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Claude Duchamp - One of the best experts on this subject based on the ideXlab platform.
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Transcriptomic data analysis and differential gene expression of antioxidant pathways in king penguin juveniles (Aptenodytes Patagonicus) before and after acclimatization to marine life.
Data in brief, 2016Co-Authors: Benjamin Rey, Cyril Degletagne, Claude DuchampAbstract:Abstract In this article, we present differentially expressed gene profiles in the pectoralis muscle of wild juvenile king penguins that were either naturally acclimated to cold marine environment or experimentally immersed in cold water as compared with penguin juveniles that never experienced cold water immersion. Transcriptomic data were obtained by hybridizing penguins total cDNA on Affymetrix GeneChip Chicken Genome arrays and analyzed using maxRS algorithm , “ Transcriptome analysis in non-model species: a new method for the analysis of heterologous hybridization on microarrays ” (Degletagne et al., 2010) [1] . We focused on genes involved in multiple antioxidant pathways. For better clarity, these differentially expressed genes were clustered into six functional groups according to their role in controlling redox homeostasis. The data are related to a comprehensive research study on the ontogeny of antioxidant functions in king penguins, “Hormetic response triggers multifaceted anti-oxidant strategies in immature king penguins (Aptenodytes Patagonicus)” (Rey et al., 2016) [2] . The raw microarray dataset supporting the present analyses has been deposited at the Gene Expression Omnibus (GEO) repository under accessions GEO: GSE17725 and GEO: GSE82344 .
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Hormetic response triggers multifaceted anti-oxidant strategies in immature king penguins (Aptenodytes Patagonicus)
Free Radical Biology and Medicine, 2016Co-Authors: Benjamin Rey, Jean-louis Rouanet, Cyril Degletagne, Jacques Bodennec, Pierre-axel Monternier, Mathieu Mortz, Damien Roussel, Caroline Romestaing, Jérémy Tornos, Claude DuchampAbstract:Repeated deep dives are highly pro-oxidative events for air-breathing aquatic foragers such as penguins. At ␣edging, the transition from a strictly terrestrial to a marine lifestyle may therefore trigger a complex set of anti-oxidant responses to prevent chronic oxidative stress in immature penguins but these pro- cesses are still unde␣ned. By combining in vivo and in vitro approaches with transcriptome analysis, we investigated the adaptive responses of sea-acclimatized (SA) immature king penguins (Aptenodytes pa- tagonicus) compared with pre-␣edging never-immersed (NI) birds. In vivo, experimental immersion into cold water stimulated a higher thermogenic response in SA penguins than in NI birds, but both groups exhibited hypothermia, a condition favouring oxidative stress. In vitro, the pectoralis muscles of SA birds displayed increased oxidative capacity and mitochondrial protein abundance but unchanged reactive oxygen species (ROS) generation per g tissue because ROS production per mitochondria was reduced. The genes encoding oxidant-generating proteins were down-regulated in SA birds while mRNA abundance and activity of the main antioxidant enzymes were up-regulated. Genes encoding proteins involved in repair mechanisms of oxidized DNA or proteins and in degradation processes were also up-regulated in SA birds. Sea life also increased the degree of fatty acid unsaturation in muscle mitochondrial membranes resulting in higher intrinsic susceptibility to ROS. Oxidative damages to protein or DNA were reduced in SA birds. Repeated experimental immersions of NI penguins in cold-water partially mimicked the effects of acclimatization to marine life, modi␣ed the expression of fewer genes related to oxidative stress but in a similar way as in SA birds and increased oxidative damages to DNA. It is concluded that the multi- faceted plasticity observed after marine life may be crucial to maintain redox homeostasis in active tissues subjected to high pro-oxidative pressure in diving birds. Initial immersions in cold-water may initiate an hormetic response triggering essential changes in the adaptive antioxidant response to marine life.
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Effect of fasting on the VO2-fh relationship in king penguins, Aptenodytes Patagonicus.
American journal of physiology. Regulatory integrative and comparative physiology, 2004Co-Authors: Andreas Fahlman, Yves Handrich, A. J. Woakes, Charles A Bost, R.l. Holder, Claude Duchamp, Patrick J. ButlerAbstract:King penguins (Aptenodytes Patagonicus) may fast for up to 30 days during their breeding period. As such extended fasting may affect the relationship between the rate of O2 consumption (Vo2) and h...
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Superoxide activates a GDP-sensitive proton conductance in skeletal muscle mitochondria from king penguin (Aptenodytes Patagonicus).
