Metabolic response of dolphins to short-term fasting reveals physiological changes that differ from the traditional fasting model

Bottlenose dolphins (Tursiops truncatus) typically feed on prey that are high in lipid and protein content and nearly devoid of carbohydrate, a dietary feature shared with other marine mammals. However, unlike fasted-adapted marine mammals that predictably incorporate fasting into their life history, dolphins feed intermittently throughout the day and are not believed to be fasting-adapted. To assess whether the physiological response to fasting in the dolphin shares features with or distinguishes them from those of fasting-adapted marine mammals, the plasma metabolomes of eight bottlenose dolphins were compared between post-absorptive and 24-hour fasted states. Increases in most identified free fatty acids and lipid metabolites and reductions in most amino acids and their metabolites were consistent with the upregulation of lipolysis and lipid oxidation and the downregulation of protein catabolism and synthesis. Consistent with a previously hypothesized diabetic-like fasting state, fasting was associated with elevated glucose and patterns of certain metabolites (e.g. citrate, cis-aconitate, myristoleic acid) indicative of lipid synthesis and glucose cycling to protect endogenous glucose from oxidative disposal. Pathway analysis predicted an upregulation of cytokines, decreased cell growth, and increased apoptosis including apoptosis of insulin-secreting β-cells. Metabolomic conditional mutual information networks were estimated for the post-absorptive and fasted states and ‘topological modules’ were estimated for each using the eigenvector approach to modularity network division. A Dynamic Network Marker indicative of a physiological shift toward a negative energy state was subsequently identified that has the potential conservation application of assessing energy state balance in at-risk wild dolphins.

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The Protection of Animals During Warfare

AJIL Unbound ◽

10.1017/aju.2017.69 ◽

2017 ◽

Vol 111 ◽

pp. 272-276

Author(s):

Jérôme de Hemptinne

Keyword(s):

Marine Mammals ◽

Bottlenose Dolphins ◽

Rapid Rate ◽

Human Beings ◽

Armed Groups ◽

Military Operations ◽

Protected Species ◽

California Sea Lions ◽

Animal Products ◽

Sea Lions

In times of war, the first instinct is to relieve the suffering of human beings. Environmental and animal interests are always pushed into the background. However, warfare strongly affects natural resources, including animals, which makes animal issues a matter of great concern. Certain species have been vanishing at a rapid rate because of wars, often with disastrous effects on the food chain and on the ecological balance. Indeed, belligerents rarely take into account the adverse consequences of their military operations on animals. They even take advantage of the chaotic circumstances of war in order to poach protected species and to engage in the trafficking of expensive animal products. While generating billions of dollars each year, such poaching and trafficking allows armed groups to grow and to reinforce their authority over disputed territory. States have also trained, and continue to train, certain animals—principally marine mammals such as bottlenose dolphins and California sea lions—to perform military tasks, like ship and harbor protection, or mine detection and clearance. Millions of horses, mules, donkeys, camels, dogs, and birds are obliged to serve on various fronts (transport, logistics, or communications) and become particularly vulnerable targets.

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Cetacean Research and Citizen Science in Kenya

Frontiers in Marine Science ◽

10.3389/fmars.2021.642399 ◽

2021 ◽

Vol 8 ◽

Author(s):

Michael Gilbert Mwango’mbe ◽

Jane Spilsbury ◽

Steve Trott ◽

Judith Nyunja ◽

Nina Wambiji ◽

...

