Health status of young Alaska Steller sea lion pups (Eumetopias jubatus) as indicated by blood chemistry and hematology

Blood chemistry and hematology were examined in 238 Steller sea lion pups (Eumetopias jubatus) to assess the health status of pups <1 month of age. Failure of juvenile recruitment (possibly due to nutritionally or physiologically compromised pups) into breeding populations has been proposed as a cause of recent declines of this endangered species in Alaska. To identify potential correlations with areas of high population decline, blood chemistry data were considered for three areas: eastern Aleutian Islands (low rates of population decline to stable populations), Gulf of Alaska (high rates of decline), and Southeast Alaska (stable to increasing population). Southeast Alaska pups showed elevated ketone body concentrations (beta-hydroxybutyrate,(beta-HBA)) and depressed glucose levels than pups in the Gulf of Alaska. Over 40% of the pups from Southeast Alaska had elevated beta-HBA concentrations suggesting they underwent longer periods of fasting than seen in pups from other areas. Hematocrit (Hct), hemoglobin concentration (Hb) and water content of the blood exhibited typical mammalian relationships. In summary, blood chemistry and hematology data showed no indication that Steller sea lion pups <1 month old from areas of population decline were nutritionally compromised.     

Health status of young Alaska Steller sea lion pups (Eumetopias jubatus) as indicated by blood chemistry and hematology

Blood chemistry and hematology were examined in 238 Steller sea lion pups (Eumetopias jubatus) to assess the health status of pups <1 month of age. Failure of juvenile recruitment (possibly due to nutritionally or physiologically compromised pups) into breeding populations has been proposed as a cause of recent declines of this endangered species in Alaska. To identify potential correlations with areas of high population decline, blood chemistry data were considered for three areas: eastern Aleutian Islands (low rates of population decline to stable populations), Gulf of Alaska (high rates of decline), and Southeast Alaska (stable to increasing population). Southeast Alaska pups showed elevated ketone body concentrations (β-hydroxybutyrate, (β-HBA)) and depressed glucose levels when compared with animals from the Aleutian Islands and lower blood urea nitrogen (BUN) and glucose levels than pups in the Gulf of Alaska. Over 40% of the pups from Southeast Alaska had elevated β-HBA concentrations suggesting they underwent longer periods of fasting than seen in pups from other areas. Hematocrit (Hct), hemoglobin concentration (Hb) and water content of the blood exhibited typical mammalian relationships. In summary, blood chemistry and hematology data showed no indication that Steller sea lion pups <1 month old from areas of population decline were nutritionally compromised.     

Fasting metabolism in Antarctic fur seal (Arctocephalus gazella) pups.

The metabolism of 52-73-day old Antarctic fur seal pups from Bird Island, South Georgia, was investigated during fasting periods of normal duration while their mothers were at sea foraging. Body mass decreased exponentially with pups losing 3.5-3.8% of body mass per day. Resting metabolic rate also decreased exponentially from 172-197 ml (O2) x min(-1) at the beginning of the fast and scaled to M(b)(0.74) at 2.3 times the level predicted for adult terrestrial mammals of similar size. While there was no significant sex difference in RMR, female pups had significantly higher (F(1,18)=6.614, P<0.019) mass-specific RMR than male pups throughout the fasting period. Fasting FMR was also significantly (t(15)=2.37, P<0.035) greater in females (823 kJ x kg(-1) x d(-1)) than males (686 kJ x kg(-1) x d(-1)). Average protein turnover during the study period was 19.3 g x d(-1) and contributed to 5.4% of total energy expenditure, indicating the adoption of a protein-sparing strategy with a reliance on primarily lipid catabolism for metabolic energy. This is supported by observed decreases in plasma BUN, U/C, glucose and triglyceride concentrations, and an increase in beta-HBA concentration, indicating that Antarctic fur seals pups adopt this strategy within 2-3 days of fasting. Mean RQ also decreased from 0.77 to 0.72 within 3 days of fasting, further supporting a rapid commencement of protein-sparing. However, RQ gradually increased thereafter to 0.77, suggesting a resumption of protein catabolism which was not substantiated by changes in plasma metabolites. Female pups had higher TBL (%) than males for any given mass, which is consistent with previous findings in this and other fur seal species, and suggests sex differences in metabolic fuel use. The observed changes in plasma metabolites and protein turnover, however, do not support this.     