Biochemical and biophysical research communications, 2003Co-Authors: Darren A. Talbot, Claude Duchamp, Nicolas Hanuise, Benjamin Rey, Jean-louis Rouanet, Martin D. BrandAbstract:We present the partial nucleotide sequence of the avian uncoupling protein (avUCP) gene from king penguin (Aptenodytes Patagonicus), showing that the protein is 88–92% identical to chicken (Gallus gallus), turkey (Meleagris gallopavo), and hummingbird (Eupetomena macroura). We show that superoxide activates the proton conductance of mitochondria isolated from king penguin skeletal muscle. GDP abolishes the superoxide-activated proton conductance, indicating that it is mediated via avUCP. In the absence of superoxide there is no GDP-sensitive component of the proton conductance from penguin muscle mitochondria demonstrating that avUCP plays no role in the basal proton leak.
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ontogeny of thermoregulatory mechanisms in king penguin chicks Aptenodytes Patagonicus
Comparative Biochemistry and Physiology A-molecular & Integrative Physiology, 2002Co-Authors: Claude Duchamp, Jean-louis Rouanet, Herve BarreAbstract:The rapid maturation of thermoregulatory mechanisms may be of critical importance for optimising chick growth and survival and parental energy investment under harsh climatic conditions. The ontogeny of thermoregulatory mechanisms was studied in growing king penguin chicks from hatching to the full emancipation observed at 1 month of age in the sub-Antarctic area (Crozet Archipelago). Newly hatched chicks showed small, but significant regulatory thermogenesis (21% rise in heat production assessed by indirect calorimetry), but rapidly became hypothermic. Within a few days, both resting (+32%) and peak (+52%) metabolic rates increased. The first week of life was characterised by a two-fold rise in thermogenic capacity in the cold, while thermal insulation was not improved. During the second and third weeks of age, thermal insulation markedly rose (two-fold drop in thermal conductance) in relation to down growth, while resting heat production was slightly reduced (-13%). Shivering (assessed by electromyography) was visible right after hatching, although its efficiency was limited. Thermogenic efficiency of shivering increased five-fold with age during the first weeks of life, but there was no sign of non-shivering thermogenesis. We conclude that thermal emancipation of king penguin chicks may be primarily determined by improvement of thermal insulation after thermogenic processes have become sufficiently matured. Both insulative and metabolic adaptations are required for the rapid ontogeny of thermoregulation and thermal emancipation in growing king penguin chicks.
René Groscolas - One of the best experts on this subject based on the ideXlab platform.
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Modulation of heart rate response to acute stressors throughout the breeding season in the king penguin Aptenodytes Patagonicus.
The Journal of experimental biology, 2015Co-Authors: Vincent A. Viblanc, Andrew D Smith, Benoit Gineste, Marion Kauffmann, René GroscolasAbstract:'Fight-or-flight' stress responses allow animals to cope adaptively to sudden threats by mobilizing energy resources and priming the body for action. Because such responses can be costly and redirect behavior and energy from reproduction to survival, they are likely to be shaped by specific life-history stages, depending on the available energy resources and the commitment to reproduction. Here, we consider how heart rate (HR) responses to acute stressors are affected by the advancing breeding season in a colonial seabird, the king penguin (Aptenodytes Patagonicus). We subjected 77 birds (44 males, 33 females) at various stages of incubation and chick-rearing to three experimental stressors (metal sound, distant approach and capture) known to vary both in their intensity and associated risk, and monitored their HR responses. Our results show that HR increase in response to acute stressors was progressively attenuated with the stage of breeding from incubation to chick-rearing. Stress responses did not vary according to nutritional status or seasonal timing (whether breeding was initiated early or late in the season), but were markedly lower during chick-rearing than during incubation. This pattern was obvious for all three stressors. We discuss how 'fight-or-flight' responses may be modulated by considering the energy commitment to breeding, nutritional status and reproductive value of the brood in breeding seabirds.
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Is territory defence related to plumage ornaments in the king penguin Aptenodytes Patagonicus
Ethology, 2008Co-Authors: Vanessa M. Viera, Steeve D. Côté, Pierre Jouventin, Paul M. Nolan, René GroscolasAbstract:Colourful ornaments in monogamous birds may be directed at potential mates or other conspecifics to signal individual condition, reproductive status or fighting ability, especially in monogamous and territorial species. We investigated whether the size of the orange auricular patch may be an indicator of aggressiveness in the king penguin Aptenodytes Patagonicus, a monogamous and territorial seabird. The relationship between auricular patch size and defence behaviour was explored relative to territory location (centre vs. periphery of the colony), period of reproduction (early vs. late), state of reproduction (incubation vs. brooding) and sex. The proportion of time spent in territorial defence and the rate of aggressive behaviours were positively correlated with auricular patch size, mainly because central birds were more aggressive than peripheral birds and also had larger patch sizes. The period of reproduction, state of reproduction and sex did not interact with patch size to affect aggressiveness. Our results suggest that the size of the auricular patch in king penguins may be a reliable signal allowing individuals to evaluate the quality of mates or competitors in terms of aggressiveness. Whether aggressiveness is directly linked to patch size or indirectly through body condition, however, remains to be determined. In any event, birds with larger patches seem to gain central territories in the colony, thereby increasing their reproductive success. Finally, our study adds to the growing evidence that the evolution of sexually monomorphic ornaments may stem from mutual sexual selection.
