Relationships between plasma ketones and fasting duration in neonatal elephant seals

1990 ◽  
Vol 259 (5) ◽  
pp. R1086-R1089 ◽  
Author(s):  
M. A. Castellini ◽  
D. P. Costa
Keyword(s):  
Ketone Bodies ◽  
Elephant Seal ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Long Duration ◽  
Fat Stores ◽  
Low Levels ◽  
Beta Hydroxybutyrate ◽  
Fasting Duration ◽  
Circulating Levels

Long-duration fasting in mammals can ultimately lead to stage three terminal starvation, which is characterized by depleted fat stores, a metabolic shift away from fat metabolism toward lean tissue catabolism, and a sharp decline in circulating levels of plasma fatty acids and ketone bodies. However, this biochemical shift has never been observed outside of the laboratory in a naturally fasting, nonhibernating mammal. In the current study, plasma levels of the ketone body D-beta-hydroxybutyrate (beta-HBA) were assayed in 10 Northern elephant seal pups during suckling and the postweaning fast and in 12 fasting adult seals. Plasma beta-HBA concentration in the pups was minimal during suckling (0.09 +/- 0.06 mM; n = 10) and began to increase immediately after weaning. The concentration rose until about 55 days into the fast (1.34 +/- 0.36 mM; n = 10) and then declined sharply. Within 10 days of this deflection point, the seal pups left for sea. By contrast, adult elephant seals showed consistently low levels of beta-HBA after several months of fasting (0.06 +/- 0.07 mM; n = 12). The data suggest that the duration of fasting in elephant seal pups may be determined, in part, by biochemical shifts that occur near the end of the fast and that the regulation of ketone concentration is different in fasting neonatal and adult elephant seals.

Aggression in the Female Northern Elephant Seal, Mirounga Angustirostris

Behaviour ◽  
1978 ◽  
Vol 64 (1-2) ◽  
pp. 158-171 ◽  
Author(s):  
T.E. Christenson ◽  
B.J. Le Boeuf
Keyword(s):  
Reproductive Success ◽  
Aggressive Behavior ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Advantages And Disadvantages ◽  
Northern Elephant Seals ◽  
Pup Survival ◽  
Male Activity

AbstractMaternal aggressive behavior of northern elephant seals enhances reproductive success by increasing the likelihood of pup survival. Detailed observations of marked mother-pup pairs revealed that female aggressiveness increased dramatically after giving birth. Maternal aggressiveness also correlated negatively with the number of times the pup was bitten by alien females. Mothers of these pups were less aggressive than the 17 whose pups survived. Pup behavior was not directly related to mortality. Frequencies of interfemale aggressive encounters were compared for different beach areas. Aggression was most frequent on the smallest area, where interfemale distance was the shortest, and tidal action extreme. Aggression was least frequent on the sparcely populated beach, affected little by tide or male activity. Interfemale distance was greatest here. Reproductive advantages and disadvantages of pupping on each area are noted.

Diving behavior in relation to ambient water temperature in northern elephant seals

1994 ◽  
Vol 72 (4) ◽  
pp. 643-651 ◽  
Author(s):  
Hiroshi Hakoyama ◽  
Burney J. Le Boeuf ◽  
Yasuhiko Naito ◽  
Wataru Sakamoto
Keyword(s):  
Water Temperature ◽  
Elephant Seal ◽  
Diving Behavior ◽  
Mirounga Angustirostris ◽  
Ambient Water ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Abrupt Changes ◽  
Ambient Water Temperature

Our aim was to describe changes in ambient water temperature during the course of migration by northern elephant seals (Mirounga angustirostris) and to examine evidence for the seal using abrupt temperature gradients for locating prey. During migration in the post breeding season, the diving patterns of 10 adult females and 7 breeding-age males from Año Nuevo, California, were recorded with time–depth recorders in 1989–1991. Recorded sea surface temperatures declined from 11–13 °C to a low of 3–9 °C as the seals moved north and increased as they returned. Depth of diving was not closely linked to sharp thermal gradients. A thermocline was evident only at the beginning and end of the migration in less than 100 m of water, where less than 2% of diving takes place. There were sex differences in the temperature range at the depths where 75% of diving and foraging occurred, owing in part to habitat separation. The temperatures were lower and the range narrower for females (4.2–5.2 °C at 388–622 m) than for males (5.3–6.0 °C at 179–439 m). We conclude that the northern elephant seal habitat does not provide abrupt changes in temperature that might serve as important cues for locating prey.