Extreme natal philopatry in female Antarctic fur seals (Arctocephalus gazella)

Natal philopatry is an important component of mammalian behaviour but is difficult to study in natural vertebrate populations due to the requirement for long-term individual-based spatial observations. Consequently, we quantified fine-scale patterns of natal philopatry in an intensively studied colony of Antarctic fur seals (Arctocephalus gazella), where a scaffold walkway allows individual locations to be measured to the nearest metre. Using subcutaneous PIT tags, we tracked the early life histories of 335 females born within the colony, of which 38 were resighted as breeding adults. We found that individual females returned to as little as one body length (2 m) of their birth locations. Moreover, distances between natal and pupping sites were not correlated with female age, but instead tended to decrease with the number of seasons an individual was sighted ashore. This suggests that breeding experience may be a better predictor than age of the ability of females to occupy preferred sites within fur seal colonies.     

Water conservation and protein metabolism in northern elephant seal pups during the postweaning fast

Urine production and N output were monitored in northern elephant seal (Mirounga angustirostris) pups progressing through 10 weeks of a natural postweaning fast. Urine output declind by 84% (to 69±12 ml·day^–1) at 10 weeks (P<0.05). Glomerular filtration rate at 10 weeks was 51% of the 67±3 ml serum·min^–1 observed during week 1 (P<0.05). Urine N excretion fell by 69% to 1.2±0.17 g·day^–1, while urinary concentration increased (P<0.05). Serum urea declined from an initial 11 mmol·1^–1 to 5–7 mmol·1^–1 by 5 weeks. The fall in urinary N loss (and thus amino acid oxidation) was concomitant with depressed metabolic rate. Therefore, protein contributed little toward meeting energy demands (i.e., <4% of average metabolic rate) throughout fasting. These data indicate that fasting pups improve water conservation and minimize protein catabolism during prolonged natural fasts without an exogenous source of water.Abbreviations AA amino acid(s) - AMR average metabolic rate - ANOVA one-way analysis of variance - BMR basal metabolic rate - BUN blood urea nitrogen - EP end product - EWL evaporative water loss - [Gr]_s serum creatinine concentration - GFR glomerular filtration rate - LBM lean body mass - LML Long Marine Laboratory - MR metabolic rate - NEFA non-esterified fatty acids - RMR resting metabolic rate - TCA tricarboxylic acid - U:C ulinary urea: creatinine concentration ratio     

The complete primary structure of the marine carnivora, galapagoes fur seal (Arctocephalus galapagoensis, Otariidae) hemoglobins

The complete primary structure of the two hemoglobin components of the fur seal (Arctocephalus galapagoensis) is presented. The two components (HbI and HbII) occur in nearly equal amounts and have identical -chains; whereas the two -chains (I/II) differ by six exchanges Ile/Val, Met/Thr, Ser/Ala, Pro/His, Lys/Gly, and Thr/Ala at positions 10, 34, 35, 50, 78, and 131, respectively. The components were isolated by DEAE-Sephacel chromatography and were separated into the globin chains by RP-HPLC on a column of Nucleocil-C4. The sequences have been determined by Edman degradation in liquid- and gas-phase sequencer, using the native chains and tryptic peptides. The sequences compared with those of other Carnivora species and an adult human globin chains. An identical -chain is found in fur seal and walrus, whereas larger differences were found between I and II compared to -chains.Deceased on May 27, 1989.     

Ontogeny of aquatic behaviours in Antarctic fur seal (Arctocephalus gazella) pups in relation to growth performances at Kerguelen Islands

In diving marine predators, such as pinnipeds, the development of diving and foraging skills prior to weaning might be critical to post-weaning survival. Here, we examined the effect of pup mass growth on the amount of time devoted to aquatic activities and the dive performance of Antarctic fur seal, Arctocephalus gazella, pups on Kerguelen Island. Maternal attendance and mass-specific growth rate were assessed for 85 pups. Two types of monitoring were applied: visual observations of behaviours for 60 pups and the deployment of time-depth recorders (TDRs) on 19 female pups. At approximately 2 months of age, pups demonstrated minimal diving behaviour, but displayed considerable aquatic activity. While mothers were foraging at sea, pups fasted on land (6.0 ± 1.3 d). As the mass-specific growth rate was different between sexes, only data on female pups were analysed (n = 31). Mass-specific growth rate was related to maternal attendance patterns and impacted the amount of time allocated by pups to aquatic activities. The time spent in the water by pups was quadratically related to fasting progress. This study shows the importance of growth and fasting progress on the quantity of time pups devoted to aquatic activities. Our results suggest that greater post-weaning survival of heavier pups may be due not only to their greater body reserves, as reported in several studies, but also possibly to from their greater aquatic skills and physiological adaptations developed during the suckling period.     