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nutrition physiology and stable isotopes new information from fasting and molting penguins
Ecology, 2005Co-Authors: Yves Cherel, Keith A Hobson, Frederic Bailleul, René GroscolasAbstract:Stable isotopes are increasingly used in animal ecology, but little attention has been paid to the underlying physiological processes accounting for changes in 15N/14N and 13C/12C ratios, for example, the influence of protein balance on δ15N values. We investigated a “professional” faster, the King Penguin (Aptenodytes Patagonicus), to test the effect of long-term food deprivation on the isotopic signature of tissues that can be nondestructively sampled, i.e., blood and feathers. Fasting for 25 days induced a tissue 15N enrichment, thus leading to a moderate increase in the apparent trophic levels of penguins. As expected, 15N enrichment was higher in tissues with high protein turnover rates (e.g., plasma, 0.70‰) than in those with low turnover rates (e.g., blood cells, 0.24‰). Fasting decreased the δ13C value of plasma, which was due to an increase in its lipid content, as indicated by a concomitant rise in plasma C/N ratio. Finally, food deprivation induced a 15N enrichment in keratin (1.68‰), as indica...
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Assessing a relationship between bone microstructure and growth rate: a fluorescent labelling study in the king penguin chick (Aptenodytes Patagonicus).
Journal of Experimental Biology, 2004Co-Authors: E. De Margerie, René Groscolas, Jean-patrice Robin, D. Verrier, Jorge Cubo, Jacques CastanetAbstract:SUMMARY Microstructure–function relationships remain poorly understood in primary bone tissues. The relationship between bone growth rate and bone tissue type, although documented in some species by previous works, remains somewhat unclear and controversial. We assessed this relationship in a species with extreme adaptations, the king penguin ( Aptenodytes Patagonicus ). These birds have a peculiar growth, interrupted 3 months after hatching by the austral winter. Before this interruption, chicks undergo extremely rapid statural and ponderal growth. We recorded experimentally (by means of fluorescent labelling) the growth rate of bone tissue in four long bones (humerus, radius, femur and tibiotarsus) of four king penguin chicks during their fastest phase of growth (3–5 weeks after hatching) and identified the associated bone tissue types (`laminar9, `longitudinal9, `reticular9 or `radial9 fibro-lamellar bone tissue). We found the highest bone tissue growth rate known to date, up to 171 μm day –1 (mean 55 μm day –1 ). There was a highly significant relationship between bone tissue type and growth rate ( P –6 ). Highest rates were obtained with the radial microarchitecture of fibro-lamellar bone, where cavities in the woven network are aligned radially. This result supports the heuristic value of a relationship between growth rate and bone primary microstructure. However, we also found that growth rates of bone tissue types vary according to the long bone considered ( P –5 ) (e.g. growth rates were 38% lower in the radius than in the other long bones), a result that puts some restriction on the applicability of absolute growth rate values (e.g. to fossil species). The biomechanical disadvantages of accelerated bone growth are discussed in relation to the locomotor behaviour of the chicks during their first month of life.
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Establishment of the fatty acid profile of the brain of the king penguin (Aptenodytes Patagonicus) at hatch: effects of a yolk that is naturally rich in n-3 polyunsaturates.
Physiological and biochemical zoology : PBZ, 2003Co-Authors: Brian K. Speake, Frederic Decrock, Peter F. Surai, Nicholas A.r. Wood, René GroscolasAbstract:Abstract Because the yolk lipids of the king penguin (Aptenodytes Patagonicus) contain the highest concentrations of long‐chain n‐3 polyunsaturated fatty acids yet reported for an avian species, the consequences for the establishment of the brain’s fatty acid profile in the embryo were investigated. To place the results in context, the fatty acid compositions of yolk lipid and brain phospholipid of the king penguin were compared with those from three other species of free‐living birds. The proportions of docosahexaenoic acid (22:6n‐3; DHA) in the total lipid of the initial yolks for the Canada goose (Branta canadensis), mallard (Anas platyrhynchos), moorhen (Gallinula chloropus), and king penguin were (% w/w of fatty acids) \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcomman...