Blood viscosity and optimal hematocrit in a deep-diving mammal, the northern elephant seal (Mirounga angustirostris)

1986 ◽  
Vol 64 (10) ◽  
pp. 2081-2085 ◽  
Author(s):  
Michael S. Hedrick ◽  
Deborah A. Duffield ◽  
Lanny H. Cornell
Keyword(s):  
Oxygen Transport ◽  
Blood Viscosity ◽  
Storage Capacity ◽  
Oxygen Storage Capacity ◽  
Elephant Seal ◽  
Oxygen Storage ◽  
Diving Behavior ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Deep Diving

Elephant seals offer a unique opportunity to examine rheological characteristics of blood because of the normally high hematocrits in this species. A comparison of blood viscosity of the elephant seal with that of a terrestrial mammal (rabbit; HCT = 35%) reveals a threefold increase in viscosity of elephant seal blood over that of rabbit blood due to the high hematocrit (HCT = 65%). While the increased hematocrit of elephant seal blood reflects increased oxygen storage capacity, blood oxygen transport may actually be reduced by the effects of increased blood viscosity on blood flow. Elephant seal plasma viscosity was also higher than that of rabbit plasma; this was associated with a higher concentration of plasma proteins. There were no apparent differences in the viscous properties of the red blood cells of the two species. The theoretically optimal hematocrit was determined in vitro for reconstituted blood from each species and compared with the observed in vivo hematocrit. It was found that the observed hematocrit of the elephant seal lies far to the right of the predicted hematocrit for optimal oxygen transport, while the rabbit hematocrit was identical with the predicted value. These results suggest that elephant seals have increased oxygen storage capacity at the expense of optimizing oxygen transport. The observed increase in hematocrit and viscosity may be of importance in considering the diving behavior and energetics of elephant seals.

scholarly journals Oxylipin Responses to Fasting and Insulin Infusion in a Large Mammalian Model of Fasting-Induced Insulin Resistance, the Northern Elephant Seal

2021 ◽  
Author(s):  
Dana N. Wright ◽  
Kondwani G.H. Katundu ◽  
Jose A. Viscarra ◽  
Daniel E. Crocker ◽  
John W. Newman ◽  
...  
Keyword(s):  
Insulin Resistance ◽  
Lipid Metabolism ◽  
Metabolic Regulation ◽  
Insulin Infusion ◽  
Area Under The Curve ◽  
Elephant Seal ◽  
Bioactive Metabolites ◽  
Northern Elephant Seal ◽  
Post Infusion ◽  
Fasting Duration

The prolonged, post-weaning fast of northern elephant seal (Mirounga angustirostris) pups is characterized by a reliance on lipid metabolism and reversible, fasting-induced insulin resistance providing a unique model to examine the effects of insulin on lipid metabolism. We have previously shown that acute insulin infusion induced a shift in fatty acid metabolism dependent on fasting duration. This study complements the previous study by examining the effects of fasting duration and insulin infusion on circulating levels of oxylipins, bioactive metabolites derived from the oxygenation of polyunsaturated fatty acids. Northern elephant seal pups were studied at two post-weaning periods (n = 5/period): early fasting (1-2 weeks post-weaning; 127 ± 1 kg) and late fasting (6-7 weeks post-weaning; 93 ± 4 kg). Different cohorts of pups were weighed, sedated, and infused with 65 mU/kg of insulin. Plasma was collected prior to infusion (T0), and at 10, 30, 60, and 120 min post-infusion. A profile of ~80 oxylipins were analyzed by UPLC-ESI-MS/MS. Nine oxylipins changed between early and late fasting and eight were altered in response to insulin infusion. Fasting decreased PGF2a and increased 14,15-DiHETrE, 20-HETE, and 4-HDoHE (p<0.03) in T0 samples, while insulin infusion resulted in an inverse change in area under the curve (AUC) levels in these same metabolites (p<0.05). In addition, 12-HpETE and 12-HETE decreased with fasting and insulin infusion, respectively (p<0.04). The oxylipins altered during fasting and in response to insulin infusion may contribute to the manifestation of insulin resistance and participate in the metabolic regulation of associated cellular processes.

scholarly journals Treatment of Canine Tooth Fractures in the Northern Elephant Seal (Mirounga angustirostris): Three Cases