The influence of depth on a breath-hold diver: Predicting the diving metabolism of Steller sea lions (Eumetopias jubatus)

Diving animals must endeavor to increase their dive depths and prolong the time they spend exploiting resources at depth. Results from captive and wild studies suggest that many diving animals extend their foraging bouts by decreasing their metabolisms while submerged. We measured metabolic rates of Steller sea lions (Eumetopias jubatus) trained to dive to depth in the open ocean to investigate the relationships between diving behaviour and the energetic costs of diving. We also constructed a general linear model to predict the oxygen consumption of sea lions diving in the wild. The resultant model suggests that swimming distance and depth of dives significantly influence the oxygen consumption of diving Steller sea lions. The predictive power of the model was tested using a cross-validation approach, whereby models reconstructed using data from pairs of sea lions were found to accurately predict the oxygen consumption of the third diving animal. Predicted oxygen consumption during dives to depth ranged from 3.37 L min^− 1 at 10 m, to 1.40 L min^− 1 at 300 m over a standardized swimming distance of 600 m. This equated to an estimated metabolic rate of 97.54 and 40.52 MJ day^− 1, and an estimated daily feeding requirement of 18.92 and 7.96 kg day^− 1 for dives between 10 and 300 m, respectively. The model thereby provides information on the potential energetic consequences that alterations in foraging strategies due to changes in prey availability could have on wild populations of sea lions.     

Temporal changes in liver carbohydrate metabolism associated with seawater transfer in Oreochromis mossambicus

The metabolic aspects of ionic and osmotic regulation in fish are not well understood. The objective of this study was to examine changes in carbohydrate metabolism during seawater (SW) acclimation in the euryhaline tilapia (Oreochromis mossambicus). Hepatic activities of three key enzymes of the intermediary metabolism, phosphofructokinase, glycogen phosphorylase and glucose 6-phosphate dehydrogenase, together with glycogen content and plasma glucose concentration were measured at 0, 0.5, 1, 2, 3, 6, 12, 24, 48 and 96 h after the direct transfer of tilapia from fresh water (FW) to 70% SW. Plasma growth hormone, prolactin₁₇₇ and prolactin₁₈₈, Na⁺ and Cl⁻ concentrations were also measured. Plasma Na⁺ and Cl⁻ levels were highest at 12 h, but returned to FW levels at 24 h after transfer, suggesting the tilapia were able to osmoregulate within 24 h after transfer. Plasma glucose levels were significantly higher in 70% SW than in FW during the course of acclimation, especially in the early stages. Hepatic enzyme activities and glycogen content did not change significantly during the acclimation period. Our results suggest the possibility that glucose is an important energy source for osmoregulation during the acclimation to hyperosmotic environments in O. mossambicus.     

Enzymes of adenosine metabolism in Hymenolepis diminuta (Cestoda)

Gaitanaki C. and Beis I. 1985. Enzymes of adenosine metabolism in Hymenolepis diminuta (Cestoda). International Journal for Parasitology15: 651–654. The activities of 5-nucleotidase (E.C. 3.1.3.5), adenosine deaminase (E.C. 3.5.4.4), adenosine kinase (E.C. 2.7.1.20), AMP deaminase (E.C. 3.5.4.6) and adenylate kinase (E.C. 2.7.4.3) were demonstrated in homogenates of Hymenolepis diminuta. The K_m values for adenosine and AMP of the above enzymes were determined. The importance of these enzymes in the maintenance of adenosine concentration on a steady state in H. diminuta is discussed     

Enzyme‐linked immunosorbent assay to quantitate serum ferritin in the northern fur seal (Callorhinus ursinus)

Serum ferritin concentration correlates with tissue iron stores in humans, horses, calves, dogs, cats, and pigs. Serum ferritin is considered the best serum analyte to predict total body iron stores in these species, and is more reliable than serum iron or total iron‐binding capacity, both of which may be affected by disorders unrelated to iron adequacy or excess (including hypoproteinemia, chronic infection, hemolytic anemia, hypothyroidism, renal disease, and drug administration). Iron overload has been documented to result in hemochromatosis in captive northern fur seals (Callorhinus ursinus); therefore, we developed an enzyme‐linked immunosorbent assay (ELISA) to measure serum ferritin in this species. The assay uses two murine anti‐canine ferritin monoclonal antibodies in a sandwich arrangement that was originally used in an ELISA to measure serum ferritin in dogs. Ferritin isolated from fur seal liver was used as a standard. Ferritin standards were linear from 0 to 50 ng/ml. Recovery of purified ferritin from fur seal serum varied from 89% to 99%. The within‐assay variability was 6%, and the assay‐to‐assay variability for two different samples was 10% and 16%. Zoo Biol 23:79‐84, 2004.© 2004 Wiley‐Liss, Inc.     

