scholarly journals Snow Buntings Maintain Winter-Level Cold Endurance While Migrating to the High Arctic

2021 ◽  
Vol 9 ◽  
Author(s):  
Audrey Le Pogam ◽  
Ryan S. O’Connor ◽  
Oliver P. Love ◽  
Justine Drolet ◽  
Lyette Régimbald ◽  
...  
Keyword(s):  
Body Mass ◽  
Empirical Studies ◽  
Muscle Thickness ◽  
Muscle Size ◽  
The Arctic ◽  
Pectoralis Muscle ◽  
Wintering Grounds ◽  
Fat Stores ◽  
Metabolic Performance ◽  
Thermogenic Capacity

Arctic breeding songbirds migrate early in the spring and can face winter environments requiring cold endurance throughout their journey. One such species, the snow bunting (Plectrophenax nivalis), is known for its significant thermogenic capacity. Empirical studies suggest that buntings can indeed maintain winter cold acclimatization into the migratory and breeding phenotypes when kept captive on their wintering grounds. This capacity could be advantageous not only for migrating in a cold environment, but also for facing unpredictable Arctic weather on arrival and during preparation for breeding. However, migration also typically leads to declines in the sizes of several body components linked to metabolic performance. As such, buntings could also experience some loss of cold endurance as they migrate. Here, we aimed to determine whether free-living snow buntings maintain a cold acclimatized phenotype during spring migration. Using a multi-year dataset, we compared body composition (body mass, fat stores, and pectoralis muscle thickness), oxygen carrying capacity (hematocrit) and metabolic performance (thermogenic capacity – Msum and maintenance energy expenditure – BMR) of birds captured on their wintering grounds (January–February, Rimouski, QC, 48°N) and during pre-breeding (April–May) in the Arctic (Alert, NU, 82°). Our results show that body mass, fat stores and Msum were similar between the two stages, while hematocrit and pectoralis muscle thickness were lower in pre-breeding birds than in wintering individuals. These results suggest that although tissue degradation during migration may affect flight muscle size, buntings are able to maintain cold endurance (i.e., Msum) up to their Arctic breeding grounds. However, BMR was higher during pre-breeding than during winter, suggesting higher maintenance costs in the Arctic.

scholarly journals Thermogenic side effects to migratory predisposition in shorebirds

2007 ◽  
Vol 292 (3) ◽  
pp. R1287-R1297 ◽  
Author(s):  
François Vézina ◽  
Kirsten M. Jalvingh ◽  
Anne Dekinga ◽  
Theunis Piersma
Keyword(s):  
Side Effects ◽  
Metabolic Rate ◽  
Body Mass ◽  
Muscle Hypertrophy ◽  
Significant Proportion ◽  
Pectoral Muscle ◽  
Thermal Acclimation ◽  
Muscle Size ◽  
Long Distance ◽  
Thermogenic Capacity

In the calidrine sandpiper red knot ( Calidris canutus), the weeks preceding takeoff for long-distance migration are characterized by a rapid increase in body mass, largely made up of fat but also including a significant proportion of lean tissue. Before takeoff, the pectoral muscles are known to hypertrophy in preparation for endurance flight without any specific training. Because birds facing cold environments counterbalance heat loss through shivering thermogenesis, and since pectoral muscles represent a large proportion of avian body mass, we asked the question whether muscle hypertrophy in preparation for long-distance endurance flight would induce improvements in thermogenic capacity. We acclimated red knots to different controlled thermal environments: 26°C, 5°C, and variable conditions tracking outdoor temperatures. We then studied within-individual variations in body mass, pectoral muscle size (measured by ultrasound), and metabolic parameters [basal metabolic rate (BMR) and summit metabolic rate (Msum)] throughout a 3-mo period enclosing the migratory gain and loss of mass. The gain in body mass during the fattening period was associated with increases in pectoral muscle thickness and thermogenic capacity independent of thermal acclimation. Regardless of their thermal treatment, birds showing the largest increases in body mass also exhibited the largest increases in Msum. We conclude that migratory fattening is accompanied by thermoregulatory side effects. The gain of body mass and muscle hypertrophy improve thermogenic capacity independent of thermal acclimation in this species. Whether this represents an ecological advantage depends on the ambient temperature at the time of fattening.

