King Penguin Chicks Research Articles

Nonshivering thermogenesis and adaptation to fasting in king penguin chicks.

The ability to develop nonshivering thermogenesis (NST) and the effect of fasting on thermogenic response to cold were studied in winter-acclimatized king penguin chicks. Metabolic rate (MR) and integrated electrical muscle activity were measured at different ambient temperatures. In cold-acclimatized (5 degrees C) fed chicks, shivering threshold temperature (STT) was 9.4 degrees C lower than lower critical temperature (LCT), indicating that NST (0.7 W/kg) occurs at moderate cold, whereas in control chicks fed and reared at 25 degrees C for 3 wk, LCT and STT were similar. Chicks reared in the cold and fasting for 3 wk or 4-5 mo (natural winter fast) developed an NST of 0.8 and 2.4 W/kg, respectively, despite the fast. In fasting chicks, the intercept of the metabolic curve with the abscissa at zero MR was far below body temperature, contrasting with the classic model for heat loss. Their low LCT indicates the capacity of a large reduction in convective conductance characteristic of diving animals and allows energy sparing in moderate cold. Below LCT, conductance reincreases progressively, leading to a steeper than expected slope of the metabolic curve and allowing preservation of a threshold temperature in the shell. These results show for the first time in a wild young bird the development of NST after cold acclimatization. Further, at the temperature of cold acclimatization, an energy-sparing mechanism is shown in response to long-term fast adaptation.

Plasma hormone levels in relation to lipid and protein metabolism during prolonged fasting in king penguin chicks

Chicks of king penguin ( Aptenodytes patagonica), while only 3–4 months old, tolerate 4–6 months of fasting when they are abandoned by their parents during the subantarctic winter. The body mass of nine chicks, which were followed during this natural winter fast, was 13.1 kg at capture and 3.4 kg after 150 days of fasting, a 74% decrease. The longer phase II (129 days) was marked by lipid mobilization and protein sparing, as indicated by a continuous increase in plasma levels of free fatty acids, glycerol, and (3-hydroxybutyrate, whereas plasma alanine, uric acid, and urea remained stable at low values. In phase III, by contrast, plasma concentrations of lipid-derived metabolites decreased, while plasma alanine, uric acid, and urea increased markedly, indicating an increase in protein utilization. Plasma insulin concentration did not significantly change during either phase II or phase III. Plasma glucagon remained constant during phase II and at the beginning of phase III but increased 2.6 times afterward. Plasma corticosterone increased only slightly during the first 4 months of the fast but reached very high values at the end of phase II and the beginning of phase III (4.7 times basal values); moreover, it further increased 3.1 times before phase III was stopped. Altogether, these data accord with the idea that the outstanding resistance of king penguin chicks to starvation is due to the ability to extensively prolong the situation of protein sparing, which seems to require the maintenance of low plasma concentrations of corticosterone and insulin for up to 4 months. The further increase in protein utilization may be attributed to the rise in corticosterone which then occurs, while the high plasma glucagon could enhance gluconeogenesis from amino acids when lipid stores are progressively depleted.

Early changes in plasma hormones and metabolites during fasting in king penguin chicks.

Chicks of the king penguin (Aptenodytes patagonica) can tolerate a fast of 4-6 months during the subantarctic winter. The aim of this work was to study their initial response to food deprivation. Nine chicks were starved for 18 days. Two phases of starvation were defined according to changes in the specific daily loss in body mass: it decreased by 92% in phase I (6.6 +/- 0.3 days) and remained steady and low in phase II. Phase I was marked by a large decline in protein utilization, indicated by decreases in plasma levels of alanine (58%), uric acid (89%) and urea (76%) together with a decrease in circulating corticosterone (60%) and thyroxine (75%). In phase I, plasma insulin concentration decreased (61%) in some birds, but did not change in others; plasma pancreatic glucagon was stable whereas gut-glucagon decreased by 75%. Free fatty acids and beta-hydroxybutyrate concentrations gradually rose during the fast to 5 to 6 times pre-fast levels. Glycemia remained unchanged. Phase II was characterized by no change in plasma concentrations of protein-derived metabolites and by no or little change in circulating hormone levels. From comparison with previous data, we conclude that there are similar early adjustments to food deprivation in king penguin chick, rat and man: (1) a decrease in resting metabolic rate, (2) a decrease in protein utilization, and (3) mobilization of fat stores. The key adaptations to long-term fasting in these species are therefore effectiveness in protein sparing and ability to prolong this situation.(ABSTRACT TRUNCATED AT 250 WORDS)

Changes in Body Mass and Plasma Metabolites during Short-Term Fasting in the King Penguin