2019 ◽  
Vol 36 (1) ◽  
pp. 52-61
Author(s):  
Deborah L. Hodesson ◽  
Judy Force ◽  
Sophie Whoriskey ◽  
Cara Field
Keyword(s):  
Maternal Separation ◽  
Case Series ◽  
Elephant Seal ◽  
Anthropogenic Factors ◽  
Mirounga Angustirostris ◽  
Canine Tooth ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Northern Elephant Seals ◽  
Pulp Exposure

The Marine Mammal Center (TMMC) in Sausalito, California, rescues, rehabilitates, and releases hundreds of stranded northern elephant seals ( Mirounga angustirostris) each year. Common causes for stranding include maternal separation, malnutrition, and trauma. Causes of trauma include shark bites, conspecific interactions, and anthropogenic factors. Several cases of fractured teeth, secondary to presumed trauma, are presented to the center each year. This case series describes surgical approach and treatment of 3 young northern elephant seals that were admitted to TMMC for rehabilitation with tooth fractures with pulp exposure of maxillary or mandibular canine teeth. All 3 seals were successfully released into their natural environment.

Effects of prolonged fasting on plasma cortisol and TH in postweaned northern elephant seal pups

2001 ◽  
Vol 280 (3) ◽  
pp. R790-R795 ◽  
Author(s):  
Rudy M. Ortiz ◽  
Charles E. Wade ◽  
C. Leo Ortiz
Keyword(s):  
Fat Metabolism ◽  
Plasma Concentrations ◽  
Primary Source ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Hormone Metabolism ◽  
Northern Elephant Seal ◽  
Fasting Period ◽  
Total Triiodothyronine ◽  
Fat Stores

Northern elephant seal ( Mirounga angustirostris) pups rely on the oxidation of fat stores as their primary source of energy during their 8- to 12-wk postweaning fast; however, potential endocrine mechanisms involved with this increased fat metabolism have yet to be examined. Therefore, 15 pups were serially blood sampled in the field during the first 7 wk of their postweaning fast to examine the changes in plasma concentrations of cortisol and thyroid hormones (TH), which are involved in fat metabolism in other mammals. Cortisol increased, indicating that it contributed to an increase in lipolysis. Increased total triiodothyronine (tT3) and thyroxine (tT4) may not reflect increased thyroid gland activity, but rather alterations in hormone metabolism. tT3-to-tT4 ratio decreased, suggesting a decrease in thyroxine (T4) deiodination, whereas the negative correlation between total proteins and free T4 suggests that the increase in free hormone is attributed to a decrease in binding globulins. Changes in TH are most similar to those observed during hibernation than starvation in mammals, suggesting that the metabolic adaptations to natural fasting are more similar to hibernation despite the fact these animals remain active throughout the fasting period.

scholarly journals Creation Nerves of the Lumbar and Sacral Plexus in California Sea Lions (Zalophus Californianus) and Northern Elephant Seals (Mirounga Angustirostris)/Formiranje Nerava Iz Lumbalnog I Sakralnog Pleksusa Kod Kalifornijskog Morskog Lava (Zalophus Californianus) I Severnomorskog Slona (Mirounga Angustirostris)

2014 ◽  
Vol 64 (3) ◽  
pp. 293-306 ◽  
Author(s):  
Mihelić Damir ◽  
Smodlaka Hrvoje ◽  
Tkalčić Suzana ◽  
Palmer Lauren ◽  
Mršić Gordan ◽  
...  
Keyword(s):  
Femoral Nerve ◽  
Elephant Seal ◽  
Zalophus Californianus ◽  
Mirounga Angustirostris ◽  
California Sea Lions ◽  
Northern Elephant Seal ◽  
Elephant Seals ◽  
Sea Lions ◽  
Northern Elephant Seals ◽  
Sacral Nerves

Abstract The lumbosacral plexus was investigated in the California sea lion and Northern elephant seal. In 9 California sea lions and 2 Northern elephant seals the femoral nerve rises from the ventral branches of the 3rd and 4th lumbar nerves, whilst in one male and two specimens of the Northern elephant seal the 5th lumbar nerve was also involved. Ventral branches of the 3rd and 4th lumbar nerves comprised the obturatorius nerve in 7 specimens; in 3 specimens the 5th lumbar nerve additionally supplements the obturatorius nerve. In Northern elephant seals the obturatorius nerve originates from the ventral branches of the 3rd, 4th and 5th lumbar nerves. The ischiadic nerve originates from the ventral branches of the 4th, 5th lumbar and 1st sacral nerves in 8 specimens California sea lions and in 2 North elephant seals. In 2 specimens of both species the 2nd sacral nerve also participates. The gluteal nerve created ventral branches of the 5th lumbar and 1st sacral nerves in three specimens; however in one specimen the 4th and 5th lumbar nerves gave rise to the same nerve in the Northern elephant seal. In California sea lions the gluteal nerve originates from the ventral branches of the 5th lumbar nerve in seven specimens, nonetheless in 3 specimens the 4th lumbar nerve also participates in its formation.