scholarly journals Avian pectoral muscle size rapidly tracks body mass changes during flight, fasting and fuelling

2000 ◽  
Vol 203 (5) ◽  
pp. 913-919 ◽  
Author(s):  
A. Lindstrom ◽  
A. Kvist ◽  
T. Piersma ◽  
A. Dekinga ◽  
M.W. Dietz
Keyword(s):  
Muscle Mass ◽  
Body Mass ◽  
Muscle Thickness ◽  
Pectoral Muscle ◽  
The Body ◽  
Muscle Size ◽  
Migratory Flight ◽  
Avian Muscle ◽  
Require Power ◽  
Body Mass Changes

We used ultrasonic imaging to monitor short-term changes in the pectoral muscle size of captive red knots Calidris canutus. Pectoral muscle thickness changed rapidly and consistently in parallel with body mass changes caused by flight, fasting and fuelling. Four knots flew repeatedly for 10 h periods in a wind tunnel. Over this period, pectoral muscle thickness decreased in parallel with the decrease in body mass. The change in pectoral muscle thickness during flight was indistinguishable from that during periods of natural and experimental fasting and fuelling. The body-mass-related variation in pectoral muscle thickness between and within individuals was not related to the amount of flight, indicating that changes in avian muscle do not require power-training as in mammals. Our study suggests that it is possible for birds to consume and replace their flight muscles on a time scale short enough to allow these muscles to be used as part of the energy supply for migratory flight. The adaptive significance of the changes in pectoral muscle mass cannot be explained by reproductive needs since our knots were in the early winter phase of their annual cycle. Instead, pectoral muscle mass changes may reflect (i) the breakdown of protein during heavy exercise and its subsequent restoration, (ii) the regulation of flight capacity to maintain optimal flight performance when body mass varies, or (iii) the need for a particular protein:fat ratio in winter survival stores.

scholarly journals Orbicularis Oculi Muscle Size and Function: Exploring the Influence of Aging and Exercise Training

Cosmetics ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 29
Author(s):  
Takashi Abe ◽  
Jeremy P. Loenneke
Keyword(s):  
Older Adults ◽  
Exercise Training ◽  
Muscle Hypertrophy ◽  
Peak Velocity ◽  
Muscle Thickness ◽  
Muscle Size ◽  
Sphincter Muscle ◽  
Orbicularis Oculi Muscle ◽  
Orbicularis Oculi ◽  
And Function

The orbicularis oculi muscle is the sphincter muscle of the eyelids that blinks and closes the eyes. In this review, our aim was threefold: (1) to introduce the performance characteristics of blinking activity in young and older adults, (2) to discuss the influence of aging on the orbicularis oculi muscle in healthy adults, and (3) to provide information about the effect of facial exercise training on the orbicularis oculi muscle. To achieve the purpose of this review, a search using two electronic databases (PubMed and Scopus) and a search engine (Google Scholar) was conducted. The amplitude and peak velocity of spontaneously blinking behavior, which is an index of muscle function of the orbicularis oculi, appear to be affected by aging. The muscle thickness of the orbicularis oculi tends to be low in older adults, but there are issues that need to be examined further, such as differences in sex and measurement positions. There was no study on the effect of exercise training; however, the results of a highly trained man indicate that the orbicularis oculi muscles might elicit muscle hypertrophy through non-traditional resistance exercise.

scholarly journals Efficacy of phosphatidic acid ingestion on lean body mass, muscle thickness and strength gains in resistance-trained men

2012 ◽  
Vol 9 (1) ◽  
Author(s):  
Jay R Hoffman ◽  
Jeffrey R Stout ◽  
David R Williams ◽  
Adam J Wells ◽  
Maren S Fragala ◽  
...  
Keyword(s):  
Phosphatidic Acid ◽  
Lean Body Mass ◽  
Body Mass ◽  
Muscle Thickness

Pharmacological Inhibition of Myostatin and Changes in Lean Body Mass and Lower Extremity Muscle Size in Patients Receiving Androgen Deprivation Therapy for Prostate Cancer