Le Y Maho - One of the best experts on this subject based on the ideXlab platform.
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heart rate and energetics of free ranging king penguins Aptenodytes Patagonicus
The Journal of Experimental Biology, 2004Co-Authors: G Froget, Andreas Fahlman, A. J. Woakes, Le Y Maho, P J Butler, Gregoire Kuntz, Yves HandrichAbstract:The main objective of this study was to determine heart rate ( f h) and the energetic costs of specific behaviours of king penguins while ashore and while foraging at sea during their breeding period. In particular, an estimate was made of the energetic cost of diving in order to determine the proportion of dives that may exceed the calculated aerobic dive limit (cADL; estimated usable O2 stores/estimated rate of oxygen consumption during diving). An implanted data logger enabled f h and diving behaviour to be monitored from 10 free-ranging king penguins during their breeding period. Using previously determined calibration equations, it was possible to estimate rate of oxygen consumption ( V O2) when the birds were ashore and during various phases of their foraging trips. Diving behaviour showed a clear diurnal pattern, with a mixture of deep (>40 m), long (>3 min) and shallow (<40 m), short (<3 min) dives from dawn to dusk and shallow, short dives at night. Heart rate during dive bouts and dive cycles (dive + post-dive interval) was 42% greater than that when the birds were ashore. During diving, f h was similar to the `ashore' value (87±4 beats min–1), but it did decline to 76% of the value recorded from king penguins resting in water. During the first hour after a diving bout, f h was significantly higher than the average value during diving (101±4 beats min–1) and for the remainder of the dive bout. Rates of oxygen consumption estimated from these (and other) values of f h indicate that when at sea, metabolic rate (MR) was 83% greater than that when the birds were ashore [3.15 W kg–1 (–0.71, +0.93), where the values in parentheses are the computed standard errors of the estimate], while during diving bouts and dive cycles, it was 73% greater than the `ashore' value. Although estimated MR during the total period between dive bouts was not significantly different from that during dive bouts [5.44 W kg–1 (–0.30, +0.32)], MR during the first hour following a dive bout was 52% greater than that during a diving bout. It is suggested that this large increase following diving (foraging) activity is, at least in part, the result of rewarming the body, which occurs at the end of a diving bout. From the measured behaviour and estimated values of V O2, it was evident that approximately 35% of the dives were in excess of the cADL. Even if V O2 during diving was assumed to be the same as when the birds were resting on water, approximately 20% of dives would exceed the cADL. As V O2 during diving is, in fact, that estimated for a complete dive cycle, it is quite feasible that V O2 during diving itself is less than that measured for birds resting in water. It is suggested that the regional hypothermia that has been recorded in this species during diving bouts may be at least a contributing factor to such hypometabolism.
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foraging strategies of incubating and brooding king penguins Aptenodytes Patagonicus
Oecologia, 1998Co-Authors: J. B. Charrassin, Klemens Pütz, J. Lage, T. Dahier, C A Bost, T Zorn, Le Y MahoAbstract:For oceanic birds like king penguins, a major constraint is the separation of foraging areas from the breeding colony, largely because swimming increases foraging costs. However, the relationship between foraging strategy and breeding stage has been poorly investigated. Using time-depth recorders, we studied the diving behaviour of two groups of king penguins that were either incubating or brooding chicks at Crozet Islands (Southern Indian Ocean) at the same period of the year. Although birds with chicks had the highest predicted energy demand, they made foraging trips half as long as incubating birds (6 vs. 14 days) and modified their time and depth utilisation. Birds with chicks dived deeper during daylight (mean maximum depth of 280 m vs. 205 m for those incubating). At night, birds with chicks spent twice as much time diving as those incubating, but birds at both stages never dived beyond 30 m. Movements to greater depths by brooding birds are consistent with the vertical distribution of myctophid fish which are the main prey. As chick provisioning limits trip duration, it is suggested that it is more efficient for parents to change their diving patterns rather than to restrict their foraging range.
