findings suggest that prediction of survival is a much more useful parameter for making triage, resource-utilization and treatment decisions in a resource-constrained environment compared to predictions of total dose received. It should hopefully be possible to build such classifiers for humans in the future.

Predictive value of gene expression profiling for long-term survival after heart transplantation

2017 ◽  
Vol 41 ◽  
pp. 27-31 ◽  
Author(s):  
Buntaro Fujita ◽  
Emir Prashovikj ◽  
Uwe Schulz ◽  
Jochen Börgermann ◽  
Jakub Sunavsky ◽  
...  
Keyword(s):  
Gene Expression ◽  
Heart Transplantation ◽  
Gene Expression Profiling ◽  
Predictive Value ◽  
Expression Profiling ◽  
Term Survival ◽  
Long Term Survival

scholarly journals Hypoxic culture conditions induce increased metabolic rate and collagen gene expression in ACL-derived cells

2015 ◽  
Vol 34 (6) ◽  
pp. 985-994 ◽  
Author(s):  
Tomasz J. Kowalski ◽  
Natalie L. Leong ◽  
Ayelet Dar ◽  
Ling Wu ◽  
Nima Kabir ◽  
...  
Keyword(s):  
Gene Expression ◽  
Metabolic Rate ◽  
Culture Conditions ◽  
Collagen Gene ◽  
Collagen Gene Expression
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