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Author  |
Verrier Delphine, Groscolas René, Guinet Christophe, Arnould John P Y, |
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Title |
Development of fasting abilities in subantarctic fur seal pups: balancing the demands of growth under extreme nutritional restrictions
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Type |
Journal Article |
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Year |
2011 |
Publication |
Functional Ecology |
Abbreviated Journal |
0269-8463 |
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Volume |
25 |
Issue |
3 |
Pages |
704-717 |
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Keywords |
body fat, energy conservation, fuel partitioning, growth strategy, maternal care, offspring survival, pinnipeds, protein sparing, |
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Abstract |
1.Surviving prolonged food deprivation requires various metabolic adaptations such as energy and protein sparing, which can be highly conflicting with energy-demanding stages of an animals life history such as growth. 2.Due to the maternal attendance pattern, subantarctic fur seal (Arctocephalus tropicalis Gray) pups must repeatedly endure exceptionally long fasts of increasing duration throughout the 10-month lactation period. Little is known of (i) how these infants adapt to such extreme energetic constraints while sustaining growth and development; and (ii) the ecological implications of repeated prolonged fasting in early life in terms of offspring survival, maternal care and growth strategy in this species, as well as the evolutionary consequences of such life history trait. 3.Physiological responses to prolonged fasting and how they change with development throughout the pre-weaning period were investigated. Results show that beginning with their first fast, subantarctic fur seal pups are able to mobilize lipid reserves preferentially while conserving protein stores in response to nutritional deprivation. As pup age, profound changes in energy expenditure allow the implementation of an efficient strategy of fat storage and lean body mass preservation, which proves highly adaptive in the face of the low maternal provisioning rates experienced. 4.Despite increasing fasting durations, pup mortality decreased markedly throughout the maternal dependence period. Consistent with predictions, field measurements indicate that fasting endurance, although limited in early life, increases up to durations of nearly 3 months with age. Results suggest that the maternal provisioning strategy could be constrained by these ontogenetic changes in pup fasting abilities. 5.Furthermore, extreme energetic constraints and local density-dependent effects appear to exert a strong selective pressure upon the adoption of a convergent growth strategy between the sexes aiming to maximize fat storage and pre-weaning survival. 6.The issues of resulting trade-offs between pre- and post-weaning survival and the evolutionary consequences of extreme fasting abilities are also addressed.
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109;119 |
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Bachelor's thesis |
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Blackwell Publishing Ltd |
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1365-2435 |
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yes |
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Serial |
3277 |
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Author |
Verrier Delphine, Groscolas René, Guinet Christophe, Arnould John P Y, |
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Title |
Development of fasting abilities in subantarctic fur seal pups: balancing the demands of growth under extreme nutritional restrictions
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Type |
Journal Article |
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Year |
2011 |
Publication |
Functional Ecology |
Abbreviated Journal |
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Volume |
25 |
Issue |
3 |
Pages |
704-717 |
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Keywords |
body fat, energy conservation, fuel partitioning, growth strategy, maternal care, offspring survival, pinnipeds, protein sparing, |
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Abstract |
1.Surviving prolonged food deprivation requires various metabolic adaptations such as energy and protein sparing, which can be highly conflicting with energy-demanding stages of an animals life history such as growth. 2.Due to the maternal attendance pattern, subantarctic fur seal (Arctocephalus tropicalis Gray) pups must repeatedly endure exceptionally long fasts of increasing duration throughout the 10-month lactation period. Little is known of (i) how these infants adapt to such extreme energetic constraints while sustaining growth and development; and (ii) the ecological implications of repeated prolonged fasting in early life in terms of offspring survival, maternal care and growth strategy in this species, as well as the evolutionary consequences of such life history trait. 3.Physiological responses to prolonged fasting and how they change with development throughout the pre-weaning period were investigated. Results show that beginning with their first fast, subantarctic fur seal pups are able to mobilize lipid reserves preferentially while conserving protein stores in response to nutritional deprivation. As pup age, profound changes in energy expenditure allow the implementation of an efficient strategy of fat storage and lean body mass preservation, which proves highly adaptive in the face of the low maternal provisioning rates experienced. 4.Despite increasing fasting durations, pup mortality decreased markedly throughout the maternal dependence period. Consistent with predictions, field measurements indicate that fasting endurance, although limited in early life, increases up to durations of nearly 3 months with age. Results suggest that the maternal provisioning strategy could be constrained by these ontogenetic changes in pup fasting abilities. 5.Furthermore, extreme energetic constraints and local density-dependent effects appear to exert a strong selective pressure upon the adoption of a convergent growth strategy between the sexes aiming to maximize fat storage and pre-weaning survival. 6.The issues of resulting trade-offs between pre- and post-weaning survival and the evolutionary consequences of extreme fasting abilities are also addressed.