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core temperature variability in diving king penguins Aptenodytes Patagonicus a preliminary analysis
Polar Biology, 1996Co-Authors: B M Culik, Klemens Pütz, Rory P Wilson, C A Bost, Le Y Maho, J L VerselinAbstract:Core temperature was determined in two king penguins living in the wild at Ile de la Possession, Crozel Archipelago, using implantable four-channel temperature loggers. Core temperatures derived from bird no. 1 (sensor placed under the sternum, in the vicinity of the liver and upper stomach) were closely correlated with diving activity (as determined by an external light recorder), and ranged from 38.3°C, (on land) to a minimum of 37.2°C during a dive. Core temperatures measured in bird no. 2 showed that temperatures near the heart were generally 1°C lower than those under the sternum or in the lower abdomen. Core temperatures declined continuously during dives (by 0.8, 1.2 and 2.7°C in the lower abdomen, under the sternum and near the heart, respectively) and showed precipitous drops to 35°C, probably associated with ingestion of food. Temperatures measured near the heart fluctuated over a period of 288 s, corresponding to the duration (from the literature) of the surface/dive cycle. The relevance of these findings with respect to diving physiology, blood perfusion of tissues, tissue metabolism and aerobic dive limits is discussed.
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diving energetics in king penguins Aptenodytes Patagonicus
The Journal of Experimental Biology, 1996Co-Authors: B M Culik, Klemens Pütz, J. Lage, Rory P Wilson, D Allers, C A Bost, Le Y MahoAbstract:Dive duration in wild king penguins and the energetic cost of swimming in a 30m long swim channel were determined at Ile de la Possession, Crozet Archipelago, using external data loggers and respirometry, respectively. Calibrated electronic data loggers equipped with a pressure sensor were used to determine dive durations: 95% of dives were less than 6 min long and 66% of dives were less than 4 min long. Dive patterns show that king penguins may intersperse long dive durations (4-6.3 min) with short ones (1.5-3 min) and make surface pauses of variable duration between them (0.5-3.5 min), or dive regularly (for up to 5 h) with long dive durations (5 min) and constant interdive surface intervals (1.5 min). The latter indicates that the aerobic dive limits (ADL) of this species could be higher and oxygen consumption lower than previously reported. Assuming that king penguins dive within their aerobic limit, different approaches to the analysis of the data obtained in the swim channel are discussed to derive the ADL. Swimming speeds observed in the channel ranged from 0.9 to 3.4 m s-1. Transport costs were lowest between 1.8 and 2.2 m s-1. Although at 2.2 m s-1 king penguins used only 10.3 Wkg-1 over a dive+surface cycle (minimal transport costs of 4.7 J kg-1 m-1), we speculate that tisse oxygen consumption during submergence may be as low as 0.23 ml O2 kg-1 s-1 (2.1 times standard metabolic rate, SMR) or perhaps lower (which gives an ADL of 4.2 min). During surface phases, oxygen uptake would be increased to at least 1 ml O2kg-1 s-1 (9.3 times SMR). This implies that at least 70% of all dives are aerobic. Potential physiological mechanisms allowing king penguins to partition O2 consumption between submergence and surface periods remain, however, unclear.
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nutrient reserve dynamics and energetics during long term fasting in the king penguin Aptenodytes Patagonicus
Journal of Zoology, 1994Co-Authors: Yves Cherel, Yves Handrich, J Gilles, Le Y MahoAbstract:Males of king penguins (Aptenodytes Patagonicus) naturally fast during one month at the beginning of their breeding cycle in the sub-Antarctic islands. Previous qualitative data have shown that this species adapts to prolonged fasting by mobilizing fat stores and minimizing protein loss and that this strategy ends with a progressive increase in protein utilization. In the present study, the quantification of nutrient utilization from body composition of captive birds indicates that, during the phase of protein conservation, 93% of the energy produced derives from the oxidation of fat stores, body protein accounting for the remainder (7%). Tissue composition analysis shows that integument (feathers, skin and subdermal fat) is the main lipid source (65% of the fat loss) during this period, and that pectoral muscles provide the majority of body protein (57% of the total loss). If the fast is prolonged until a body mass below 10 kg is reached, there is a progressive four-fold increase (from 1 68 to 6.50 gN/24h) in nitrogen excretion, together with a progressive exhaustion of fat stores. This shift in fuel metabolism is not a direct consequence of total lipid depletion, because 22% of the initial fat content still remains when proteins are no longer spared. During this later metabolic phase, protein is not only provided by pectoral muscles (71% of the loss), but also by hindlimb muscles (13%), and there remains only 2% of the initial amount of lipid in the integument at the end of the fast. Total energy expenditure is close to the fasting basal metabolic rate during the phase of protein conservation (2.52 W/kg), but it increases by 33% (3.36 W/kg) during the phase of protein wasting. This difference is probably due to a rise in locomotor activity, that is interpreted as reflecting a stimulation of food foraging behaviour before the lethal depletion of nutrient reserves.
Yves Handrich - One of the best experts on this subject based on the ideXlab platform.