Keyword(s):

Citizen Science ◽

Marine Mammal ◽

Marine Mammals ◽

Bottlenose Dolphins ◽

Conservation Strategies ◽

Science Data ◽

Pilot Whale ◽

Area Of Interest ◽

Mammal Conservation ◽

Kenyan Coast

In 2011, several non-governmental and government agencies established the Kenya Marine Mammal Network (KMMN) to provide a platform for the consistent collection of data on marine mammals along the Kenyan coast, identify areas of importance and engage marine users and the general public in marine mammal conservation. Prior to the KMMN, relatively little was known about marine mammals in Kenya, limiting conservation strategies. The KMMN collects data nationwide through dedicated surveys, opportunistic sightings and participative citizen science, currently involving more than 100 contributors. This paper reviews data on sightings and strandings for small cetaceans in Kenya collated by the KMMN. From 2011 to 2019, 792 records of 11 species of small cetaceans were documented. The most frequently reported inshore species were the Indo-Pacific bottlenose dolphin and Indian Ocean humpback dolphin. Offshore species, included killer whales, short-finned pilot whale and long-snouted spinner dolphin. Indo-Pacific bottlenose dolphins, long-snouted spinner dolphins, striped dolphins and Risso’s dolphins were recorded through stranding reports. The efforts of the KMMN were disseminated through international meetings (International Whaling Commission, World Marine Mammal Conference), national status reports, outreach and social media. Data has also supported the identification of three IUCN Important Marine Mammal Areas and one Area of Interest in Kenya. Further research is needed to improve estimates of cetacean abundance and distribution, particularly in unstudied coastal areas, and to assess the extent of anthropogenic threats associated with fisheries, coastal and port development, seismic exercises and unregulated tourism. The expansion of the network should benefit from the participation of remote coastal fishing communities, government research agencies, tourism and seismic operations, among others. The KMMN demonstrated the value of dedicated and citizen science data to enhance marine mammal conservation strategies to boost awareness and eco-tourism and to bring the public and science closer together, promoting research and effective conservation efforts.

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Spatial and temporal variation in the occurrence of bottlenose dolphins in the Chesapeake Bay, USA, using citizen science sighting data

PLoS ONE ◽

10.1371/journal.pone.0251637 ◽

2021 ◽

Vol 16 (5) ◽

pp. e0251637

Author(s):

Lauren Kelly Rodriguez ◽

Amber D. Fandel ◽

Benjamin R. Colbert ◽

Jamie C. Testa ◽

Helen Bailey

Keyword(s):

Chesapeake Bay ◽

Citizen Science ◽

Marine Mammals ◽

Generalized Additive Models ◽

Bottlenose Dolphins ◽

Temporal Distribution ◽

Additive Models ◽

Spatial And Temporal Variation ◽

Estuarine System ◽

Predictive Tool

Bottlenose dolphins (Tursiops truncatus) are migratory marine mammals that live in both open-ocean and coastal habitats. Although widely studied, little is known about their occurrence patterns in the highly urbanized estuary of the Chesapeake Bay, USA. The goal of this study was to establish the spatial and temporal distribution of bottlenose dolphins throughout this large estuarine system and use statistical modeling techniques to determine how their distribution relates to environmental factors. Three years (April-October 2017–2019) of dolphin sighting reports from a citizen-science database, Chesapeake DolphinWatch, were analyzed. The dolphins had a distinct temporal pattern, most commonly sighted during summer months, peaking in July. This pattern of observed occurrence was confirmed with systematic, passive acoustic detections of dolphin echolocation clicks from local hydrophones. Using spatially-exclusive Generalized Additive Models (GAM), dolphin presence was found to be significantly correlated to spring tidal phase, warm water temperature (24–30°C), and salinities ranging from 6–22 PPT. We were also able to use these GAMs to predict dolphin occurrence in the Bay. These predictions were statistically correlated to the actual number of dolphin sighting reported to Chesapeake DolphinWatch during that time. These models for dolphin presence can be implemented as a predictive tool for species occurrence and inform management of this protected species within the Chesapeake Bay.

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Age determination of common bottlenose dolphins (Tursiops truncatus) using dental radiography pulp:tooth area ratio measurements

PLoS ONE ◽

10.1371/journal.pone.0242273 ◽

2020 ◽

Vol 15 (11) ◽

pp. e0242273

Author(s):

Jean M. Herrman ◽

Jeanine S. Morey ◽

Ryan Takeshita ◽

Sylvain De Guise ◽

Randall S. Wells ◽

...