Causes of mortality in South American fur seal pups (Arctophoca australis gracilis) at Guafo Island,southern Chile (2004–2008)

As part of population dynamics studies of the South American fur seal (Arctophoca australis gracilis) rookery at Punta Weather in Guafo Island (43°36'S, 74°43’W), the causes and extent of pup mortality were monitored. During four breeding seasons, daily counts of live and dead pups were carried out to determine pup production and pup mortality. Dead pups were retrieved from the rookery to perform necropsies. The mean pup production was 1,735.5 ± 336 pups and the mean pup mortality up to 12 wk old was 6.0%± 2.6%. The major causes of death were enteritis with microscopic lesions of bacteremia (28.4%), starvation (23.5%), drowning (21%), trauma (19.8%), and stillbirths (2.5%). Enteritis with microscopic lesions of bacteremia, and starvation had higher incidence during January (beginning and middle of the breeding season) while most trauma and drowning occurred during February (end of the breeding season). In the 2006–2007 breeding season there was an increase in mortality due to starvation and trauma. Most pup deaths at Guafo Island are generated by extrinsic factors; therefore, additional studies that assess the impact of environmental changes and fishing activities, are needed in order to determine the exact causes of the decline of this species along Chilean coasts.     

中华倒刺鲃能量代谢和热耐受特征的体重效应

为了探讨体重对中华倒刺鲃能量代谢和热耐受特征的影响,在25℃条件下分别测定不同体重大小(1、10、25、>50 g组)中华倒刺鲃的静止代谢率(Resting metabolic rate,RMR)、力竭运动后过量耗氧(Excess post-exercise oxygen consumption,EPOC)和热耐受参数。随体重的增加,中华倒刺鲃个体RMR、最大代谢率(Maximum metabolic rate,MMR)、代谢空间(Metabolic scope,MS)和EPOC均显著增加(P<0.05);单位体重RMR、MMR和MS则均显著降低,而单位体重EPOC随体重的增加显著增加(P<0.05)。RMR、MMR、MS和EPOC的代谢尺度指数分别为0.796、0.834、0.849和1.137且显著大于2/3,因此中华倒刺鲃的能量代谢参数均呈异速度增加的关系而变化。这些变化可能与其个体变大游泳运动能力增强导致能量代谢需求增加相关。中华倒刺鲃临界低温(Critical thermal minimum,CT_min)和致死低温(Lethal the...     

Fasting in the American marten (<Emphasis Type="Italic">Martes americana</Emphasis>): a physiological model of the adaptations of a lean-bodied animal

The American marten (Martes americana) is a boreal forest marten with low body adiposity throughout the year. The aim of this study was to investigate the adaptations of this lean-bodied species to fasting for an ecologically relevant duration (48 h) by exposing eight farm-bred animals to total food deprivation with seven control animals. Selected morphological and hematological parameters, plasma and serum biochemistry, endocrinological variables and liver and white adipose tissue (WAT) enzyme activities were determined. After 48 h without food, the marten were within phase II of fasting with depleted liver and muscle glycogen stores, but with active lipid mobilization indicated by the high lipase activities in several WAT depots. The plasma ghrelin concentrations were higher due to food deprivation, possibly increasing appetite and enhancing foraging behavior. The lower plasma insulin and higher cortisol concentrations could mediate augmented lipolysis and the lower triiodothyronine levels could suppress the metabolic rate. Fasting did not affect the plasma levels of stress-associated catecholamines or variables indicating tissue damage. In general, the adaptations to short-term fasting exhibited some differences compared to the related farm-bred American mink (Mustela vison), an example of which was the better ability of the marten to hydrolyze lipids despite its significantly lower initial fat mass.     

In vitro testing of anthelmintic efficacy of Flemingia vestita (Fabaceae) on carbohydrate metabolism in Rallietina echinobothrida

The root tuber peel of Flemingia vestita has been in use in local traditional medicine against intestinal worm infections in Meghalaya (North-East India). In order to evaluate and authenticate the anthelminitc efficacy of the isoflavones of F. vestita, the root peel extract of this putative plant was tested against several helminth parasites, extensively on Rallietina echinobothrida, with respect to different parameters of these parasites. In this paper, we describe various methods to evaluate the anthelmintic efficacy of this medicinal plant with respect to carbohydrate metabolism in R. echinobothrida at paralytic time caused by the isoflavones of F. vestita. To meet the high energy demand by the parasite due to the anthelmintic stress, glucose breakdown follows the PEPCK-malate pathway in the parasite.     