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accelerometry predicts prey capture rates in the deep diving king penguin Aptenodytes Patagonicus
Marine Biology, 2021Co-Authors: Yves Handrich, Emile Brissoncuradeau, Kyle H Elliott, Charles-andré BostAbstract:Remotely estimating prey-capture rates in wild animals is key to assess foraging success. In diving animals, accelerometers have been particularly useful to remotely detect prey captures and have been shown to be more precise than traditional estimates relying on depth-derived measures (e.g., wiggles). However, validations of the accelerometry technique using a gold standard (i.e., with supervision) have been mostly restricted to shallow diving species, which can be equipped with camera-loggers for visual validation of prey-capture events. In species diving near the euphotic limit (150–200 m), accelerometers remain mostly untested due to the difficulty of validating such methods in darkness at extreme depth in the wild. In addition, prey-pursuits in low-light conditions might not result in intense and long-duration acceleration signatures, as predator–prey perception likely occurs at close-range in the dark (i.e., the “visual-interactions hypothesis”). We combined accelerometers with beak-opening sensors (for validation) and depth recorders on a wild deep-diving seabird, the king penguin Aptenodytes Patagonicus, to describe prey captures at depth and create predictive models using accelerometers. Surprisingly, prey pursuits and captures were similar in duration (3.9 ± 3.5 s) and intensity (0.78 ± 0.31 g) as shallow-diving species reported by similar studies. As accelerometry signatures were distinct, accelerometry-derived variables were almost twice as accurate (Mean-squared error = 8.6) at predicting prey-capture events as depth-derived variables (“wiggles”, Mean-squared error = 16.0). As in the shallow-diving species, accelerometry outperforms traditional depth-derived models at measuring the foraging intake in deep-diving animals, highlighting the usefulness of accelerometers for measuring animal behavior.
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First detection of Borrelia burgdorferi sensu lato DNA in king penguins (Aptenodytes Patagonicus halli)
Ticks and Tick-borne Diseases, 2014Co-Authors: Frédéric Schramm, Yves Handrich, Michel Gauthier-clerc, Yvon Le Maho, Jean-charles Fournier, Karen D. Mccoy, Cathy Barthel, Danièle Postic, B. JaulhacAbstract:The hard tick Ixodes uriae parasitises a wide range of seabird species in the circumpolar areas of bothNorthern and Southern hemispheres and has been shown to be infected with Borrelia burgdorferi sensulato, the bacterial agents of Lyme borreliosis. Although it is assumed that seabirds represent viable reservoirhosts, direct demonstrations of infection are limited to a single study from the Northern hemisphere.Here, the blood of 50 tick-infested adult king penguins (Aptenodytes Patagonicus halli) breeding in theCrozet Archipelago (Southern Indian Ocean) was examined for B. burgdorferi sl exposure by serology andfor spirochetemia by in vitro DNA amplification. Four birds were found positive by serology, whereas B.burgdorferi sl DNA was detected in two other birds. Our data therefore provide the first direct proof ofBorrelia burgdorferi sl spirochetes in seabirds of the Southern hemisphere and indicate a possible reservoirrole for king penguins in the natural maintenance of this bacterium. Although the bacterial geneticdiversity present in these hosts and the infectious period for tick vectors remain to be elucidated, ourresults add to a growing body of knowledge on the contribution of seabirds to the complex epizootiologyof Lyme disease and the global dissemination of B. burgdorferi sl spirochetes.
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pressure equilibration in the penguin middle ear
Acta Oto-laryngologica, 2008Co-Authors: Jacob Sade, Yves Handrich, Joelle Bernheim, David CohenAbstract:Conclusions. King penguins have a venous structure in the form of a corpus cavernosum (CC) in their middle ear (ME) submucosa. The CC may be viewed as a special organelle that can change ME volume for pressure equilibration during deep-sea diving it is a pressure regulating organelle (PRO). A similar CC and muscles also surround the external ear (EE) and may constrict it, isolating the tympanic membrane from the outside. A CC was previously found also in the ME of marine diving mammals and can be expected to exist in other deep diving animals, such as marine turtles. Objectives. Marine animals require equalization of middle ear (ME) pressure when diving hundreds or thousands of meters to catch prey. We investigated what mechanism enables king penguins to protect their ME when they dive to great depths. Materials and methods. Biopsies and serial sections of the ME and the EE of the deep diving king penguin (Aptenodytes Patagonicus) were examined microscopically. Results. It was demonstrated that the pengui...