2014 ◽  
Vol 99 (10) ◽  
pp. E1967-E1975 ◽  
Author(s):  
Desmond Padhi ◽  
Celestia S. Higano ◽  
Neal D. Shore ◽  
Paul Sieber ◽  
Erik Rasmussen ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Lean Body Mass ◽  
Body Mass ◽  
Phase 1 ◽  
Muscle Growth ◽  
Androgen Deprivation ◽  
Negative Regulator ◽  
Muscle Size ◽  
Muscle Loss ◽  
Lower Extremity Muscle

Abstract Context: Myostatin is a negative regulator of muscle growth. Androgen deprivation (ADT) is associated with muscle loss and increased body fat, and currently available therapies have limited efficacy to treat this complication. The antimyostatin peptibody (AMG 745/Mu-S) markedly attenuated muscle loss and decreased fat accumulation in orchiectomized mice. Objective: The objective of the study was to evaluate the safety, pharmacokinetics, and muscle efficacy of AMG 745 in men undergoing ADT for nonmetastatic prostate cancer. Methods: This was a randomized, blinded, placebo-controlled, multiple-dose, phase 1 study of AMG 745 given for 28 days. The end point of percentage change from baseline in lean body mass (LBM) as assessed by dual x-ray absorptiometry was prespecified. Results: Rates of adverse events (AMG 745 vs placebo) were the following: diarrhea (13% vs 9%), fatigue (13% vs 4%), contusion (10% vs 0%), and injection site bruising (6% vs 4%). Exposure increased linearly from 0.3 mg/kg to 3 mg/kg. AMG 745 significantly increased LBM in the 3 mg/kg vs the placebo groups on day 29 by 2.2% (±0.8% SE, P = 0.008); in exploratory fat mass analysis, a decrease of −2.5% (±1.0% SE, P = 0.021) was observed. Pharmacodynamic changes in muscle and fat were maintained at follow-up, 1 month after day 29. Conclusion: Four weekly sc doses of AMG 745 were well tolerated and were associated with increased LBM and decreased fat in the men receiving ADT for nonmetastatic prostate cancer. Results support further investigation of AMG 745 in clinical settings with muscle loss and atrophy.

Lack of variation in nuclear DNA content in avian muscle

Genome ◽  
2021 ◽  
pp. 1-9
Author(s):  
Ana Gabriela Jimenez ◽  
Emily Gray Lencyk
Keyword(s):  
Dna Content ◽  
Nuclear Dna ◽  
Nuclear Dna Content ◽  
Muscle Size ◽  
Pectoralis Muscle ◽  
Long Distance ◽  
Cross Sectional ◽  
Avian Muscle ◽  
Myonuclear Domain ◽  
Temperate Birds

The avian pectoralis muscle demonstrates plasticity with regard to size, so that temperate birds facing winter conditions or birds enduring a migration bout tend to have significant increases in the size and mass of this tissue due to muscular hypertrophy. Myonuclear domain (MND), the volume of cytoplasm a myonuclei services, in the pectoralis muscle of birds seems to be altered during thermal stress or changing seasons. However, there is no information available regarding muscle DNA content or ploidy level within the avian pectoralis. Changes in muscle DNA content can be used in this tissue to aid in size and mass changes. Here, we hypothesized that long-distance migrants or temperate residents would use the process of endoreduplication to aid in altering muscle size. Mostly contradictory to our hypotheses, we found no differences in the mean muscle DNA content in any of the 62 species of birds examined in this study. We also found no correlations between mean muscle DNA content and other muscle structural measurements, such as the number of nuclei per millimeter of fiber, myonuclear domain, and fiber cross-sectional area. Thus, while avian muscle seems more phenotypically plastic than mammalian muscle, the biological processes surrounding myonuclear function may be more closely related to those seen in mammals.

scholarly journals Multiple Functional Solutions During Flightless to Flight-Capable Transitions

2021 ◽  
Vol 8 ◽  
Author(s):  
Ashley M. Heers ◽  
Stephanie L. Varghese ◽  
Leila K. Hatier ◽  
Jeremiah J. Cabrera
Keyword(s):  
Empirical Studies ◽  
Three Dimensional ◽  
Muscle Size ◽  
Whole Body ◽  
Ontogenetic Changes ◽  
Skeletal Morphology ◽  
Avian Flight ◽  
And Performance ◽  
Locomotor Behaviors ◽  
And Behavior