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Programme |
109 |
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Blackwell Publishing Ltd |
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1365-2435 |
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yes |
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Call Number |
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Serial |
1058 |
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Author |
Verrier Delphine, Atkinson Shannon, Guinet Christophe, Groscolas René, Arnould John P Y, |
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Title |
Hormonal responses to extreme fasting in subantarctic fur seal (Arctocephalus tropicalis) pups
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Type |
Journal Article |
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Year |
2012 |
Publication |
American Journal of Physiology – Regulatory, Integrative and Comparative Physiology |
Abbreviated Journal |
Am. J. Physiol. Regul. Integr. Comp. Physiol. |
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Volume |
302 |
Issue |
8 |
Pages |
R929 -R940 |
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Keywords |
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Abstract |
Surviving prolonged fasting implies closely regulated alterations in fuel provisioning to meet metabolic requirements, while preserving homeostasis. Little is known, however, of the endocrine regulations governing such metabolic adaptations in naturally fasting free-ranging animals. The hormonal responses to natural prolonged fasting and how they correlate to the metabolic adaptations observed, were investigated in subantarctic fur seal (Arctocephalus tropicalis) pups, which, because of the intermittent pattern of maternal attendance, repeatedly endure exceptionally long fasting episodes throughout their development (13 mo). Phase I fasting was characterized by a dramatic decrease in plasma insulin, glucagon, leptin, and total l-thyroxine (T4) associated with reductions in mass-specific resting metabolic rate (RMR), plasma triglycerides, glycerol, and urea-to-creatine ratio, while nonesterified fatty acids (NEFA) and -OHB increased. In contrast, the metabolic steady-state of phase II fasting reached within 6 days was associated with minimal concentrations of insulin, glucagon, and leptin; unchanged cortisol and triiodothyronine (T3); and moderately increased T4. The early fall in insulin and leptin may mediate the shift to the strategy of energy conservation, protein sparing, and primary reliance on body lipids observed in response to the cessation of feeding. In contrast to the typical mammalian starvation response, nonelevated cortisol and minimal glucagon levels may contribute to body protein preservation and downregulation of catabolic pathways, in general. Furthermore, thyroid hormones may be involved in a process of energy conservation, independent of pups' nutritional state. These original hormonal settings might reflect an adaptation to the otariid repeated fasting pattern and emphasize the crucial importance of a tight physiological control over metabolism to survive extreme energetic constraints.