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Fine-scale analyses of diving energetics in king penguins Aptenodytes Patagonicus: how behaviour affects costs of a foraging dive
Marine Ecology Progress Series, 2007Co-Authors: L.g. Halsey, Andreas Fahlman, Yves Handrich, A. J. Woakes, R.l. Holder, Charles-andré Bost, A. Schmidt, P J ButlerAbstract:Heart rate data loggers were implanted into king penguins Aptenodytes Patagonicus undertaking foraging trips at sea during three austral summers. Data were obtained from a total of 20 king penguins. Our aim was to investigate variations in mean heart rate over the dive cycle (i.e. dive plus the subsequent surface period) with changes in diving behaviour, at the scale of the individual foraging dive. From these heart rate values, energetic costs were estimated in terms of rate of oxygen consumption. Shorter dive durations and longer surface durations were associated with statistically significantly higher mean heart rates, and hence energetic costs, over the dive cycle. A decrease in the duration of the bottom period of dives was also associated with an increase in heart rate and energetic costs. In contrast to model predictions that power requirements of swimming in penguins increase rapidly with increasing speed, in the main, the number of wiggles (i.e. intensive prey pursuits lasting several seconds) in a dive did not affect mean heart rate. Furthermore, the shape of the dive did not affect mean heart rate. Diving behaviour and mean heart rates over the dive cycle of birds during 2 austral summers was compared. While the birds in the earlier austral summer undertook considerably longer foraging trips than did the birds in the latter summer, mean mass gain while at sea was similar. Birds during the latter summer exhibited statistically significantly longer dive durations and bottom durations and dived to statistically significantly shallower depths than birds during the earlier summer. However, this did not translate into a statistically significantly lower mean heart rate over the dive cycle in these birds. This suggests that the differences in dive time budgeting between the two summers had only a relatively subtle effect on mean heart rate. In turn the relationship between diving behaviour and foraging success in king penguins may be more obvious than that between diving behaviour and mean heart rate over the dive cycle.
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heart rate and energetics of free ranging king penguins Aptenodytes Patagonicus
The Journal of Experimental Biology, 2004Co-Authors: G Froget, Andreas Fahlman, A. J. Woakes, Le Y Maho, P J Butler, Gregoire Kuntz, Yves HandrichAbstract:The main objective of this study was to determine heart rate ( f h) and the energetic costs of specific behaviours of king penguins while ashore and while foraging at sea during their breeding period. In particular, an estimate was made of the energetic cost of diving in order to determine the proportion of dives that may exceed the calculated aerobic dive limit (cADL; estimated usable O2 stores/estimated rate of oxygen consumption during diving). An implanted data logger enabled f h and diving behaviour to be monitored from 10 free-ranging king penguins during their breeding period. Using previously determined calibration equations, it was possible to estimate rate of oxygen consumption ( V O2) when the birds were ashore and during various phases of their foraging trips. Diving behaviour showed a clear diurnal pattern, with a mixture of deep (>40 m), long (>3 min) and shallow (<40 m), short (<3 min) dives from dawn to dusk and shallow, short dives at night. Heart rate during dive bouts and dive cycles (dive + post-dive interval) was 42% greater than that when the birds were ashore. During diving, f h was similar to the `ashore' value (87±4 beats min–1), but it did decline to 76% of the value recorded from king penguins resting in water. During the first hour after a diving bout, f h was significantly higher than the average value during diving (101±4 beats min–1) and for the remainder of the dive bout. Rates of oxygen consumption estimated from these (and other) values of f h indicate that when at sea, metabolic rate (MR) was 83% greater than that when the birds were ashore [3.15 W kg–1 (–0.71, +0.93), where the values in parentheses are the computed standard errors of the estimate], while during diving bouts and dive cycles, it was 73% greater than the `ashore' value. Although estimated MR during the total period between dive bouts was not significantly different from that during dive bouts [5.44 W kg–1 (–0.30, +0.32)], MR during the first hour following a dive bout was 52% greater than that during a diving bout. It is suggested that this large increase following diving (foraging) activity is, at least in part, the result of rewarming the body, which occurs at the end of a diving bout. From the measured behaviour and estimated values of V O2, it was evident that approximately 35% of the dives were in excess of the cADL. Even if V O2 during diving was assumed to be the same as when the birds were resting on water, approximately 20% of dives would exceed the cADL. As V O2 during diving is, in fact, that estimated for a complete dive cycle, it is quite feasible that V O2 during diving itself is less than that measured for birds resting in water. It is suggested that the regional hypothermia that has been recorded in this species during diving bouts may be at least a contributing factor to such hypometabolism.
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Transcriptomic data analysis and differential gene expression of antioxidant pathways in king penguin juveniles (Aptenodytes Patagonicus) before and after acclimatization to marine life.