Journal Article Changes in Body Mass and Plasma Metabolites during Short-Term Fasting in the King Penguin Get access Yves Cherel, Yves Cherel Laboratoire d’Etude des Regulations Physiologiques, associed aI’Universite Louis Pasteur, Centre National de la Recherche Scientifique, 23 rue Becquerel,6 7087 Strasbourg, France Search for other works by this author on: Oxford Academic Google Scholar Yvon Le Maho Yvon Le Maho Laboratoire d’Etude des Regulations Physiologiques, associed aI’Universite Louis Pasteur, Centre National de la Recherche Scientifique, 23 rue Becquerel,6 7087 Strasbourg, France Search for other works by this author on: Oxford Academic Google Scholar The Condor, Volume 90, Issue 1, 1 February 1988, Pages 257–258, https://doi.org/10.2307/1368462 Published: 01 February 1988 Article history Received: 03 April 1987 Accepted: 28 September 1987 Published: 01 February 1988

Les trois jeûnes du Manchot royal. Comparaison avec le jeûne de reproduction du Manchot empereur

Protein sparing is a major factor for surviving starvation. To investigate its mechanisms, which are still largely unknown, antarctic penguins are remarkable animal models. Under natural conditions, they tolerate extremely long fasts, which facilitate the comparison of the successive phases characterizing changes in the utilization of protein and lipid reserves . Our investigations demonstrate that the daily body mass loss per unit body mass reflects protein catabolism. The high efficiency of male Emperor penguin and King penguin chicks for protein sparing seems to be related to the large lipid reserves they store before fasting

Ecology and Physiology of Fasting in King Penguin Chicks

Abstract Captive King Penguin (Aptenodytes patagonica) chicks can fast for 5 months during the subantarctic winter with a 70% decrease in body mass. To investigate the adaptive value of this remarkable resistance to starvation, we compared captive chicks with free-ranging chicks in their colony at Possession Island, Crozet Archipelago. The chicks in the colony, from mid-April to beginning of September (i.e. all winter) were fed only every 39 days by their parents; some were not fed at all. In spring (October-December) the surviving chicks were fed every 6 days, and their growth was completed. Overall chick mortality in the colony during the winter and subsequent spring was about 50%. Mortality was highest in October, 6 months after the beginning of the winter, and may be attributed mainly to starvation. The decrease in body mass in the free-ranging chicks was remarkably similar to that for captive birds. In both groups, three periods were characterized according to the observed changes in the daily decrease in body mass per unit body mass (dm/mdt): dm/mdt dropped during the first period (I) of 5-6 days, was minimum and steady during period II, which lasted about 4 months, and increased in period III. Blood analysis of the captive chicks indicated the three periods correspond to modifications in protein breakdown. An initial decrease in uricacidemia indicates period I is a short period of transition, marked by a decrease in protein breakdown. In period II a minimum and constant uricacidemia, in parallel with a progressive increase in ketonemia, indicates efficient protein sparing while most of the energy is derived from lipids. Period III is critical because, from a rise in uricacidemia concomitant with a decreasing ketonemia, proteins are no longer spared. The extreme resistance of King Penguin chicks to starvation in winter may be explained partly by the ability to spare proteins for several months (period II). It occurs at a growth stage when the parents' feeding visits are rare. Other laboratory and field investigations of birds suggest that the means by which a wide variety of domestic and wild species adapt to fasting also may be interpreted in terms of three periods corresponding to changes in protein breakdown.

Five months of fasting in king penguin chicks: body mass loss and fuel metabolism.

When king penguin chicks are 3-4 mo old, they enter a season of interrupted growth due to long periods of fasting, because they are irregularly fed in winter. Nine captive chicks [mean initial body mass (m) = 12.5 kg] had fasted an average of 5 mo at the end of the experiment; m was then 4.0 kg, a 68% decrease. They probably could have fasted longer, since chicks of parents delayed in the return to the colony die from starvation at an m of 3.0 kg. The long fast could be divided into three periods based on the changes in rate of decrease of m. The remarkable resistance of king penguin chicks to starvation may be partly explained by their ability to maintain protein sparing for as much as 4 mo, the duration of period II; plasma concentrations of uric acid, urea, and alanine were then minimum, 0.1, 0.4, and 0.4 mmol X l-1 respectively. Particular changes during this period, i.e., progressive increase of beta-hydroxybutyrate and decrease of glucose concentrations, might contribute to the efficiency of protein sparing. Period III was marked by a rise in protein utilization, plasma concentrations of uric acid, urea, and alanine increasing to 0.7, 1.5, and 0.8 mmol X l-1, respectively.

Metabolic and insulative changes in winter- and summer-acclimatized King Penguin chicks

The effect of photoperiod and cold on metabolic and insulative changes was investigated in winter- and summer-acclimatized King Penguin chicks under natural conditions (in subantarctic climate). Non-shivering thermogenesis was also studied.