scholarly journals GH and ghrelin increase with fasting in a naturally adapted species, the northern elephant seal (Mirounga angustirostris)

2003 ◽  
Vol 178 (3) ◽  
pp. 533-539 ◽  
Author(s):  
RM Ortiz ◽  
DP Noren ◽  
CL Ortiz ◽  
F Talamantes
Keyword(s):  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Prolonged Fasting ◽  
Northern Elephant Seal ◽  
Factor I ◽  
Esterified Fatty Acids ◽  
Igf I ◽  
Fat Stores ◽  
The Relationship ◽  
Natural Component

After nursing, pups of the northern elephant seal (Mirounga angustirostris) are approximately 46% body fat and rely almost entirely on the oxidation of their large fat stores to sustain their metabolism for the ensuing 8-12 week postweaning fast, which is a natural component of their life history. Thus, fasting pups provide an ideal opportunity to examine the hormonal alterations associated with prolonged food deprivation in a naturally adapted model. Cortisol, ghrelin, glucagon, growth hormone (GH), insulin-like growth factor-I (IGF-I), insulin, blood urea nitrogen (BUN), glucose and non-esterified fatty acids (NEFA) were examined in 20 male and 20 female pups blood sampled early (<1 week postweaning) and late (6-8 weeks postweaning) during the fast. Mean cortisol, ghrelin, GH, and glucagon increased 1.8-, 1.8-, 1.4-, and 2.3-fold between early and late periods, while mean IGF-I and insulin decreased 97% and 38%, respectively. NEFA increased 2.3-fold, while BUN and glucose decreased 46% and 11%, respectively. NEFA was significantly and positively correlated with cortisol and GH; individually; however, when the relationship was examined as a multiple regression the correlation improved suggesting that cortisol and GH act synergistically to promote lipolysis during the fast. GH and BUN were negatively and significantly correlated between early and late fasting suggesting that GH may promote protein sparing as well. The decrease in glucose may be responsible for stimulating glucagon, resulting in the maintenance of relative hyperglycemia. The increases in cortisol, ghrelin, glucagon, and GH suggest that these hormones may be integral in mediating the metabolism of seal pups during prolonged fasting.

A new perspective on adiposity in a naturally obese mammal

2001 ◽  
Vol 281 (6) ◽  
pp. E1347-E1351 ◽  
Author(s):  
Rudy M. Ortiz ◽  
Dawn P. Noren ◽  
Beate Litz ◽  
C. Leo Ortiz
Keyword(s):  
Body Fat ◽  
Marine Mammals ◽  
Tritiated Water ◽  
Elephant Seal ◽  
Mirounga Angustirostris ◽  
Prolonged Fasting ◽  
Northern Elephant Seal ◽  
Fat Stores ◽  
New Perspective ◽  
Water Dilution

Many mammals seasonally reduce body fat due to inherent periods of fasting, which is associated with decreased leptin concentrations. However, no data exist on the correlation between fat mass (FM) and circulating leptin in marine mammals, which have evolved large fat stores as part of their adaptation to periods of prolonged fasting. Therefore, FM was estimated (by tritiated water dilution), and serum leptin and cortisol were measured in 40 northern elephant seal ( Mirounga angustirostris) pups early (<1 wk postweaning) and late (6–8 wk postweaning) during their natural, postweaning fast. Body mass (BM) and FM were reduced late; however, percent FM (early: 43.9 ± 0.5, late: 45.5 ± 0.5%) and leptin [early: 2.9 ± 0.1 ng/ml human equivalents (HE), late: 3.0 ± 0.1 ng/ml HE] did not change. Cortisol increased between early (9.2 ± 0.5 μg/dl) and late (16.3 ± 0.9 μg/dl) periods and was significantly and negatively correlated with BM ( r = 0.426; P < 0.0001) and FM ( r = 0.328; P = 0.003). FM and percent FM were not correlated ( P > 0.10) with leptin at either period. The present study suggests that these naturally obese mammals appear to possess a novel cascade for regulating body fat that includes cortisol. The lack of a correlation between leptin and FM may reflect the different functions of fat between terrestrial and marine mammals.

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