Keyword(s):

Life Histories ◽

Marine Mammals ◽

Bottlenose Dolphins ◽

Age Determination ◽

Area Ratio ◽

Dental Radiography ◽

Ratio Method ◽

Data Sets ◽

Photo Identification ◽

Development And Validation

Age is an important parameter to better understand wildlife populations, and is especially relevant for interpreting data for fecundity, health, and survival assessments. Estimating ages for marine mammals presents a particular challenge due to the environment they inhabit: accessibility is limited and, when temporarily restrained for assessment, the window of opportunity for data collection is relatively short. For wild dolphins, researchers have described a variety of age-determination techniques, but the gold-standard relies upon photo-identification to establish individual observational life histories from birth. However, there are few populations with such long-term data sets, therefore alternative techniques for age estimation are required for individual animals without a known birth period. While there are a variety of methods to estimate ages, each involves some combination of drawbacks, including a lack of precision across all ages, weeks-to-months of analysis time, logistical concerns for field applications, and/or novel techniques still in early development and validation. Here, we describe a non-invasive field technique to determine the age of small cetaceans using periapical dental radiography and subsequent measurement of pulp:tooth area ratios. The technique has been successfully applied for bottlenose dolphins briefly restrained during capture-release heath assessments in various locations in the Gulf of Mexico. Based on our comparisons of dental radiography data to life history ages, the pulp:tooth area ratio method can reliably provide same-day estimates for ages of dolphins up to about 10 years old.

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Crebl2 regulates cell metabolism in muscle and liver cells

Scientific Reports ◽

10.1038/s41598-019-56407-w ◽

2019 ◽

Vol 9 (1) ◽

Author(s):

Marcel Tiebe ◽

Marilena Lutz ◽

Deniz Senyilmaz Tiebe ◽

Aurelio A. Teleman

Keyword(s):

Transcription Factors ◽

Glucose Uptake ◽

Metabolic Response ◽

Cell Metabolism ◽

Cellular Metabolism ◽

Nutrient Sensing ◽

C2c12 Myoblasts ◽

Elevated Glucose ◽

Triglyceride Biosynthesis ◽

Transcriptional Induction

AbstractWe previously identified Drosophila REPTOR and REPTOR-BP as transcription factors downstream of mTORC1 that play an important role in regulating organismal metabolism. We study here the mammalian ortholog of REPTOR-BP, Crebl2. We find that Crebl2 mediates part of the transcriptional induction caused by mTORC1 inhibition. In C2C12 myoblasts, Crebl2 knockdown leads to elevated glucose uptake, elevated glycolysis as observed by lactate secretion, and elevated triglyceride biosynthesis. In Hepa1-6 hepatoma cells, Crebl2 knockdown also leads to elevated triglyceride levels. In sum, this works identifies Crebl2 as a regulator of cellular metabolism that can link nutrient sensing via mTORC1 to the metabolic response of cells.

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On the electrodynamic self-energy of the electron

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1948.0110 ◽

1948 ◽

Vol 195 (1041) ◽

pp. 163-173

Keyword(s):