Calorigenic effect of glucagon and catecholamines in king penguin chicks

The calorigenic action of glucagon and catecholamine infusion was evaluated in winter-acclimatized king penguin chicks at 20 and 0 degrees C ambient temperature (Ta). At Ta = 20 degrees C the mean increase in metabolic rate was 0.73 W . kg-1 for epinephrine (80 micrograms . kg-1), 0.42 W . kg-1 for norepinephrine (150 micrograms . kg-1), and 1.16 W . kg-1 for glucagon (0.75 micrograms . kg-1); i.e., respectively 30, 17, and 47% of the control value. The maximum response to glucagon reached 89% over control. At Ta = 0 degrees C, for the same glucagon infusion, the mean increase in specific metabolic rate was 0.84 W . kg-1, 27% of control rate. In the cold, glucagon infusion inhibited shivering and substituted its calorigenic action, resulting in a less apparent effect. In contrast with the negligible effect of catecholamines, glucagon infused at low doses exerted a powerful calorigenic action in young king penguins and could be considered as a possible nonshivering thermogenesis mediator.

Populations of Surface-nesting Seabirds at Marion Island, 1994/95–2002/03

During the 1990s and early 2000s, populations of surface-nesting seabirds at Marion Island showed different trends, but for the majority of species numbers decreased. Reduced numbers of gentoo penguins Pygoscelis papua, eastern rockhopper penguins Eudyptes chrysocome filholi, Crozet shags Phalacrocorax [atriceps] melanogenis and probably macaroni penguins E. chrysolophus are most plausibly attributed to an altered availability of food. Decreases in numbers of dark-mantled sooty albatrosses Phoebetria fusca, light-mantled sooty albatrosses P. palpebrata, southern giant petrels Macronectes giganteus and possibly northern giant petrels M. halli may have resulted from mortality of birds in longline fisheries. However, populations of wandering Diomedea exulans and grey-headed Thalassarche chrysostoma albatrosses fluctuated around a stable level. Numbers of Subantarctic skuas Catharacta antarctica and kelp gulls Larus dominicanus breeding at Marion Island also decreased. Kerguelen Sterna virgata and Antarctic S. vittata terns remain scarce at the island. Trends for king penguins Aptenodytes patagonicus were not reliably gauged, but numbers probably remained stable or increased. There were large fluctuations in numbers of king penguin chicks surviving to the end of winter.

The Zoological Society of Scotland

THE increase in the number of visitors to the Zoological Park near Edinburgh to just short of half a million, and a surplus on the year's working of £1,708, indicate the material success of this Society (Ann. Report Zoo. Soc. Scot., 1936–37). In other ways it has made notable progress. The new open-air enclosure for tigers, which occupies the site of an old sandstone quarry, is a most striking example of the use of natural rock, and a new restaurant, made necessary by the increase of visitors, has been completed and opened. During the year five king penguin chicks were hatched, of which three were successfully reared, and amongst mammals there were born and reared lion cubs, four beavers, three llamas, a nilghai and Barbary sheep. The chimpanzee born in January 1936 has developed well, and for many years the breeding of tropical freshwater fishes has been a feature of the Carnegie Aquarium. A successful innovation was the holding of a series of meetings of members at which lectures upon, and illustrated accounts of, their investigations of animal habits and behaviour were given by experts.

New Penguin-breeding Record at Edinburgh

THE Scottish National Zoological Park at Edinburgh has long been famous for its penguins—not only for their number and variety and fine condition but also for the manner in which they have bred there. The king penguin bred first in the Park eighteen years ago, and since that time fifteen king penguin chicks have been bred and reared. The ringed penguin and the rockhopper penguin both bred in the Park two years ago. These were the first occasions on which these three species have bred in Britain, and probably the first time they have bred in captivity anywhere. The latest achievement of this kind is the breeding of the gentoo penguin. The gentoo penguin comes next in size to the king penguin. While the king penguin makes no nest but holds its single egg on its feet during incubation, and the rockhopper penguin and ringed penguin make a rough nest of a heap of pebbles, the gentoo penguin prefers something softer, and collects dead grass, twigs and small sticks which it shapes into a symmetrical nest. It was nearly two months after the beginning of the nest building that the first egg was laid, and a second egg was laid five days after the first. Both parents shared in the work of incubation, and took their turns fairly regularly. The first egg hatched after an incubation period of five weeks and four days, but the second was infertile. The chick has a nestling coat of pale grey on the back and white underneath, and it was observed to feed on the day it hatched. It feeds, as do all 'baby' penguins, by taking partially digested fish from the throat of the parent bird.

V.—The Moulting of the King Penguin (Aptenodytes patagonica)

As the King Penguin chick grows, the down tassels forming the prepennæ increase in length until they measure from 50 to 75 mm. (2 to 3 inches) over the greater part of the body. Some of the barbs of the juvenile down carry for some time natal down barbs on their tips, and the inner ends of all the barbs forming the tassels are eventually found to be continuous with barbs of either the main shaft or the aftershaft of the developing true feathers. How long the down coat is worn by any given King Penguin is not definitely known—it is said that King Penguins may not moult the prepennæ until they are nearly a year old; neither is it known at what time of the year the majority of the King Penguins living under natural conditions in South Georgia shed their prepennæ, or how long the moulting process usually lasts.