Changes in amino acids and protein metabolism in Egyptian cobra (Naja haje) during hibernation

1. 1.Total protein, GOT, GPT, alkaline phosphatase and total free amino acid content in the brain, liver and kidney were studied in the hibernating, arousing and normothermic cobra (Naja haje).

2. 2.Tissues showed a decline in protein content which started in the prehibernating animals. At the low body temperatures in hibernation both synthesis and degradation would be reduced. The fall in protein content suggests synthesis is reduced more steeply than is degradation. Recovery of protein biosynthesis was demonstrated during arousal.

3. 3.In aroused animals, the levels of free amino acids in the tissues examined were higher than in hibernating ones or in normothermic controls studied in summer.

4. 4.A decline in GOT activity was recorded in the hibernating animals. The enzyme activity showed recovery on arousal. A similar trend was observed for the GPT activity in brain and kidney.

5. 5.The activity of alkaline phosphatase was also examined in the different tissues. The correlation of these changes to the different phases of hibernating cycle is discussed.

Gas exchange and energy metabolism of the ostrich (Struthio camelus) embryo

We measured oxygen consumption ( ) and carbon dioxide emission ( ) rates, air-cell gas partial pressures of oxygen (P_AO₂) and CO₂ (P_ACO₂), eggshell water vapour conductance and energy content of the ostrich (Struthio camelus) egg, ‘true hatchling’ and residual yolk, and calculated RQ and total oxygen consumption ( ) for ostrich eggs incubated at 36.5°C and 25% relative humidity. The pattern showed a drop of approximately 5% before internal pipping. just prior to internal pipping agrees with allometric calculations. Despite the higher incubation temperature compared to other studies, and the resultant shorter incubation duration (42 days), (91.7 l kg⁻¹) was similar to a previously reported value. RQ values during the second half of incubation (approx. 0.68) were lower than expected for lipid catabolism. Prior to internal pipping, P_AO₂ and P_ACO₂ were 98 and 48.3 torr (13.1 and 6.4 kPa), respectively. The growth pattern of the ostrich embryo is different from the typical precocial pattern, showing a time delay in the rapid growth phase. As a result, the lowered overall energy expenditure for tissue maintenance, as compared to other species, is reflected in the low yolk utilization and high residual yolk fraction of the whole hatchling dry mass. These could also result from the relatively short incubation period of the ostrich egg, thereby evading desiccation by excess water loss.     

Energy metabolism and thermoregulation in pygmy lorises (Nycticebus pygmaeus) from Yunnan Daweishan Nature Reserve

The pygmy loris (Nycticebus pygmaeus) is a small prosimian living in Vietnam, Laos, eastern Cambodia and the south part of China. In China it is only found in Pingbian, Hekou, Jinping, Luchun of Yunnan. As N. pygmaeus is seriously threatened by hunting, trade and habitat destruction, it is listed in Appendix II of CITES, and in 2006 the IUCN classified it as “vulnerable”. In order to understand the characteristics of energy metabolism and thermoregulation of N. pygmaeus, the resting metabolic rate (RMR) and body temperature (T_b) at different ambient temperature (T_a) of pygmy lorises, as well as body mass, energy intake, digestable energy intake, digestability and the thermal conductance were measured in captivity. The results obtained mainly are as follows: (1) Pygmy loris feed dry food averaged 12.90 ± 1.02 g/d. They could gain 214.87 ± 16.65 kJ/d from food intake, and earned 200.15 ± 16.36 kJ digestable energy intake per day with 90.13 ± 1.34% of the digestability. (2) The T_b at room temperatures was a little low (35.23 ± 0.16 °C) and varied with T_a from 25 °C to 35 °C. There was a positive relationship between T_b and T_a, which was described as: T_b = 27.22 + 0.34T_a (r = 0.880). (3) The resting metabolic rate (RMR) of the pygmy loris was 0.3844 ± 0.0162 mlO₂/g/h, which was 51.91 ± 1.90% of the previous predicted rate by Kleiber (1961) [21]. (4) The average thermal conductance of the pygmy loris (N. pygmaeus) was 0.0449 ± 0.0031 mlO₂/g/h/°C. These characteristics of energy metabolism and thermoregulation of N. pygmaeus in Yunnan Daweishan Nature Reserve might be considered as the adaptive characteristics to their environment in tropical semi-evergreen forests and secondary forests.