Data in brief, 2016Co-Authors: Benjamin Rey, Cyril Degletagne, Claude DuchampAbstract:Abstract In this article, we present differentially expressed gene profiles in the pectoralis muscle of wild juvenile king penguins that were either naturally acclimated to cold marine environment or experimentally immersed in cold water as compared with penguin juveniles that never experienced cold water immersion. Transcriptomic data were obtained by hybridizing penguins total cDNA on Affymetrix GeneChip Chicken Genome arrays and analyzed using maxRS algorithm , “ Transcriptome analysis in non-model species: a new method for the analysis of heterologous hybridization on microarrays ” (Degletagne et al., 2010) [1] . We focused on genes involved in multiple antioxidant pathways. For better clarity, these differentially expressed genes were clustered into six functional groups according to their role in controlling redox homeostasis. The data are related to a comprehensive research study on the ontogeny of antioxidant functions in king penguins, “Hormetic response triggers multifaceted anti-oxidant strategies in immature king penguins (Aptenodytes Patagonicus)” (Rey et al., 2016) [2] . The raw microarray dataset supporting the present analyses has been deposited at the Gene Expression Omnibus (GEO) repository under accessions GEO: GSE17725 and GEO: GSE82344 .
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Hormetic response triggers multifaceted anti-oxidant strategies in immature king penguins (Aptenodytes Patagonicus)
Free Radical Biology and Medicine, 2016Co-Authors: Benjamin Rey, Jean-louis Rouanet, Cyril Degletagne, Jacques Bodennec, Pierre-axel Monternier, Mathieu Mortz, Damien Roussel, Caroline Romestaing, Jérémy Tornos, Claude DuchampAbstract:Repeated deep dives are highly pro-oxidative events for air-breathing aquatic foragers such as penguins. At ␣edging, the transition from a strictly terrestrial to a marine lifestyle may therefore trigger a complex set of anti-oxidant responses to prevent chronic oxidative stress in immature penguins but these pro- cesses are still unde␣ned. By combining in vivo and in vitro approaches with transcriptome analysis, we investigated the adaptive responses of sea-acclimatized (SA) immature king penguins (Aptenodytes pa- tagonicus) compared with pre-␣edging never-immersed (NI) birds. In vivo, experimental immersion into cold water stimulated a higher thermogenic response in SA penguins than in NI birds, but both groups exhibited hypothermia, a condition favouring oxidative stress. In vitro, the pectoralis muscles of SA birds displayed increased oxidative capacity and mitochondrial protein abundance but unchanged reactive oxygen species (ROS) generation per g tissue because ROS production per mitochondria was reduced. The genes encoding oxidant-generating proteins were down-regulated in SA birds while mRNA abundance and activity of the main antioxidant enzymes were up-regulated. Genes encoding proteins involved in repair mechanisms of oxidized DNA or proteins and in degradation processes were also up-regulated in SA birds. Sea life also increased the degree of fatty acid unsaturation in muscle mitochondrial membranes resulting in higher intrinsic susceptibility to ROS. Oxidative damages to protein or DNA were reduced in SA birds. Repeated experimental immersions of NI penguins in cold-water partially mimicked the effects of acclimatization to marine life, modi␣ed the expression of fewer genes related to oxidative stress but in a similar way as in SA birds and increased oxidative damages to DNA. It is concluded that the multi- faceted plasticity observed after marine life may be crucial to maintain redox homeostasis in active tissues subjected to high pro-oxidative pressure in diving birds. Initial immersions in cold-water may initiate an hormetic response triggering essential changes in the adaptive antioxidant response to marine life.
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Superoxide activates a GDP-sensitive proton conductance in skeletal muscle mitochondria from king penguin (Aptenodytes Patagonicus).
Biochemical and biophysical research communications, 2003Co-Authors: Darren A. Talbot, Claude Duchamp, Nicolas Hanuise, Benjamin Rey, Jean-louis Rouanet, Martin D. BrandAbstract:We present the partial nucleotide sequence of the avian uncoupling protein (avUCP) gene from king penguin (Aptenodytes Patagonicus), showing that the protein is 88–92% identical to chicken (Gallus gallus), turkey (Meleagris gallopavo), and hummingbird (Eupetomena macroura). We show that superoxide activates the proton conductance of mitochondria isolated from king penguin skeletal muscle. GDP abolishes the superoxide-activated proton conductance, indicating that it is mediated via avUCP. In the absence of superoxide there is no GDP-sensitive component of the proton conductance from penguin muscle mitochondria demonstrating that avUCP plays no role in the basal proton leak.