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109 |
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0363-6119 |
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yes |
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Call Number |
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Serial |
3904 |
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| Permanent link to this record |
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Author |
Verrier Delphine, Atkinson Shannon, Guinet Christophe, Groscolas René, Arnould John P Y, |
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Title |
Hormonal responses to extreme fasting in subantarctic fur seal (Arctocephalus tropicalis) pups
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Type |
Journal Article |
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Year |
2012 |
Publication |
American Journal of Physiology – Regulatory, Integrative and Comparative Physiology |
Abbreviated Journal |
Am. J. Physiol. Regul. Integr. Comp. Physiol. |
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Volume |
302 |
Issue |
8 |
Pages |
R929 -R940 |
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Keywords |
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Abstract |
Surviving prolonged fasting implies closely regulated alterations in fuel provisioning to meet metabolic requirements, while preserving homeostasis. Little is known, however, of the endocrine regulations governing such metabolic adaptations in naturally fasting free-ranging animals. The hormonal responses to natural prolonged fasting and how they correlate to the metabolic adaptations observed, were investigated in subantarctic fur seal (Arctocephalus tropicalis) pups, which, because of the intermittent pattern of maternal attendance, repeatedly endure exceptionally long fasting episodes throughout their development (13 mo). Phase I fasting was characterized by a dramatic decrease in plasma insulin, glucagon, leptin, and total l-thyroxine (T4) associated with reductions in mass-specific resting metabolic rate (RMR), plasma triglycerides, glycerol, and urea-to-creatine ratio, while nonesterified fatty acids (NEFA) and -OHB increased. In contrast, the metabolic steady-state of phase II fasting reached within 6 days was associated with minimal concentrations of insulin, glucagon, and leptin; unchanged cortisol and triiodothyronine (T3); and moderately increased T4. The early fall in insulin and leptin may mediate the shift to the strategy of energy conservation, protein sparing, and primary reliance on body lipids observed in response to the cessation of feeding. In contrast to the typical mammalian starvation response, nonelevated cortisol and minimal glucagon levels may contribute to body protein preservation and downregulation of catabolic pathways, in general. Furthermore, thyroid hormones may be involved in a process of energy conservation, independent of pups' nutritional state. These original hormonal settings might reflect an adaptation to the otariid repeated fasting pattern and emphasize the crucial importance of a tight physiological control over metabolism to survive extreme energetic constraints.
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Programme |
119 |
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0363-6119 |
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yes |
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Call Number |
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Serial |
4186 |
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Author |
Verrier D., Groscolas R., Guinet C. & Arnould J. |
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Title |
Ontogeny of extreme fasting abilities in subantarctic fur seal pups: importance of metabolic rates and body lipid reserves. |
Type |
Conference - International - Poster |
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Year |
2006 |
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Abstract |
52nd Scientific Meeting of the Australian Mammal Society, July 3-5, 2006, Melbourne, Australie (Lyne Award pour meilleur poster) |
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119 |
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yes |
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Call Number |
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Serial |
3285 |
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Author |
Verrier D., Arnould J., Groscolas R. & Guinet C. |
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Title |
Ontogeny of extreme fasting abilities in subantarctic fur seal (Arctocephalus tropicalis)pups. |
Type |
Conference - International - Communication |
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Year |
2005 |
Publication |
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Abstract |
16th Biennal Conference on the Biology of Marine Mammals, 12-16 décembre 2005, San Diego, USA |
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119 |
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yes |
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Call Number |
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Serial |
3290 |
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Author |
VERREAULT J., VERBOVEN N., GABRIELSEN G., LETCHER R.J., CHASTEL O. |
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Title |
Changes in prolactin in a highly organohalogen contaminated Arctic top predator seabird, the glaucous gull. |
Type |
Journal Article |
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Year |
2008 |
Publication |
GENERAL AND COMPARATIVE ENDOCRINOLOGY |
Abbreviated Journal |
Gen. Comp. Endocrinol. |
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Volume |
156 |
Issue |
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Pages |
569-576 |
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Abstract |