Perturbation Theory ◽

Wave Equation ◽

Quantum Electrodynamics ◽

Energy State ◽

Energy Eigenvalue ◽

Expansion Method ◽

Negative Energy ◽

The Self ◽

Variation Principle ◽

Self Energy

The stationary-state wave equation for an electron at rest in a negative-energy state in interaction with only its own electromagnetic field is considered. Quantum electrodynamics, single-electron theory and a ‘cut-off’ procedure in momentum-space are used. Expressions in the form of expansions in powers of e 2 /hc are derived for the wave function ψ and the energy-eigenvalue E by a method which (unlike perturbation theory) is not based on the assumption that the self-energy is small. The convergence of the expansion for E is not proved rigorously but the first few terms are shown to decrease rapidly. For low cut-off frequencies K 0 the expression for E behaves as the equivalent perturbation expression but for large K 0 it behaves as — J(e 2 /hc) hK0. The variation principle is applied to an approximation (obtained from the expansion method) for r/r, and it is proved rigorously that for large K 0 the self-energy is algebraically less than or equal to —J(e 2 /hc) hK 0 . Hence, if the electron wave-equation is considered as the limiting case of the ‘cut-off’ equation as K 0 ->ao, it is established that the divergences obtained are not merely due to improper use of perturbation theory and that the self-energy is indeed infinite.

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Biochemical and physiological function of stearoyl-CoA desaturase

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.90897.2008 ◽

2009 ◽

Vol 297 (1) ◽

pp. E28-E37 ◽

Cited By ~ 335

Author(s):

Chad M. Paton ◽

James M. Ntambi

Keyword(s):

Metabolic Diseases ◽

De Novo ◽

Metabolic Response ◽

Control Point ◽

Lipid Synthesis ◽

Monounsaturated Fatty Acids ◽

Fatty Acyl ◽

Physiological Importance ◽

Stearoyl Coa Desaturase

A key and highly regulated enzyme that is required for the biosynthesis of monounsaturated fatty acids is stearoyl-CoA desaturase (SCD), which catalyzes the D9- cis desaturation of a range of fatty acyl-CoA substrates. The preferred substrates are palmitoyl- and stearoyl-CoA, which are converted into palmitoleoyl- and oleoyl-CoA respectively. Oleate is the most abundant monounsaturated fatty acid in dietary fat and is therefore readily available. Studies of mice that have a naturally occurring mutation in the SCD-1 gene isoform as well as a mouse model with a targeted disruption of the SCD gene (SCD-1−/−) have revealed the role of de novo synthesized oleate and thus the physiological importance of SCD-1 expression. SCD-1 deficiency results in reduced body adiposity, increased insulin sensitivity, and resistance to diet-induced obesity. The expression of several genes of lipid oxidation are upregulated, whereas lipid synthesis genes are downregulated. SCD-1 was also found to be a component of the novel metabolic response to the hormone leptin. Therefore, SCD-1 appears to be an important metabolic control point, and inhibition of its expression could be of benefit for the treatment of obesity, diabetes, and other metabolic diseases. In this article, we summarize the recent and timely advances concerning the important role of SCD in the biochemistry and physiology of lipid metabolism.

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The diving physiology of bottlenose dolphins (Tursiops truncatus). II. Biomechanics and changes in buoyancy at depth

Journal of Experimental Biology ◽

10.1242/jeb.202.20.2749 ◽

1999 ◽

Vol 202 (20) ◽

pp. 2749-2761 ◽

Cited By ~ 16

Author(s):

R.C. Skrovan ◽

T.M. Williams ◽

P.S. Berry ◽

P.W. Moore ◽

R.W. Davis

Keyword(s):