The evolution of avian flight is one of the great transformations in vertebrate history, marked by striking anatomical changes that presumably help meet the demands of aerial locomotion. These changes did not occur simultaneously, and are challenging to decipher. Although extinct theropods are most often compared to adult birds, studies show that developing birds can uniquely address certain challenges and provide powerful insights into the evolution of avian flight: unlike adults, immature birds have rudimentary, somewhat “dinosaur-like” flight apparatuses and can reveal relationships between form, function, performance, and behavior during flightless to flight-capable transitions. Here, we focus on the musculoskeletal apparatus and use CT scans coupled with a three-dimensional musculoskeletal modeling approach to analyze how ontogenetic changes in skeletal anatomy influence muscle size, leverage, orientation, and corresponding function during the development of flight in a precocial ground bird (Alectoris chukar). Our results demonstrate that immature and adult birds use different functional solutions to execute similar locomotor behaviors: in spite of dramatic changes in skeletal morphology, muscle paths and subsequent functions are largely maintained through ontogeny, because shifts in one bone are offset by changes in others. These findings help provide a viable mechanism for how extinct winged theropods with rudimentary pectoral skeletons might have achieved bird-like behaviors before acquiring fully bird-like anatomies. These findings also emphasize the importance of a holistic, whole-body perspective, and the need for extant validation of extinct behaviors and performance. As empirical studies on locomotor ontogeny accumulate, it is becoming apparent that traditional, isolated interpretations of skeletal anatomy mask the reality that integrated whole systems function in frequently unexpected yet effective ways. Collaborative and integrative efforts that address this challenge will surely strengthen our exploration of life and its evolutionary history.

scholarly journals High Basal Metabolic Rates of Shorebirds While in the Arctic: A Circumpolar View

The Condor ◽  
2003 ◽  
Vol 105 (3) ◽  
pp. 420-427 ◽  
Author(s):  
Åke Lindström ◽  
Marcel Klaassen
Keyword(s):  
Body Mass ◽  
Canadian Arctic ◽  
Mass Range ◽  
The Arctic ◽  
Data Sets ◽  
Migration Route ◽  
Long Distance ◽  
Ambient Temperatures ◽  
Physiological Adaptations ◽  
Southward Migration

Abstract The basal metabolic rate (BMR) of Old World long-distance-migrant shorebirds has been found to vary along their migration route. On average, BMR is highest in the Arctic at the start of fall migration, intermediate at temperate latitudes, and lowest on the tropical wintering grounds. As a test of the generality of this pattern, we measured the BMR of one adult and 44 juvenile shorebirds of 10 species (1–18 individuals of each species, body-mass range 19–94 g) during the first part of their southward migration in the Canadian Arctic (68–76°N). The interspecific relationship between BMR and body mass was almost identical to that found for juvenile shorebirds in the Eurasian Arctic (5 species), although only one species appeared in both data sets. We conclude that high BMR of shorebirds in the Arctic is a circumpolar phenomenon. The most likely explanation is that the high BMR reflects physiological adaptations to low ambient temperatures. Whether the BMR of New World shorebirds drops during southward migration remains to be investigated. Altas Tasas Metabólicas Basales de Aves Playeras Mientras Se Encuentran en el Ártico: Una Visión Circumpolar Resumen. Se ha encontrado que la tasa metabólica basal (TMB) de las aves playeras migratorias de larga distancia varía a lo largo de sus rutas de migración en el viejo mundo. En promedio, la TMB es máxima al comienzo de la migración otoñal en el ártico, intermedia en latitudes templadas y mínima en las áreas tropicales de invernada. Para poner a prueba la generalidad de este patrón, medimos la TMB de un individuo adulto y 44 juveniles de diez especies de aves playeras (1–18 individuos de cada especie, rango de peso corporal 19–94 g) durante la primera parte de su migración hacia el sur en el ártico canadiense (68–76°N). La relación interespecífica entre la TMB y el peso corporal fue casi idéntica a la que se había encontrado en juveniles de 5 especies de aves playeras en el ártico de Eurasia, aunque sólo una especie fue considerada en ambos estudios. Concluimos que la alta TMB de las aves playeras en el ártico representa un fenómeno circumpolar. La explicación más probable es que las altas TMBs reflejan adaptaciones fisiológicas a ambientes de bajas temperaturas. Aún no se ha investigado si las TMBs de las aves playeras del nuevo mundo disminuyen durante la migración hacia el sur.

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