The factors influencing prolactin (PRL) variation in birds and in wildlife in general have rarely been investigated with respect to the physiological impacts of exposure to environmental contaminants. We investigated the associations between circulating baseline PRL levels and concentrations of eight persistent organohalogen contaminant (OHC) classes (i.e., major organochlorines and brominated flame retardants, and associated metabolic products) in blood (plasma) of free-ranging glaucous gulls (Larus hyperboreus), a top predator in the Norwegian Arctic, engaged in the process of incubation. We further examined whether plasma OHC concentrations were associated with the variation of PRL in glaucous gulls exposed to a standardized capture/restraint protocol. Plasma OHC concentrations in male glaucous gulls were 2-to 3-fold higher relative to females. Baseline PRL levels tended to be higher in females compared to males, although not significantly (p = 0.20). In both males and females, the 30-min capture/restraint protocol led on average to a 26% decrease in PRL levels, which resulted in a rate of PRL decrease of 0.76 ng/mL/min. The baseline PRL levels and the rate of decrease in PRL levels tended to vary negatively with plasma OHC concentrations in males, but not in females, although several of these associations did not adhere with the criterion of significance (a = 0.05). Present results suggest that in highly OHC-exposed male glaucous gulls, the control of PRL release may be affected by the direct or indirect modulating actions of OHCs and/or their metabolically derived products. We conclude that potentially OHC-mediated impact on PRL secretion in glaucous gulls (males) may be a contributing factor to the adverse effects observed on the reproductive behavior, development and population size of glaucous gulls breeding in the Norwegian Arctic. |
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330 |
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0016-6480 |
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Approved |
yes |
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Serial |
6004 |
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Author |
Véronique Van Tilbeurgh, Anne Atlan |
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Title |
Pluralité des valeurs attribuées à la nature : le rôle des instances de socialisation primaire |
Type |
Journal |
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Year |
2022 |
Publication |
VertigO – la revue électronique en sciences de l'environnement |
Abbreviated Journal |
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Volume |
22 |
Issue |
3 |
Pages |
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Keywords |
îles subantarctiques instance de socialisation socialisation primaire valeurs de la nature |
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Abstract |
Alors qu’il existe une grande diversité de valeurs attribuées à la nature, les déterminants sociaux habituels, tels que la catégorie socio-professionnelle, l’âge ou le sexe, se sont avérés peu explicatifs. Cet article explore le rôle de la socialisation, et plus particulièrement de la socialisation primaire dans le type de valeur que les individus affectent à la nature. L’enquête s’est déroulée dans les îles subantarctiques, choisies car la nature y est valorisée dans un contexte non-utilitariste et non-marchand, ce qui permet l’expression d’un grand nombre de valeurs. Nous avons analysé les correspondances entre les formes de socialisation des individus à la nature et les valeurs qu’ils lui affectent. La principale distinction met en tension deux instances de socialisation primaire : au sein de la famille et par les groupes de pairs. Les premières conduisent à une évaluation de la nature suivant un principe dominant et abstrait, les secondes à une évaluation égalitaire et concrète. En revanche, ceux qui n’ont pas été socialisés à la nature durant l’enfance ont plutôt tendance à mettre en avant la valorisation d’eux-mêmes acquise par l’expérience de nature. Si les trajectoires linéaires sont largement majoritaires, des renforcements ou des altérations sont possibles, montrant que certaines formes de socialisation secondaire peuvent faire ou évoluer les valeurs attribuées à la nature. |
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136 |
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1492-8442 |
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yes |
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8547 |
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Author |
Vernon P., Vannier G. & Trehen P. |
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Title |
A comparative approach to the entomological diversity of polar regions. |
Type |
Journal Article |
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Year |
1998 |
Publication |
Acta oecologica-international journal of ecology |
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19(3) |
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303-308 |
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136 |
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ISSN |
1146-609X |
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yes |
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79 |
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Author |
Vernon P., Caron F. & Trehen P. |
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Title |
How to measure variability in some parameters of Ecophysiological interest: a case study. |
Type |
Conference - International - Article without Reading Comitee |
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Year |
1992 |
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35 |
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Abstract |
First European Workshop on invertebrate Ecophysiology |
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136 |
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yes |
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Call Number |
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Serial |
383 |
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