Tursiops Truncatus ◽

Marine Mammals ◽

Bottlenose Dolphins ◽

Neutral Buoyancy ◽

Swimming Mode ◽

Locomotor Patterns ◽

The Cost ◽

Physical Changes ◽

And Behavior ◽

Limited Oxygen

During diving, marine mammals must balance the conservation of limited oxygen reserves with the metabolic costs of swimming exercise. As a result, energetically efficient modes of locomotion provide an advantage during periods of submergence and will presumably increase in importance as the animals perform progressively longer dives. To determine the effect of a limited oxygen supply on locomotor performance, we compared the kinematics and behavior of swimming and diving bottlenose dolphins. Adult bottlenose dolphins (Tursiops truncatus) were trained to swim horizontally near the water surface or submerged at 5 m and to dive to depths ranging from 12 to 112 m. Swimming kinematics (preferred swimming mode, stroke frequency and duration of glides) were monitored using submersible video cameras (Sony Hi-8) held by SCUBA divers or attached to a pack on the dorsal fin of the animal. Drag and buoyant forces were calculated from patterns of deceleration for horizontally swimming and vertically diving animals. The results showed that dolphins used a variety of swimming gaits that correlated with acceleration. The percentage of time spent gliding during the descent phase of dives increased with depth. Glide distances ranged from 7.1+/−1.9 m for 16 m dives to 43.6+/−7.0 m (means +/− s.e.m.) for 100 m dives. These gliding patterns were attributed to changes in buoyancy associated with lung compression at depth. By incorporating prolonged glide periods, the bottlenose dolphin realized a theoretical 10–21 % energetic savings in the cost of a 100 m dive in comparison with dives based on neutral buoyancy models. Thus, modifying locomotor patterns to account for physical changes with depth appears to be one mechanism that enables diving mammals with limited oxygen stores to extend the duration of a dive.

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Occurrence of Brucella ceti in stranded bottlenose dolphins Tursiops truncatus coincides with calving season

Diseases of Aquatic Organisms ◽

10.3354/dao03526 ◽

2020 ◽

Vol 141 ◽

pp. 185-193

Author(s):

WE McFee ◽

D Wu ◽

K Colegrove ◽

K Terio ◽

L Balthis ◽

...

Keyword(s):

South Carolina ◽

Tursiops Truncatus ◽

Marine Mammals ◽

Marine Bacterium ◽

Bottlenose Dolphins ◽

Global Public Health ◽

Terrestrial Species ◽

Long Term Study ◽

Calving Season

Brucellosis is a disease caused by the Gram-negative facultative intracellular bacterium Brucella spp. In terrestrial species, this zoonotic bacterium is a global public health risk, but there is also concern over the zoonotic potential of marine forms, such as B. ceti, which affects cetaceans. Due to the detection of B. ceti in samples from bottlenose dolphins Tursiops truncatus during the 2010-2014 Gulf of Mexico Unusual Mortality Event, a long-term study of the prevalence of Brucella in stranded bottlenose dolphins from South Carolina, USA, was conducted. From 2012 through 2017, 282 stranded bottlenose dolphins were tested for B. ceti via real-time PCR. Nearly 32% of the dolphins tested positive in at least one sample (brain, lung, blowhole swab). Very little information exists in the literature on the occurrence of Brucella spp. in marine mammals, though in terrestrial species, such as cattle and elk, higher prevalence is often reported in spring. Similar results were found in this study with the peak occurrence being between March and June, a known period of calving in South Carolina. Results from this study provide important insights into the occurrence of the marine bacterium B. ceti.

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Short Communication: Erythrocytes and leukocytes profiles of bottlenose dolphins (Tursiops aduncus) at conservation site

Biodiversitas Journal of Biological Diversity ◽

10.13057/biodiv/d210760 ◽

2020 ◽

Vol 21 (7) ◽

Author(s):

Aryani Sismin Satyaningtijas ◽

AGUSTIN INDRAWATI ◽

RIZKA F. SYARAFINA ◽

TALITA F. MILANI ◽

M. SURYAPUTRA ◽

...

Keyword(s):

Health Monitoring ◽

Marine Mammals ◽

Short Communication ◽

Bottlenose Dolphins ◽

Physiological Status ◽

Tursiops Aduncus ◽

Lymphocyte Ratio ◽

Blood Smears ◽

Human Care ◽

Thin Blood Smears

Abstract. Satyaningtijas AS, Indrawati A, Syarafina RF, Milani TF, Saleema AK. 2020. Short Communication: Erythrocytes and leukocytes profiles of bottlenose dolphins (Tursiops aduncus) at conservation site. Biodiversitas 21: 3359-3363. Health monitoring of dolphins to ensure optimal welfare in human care is important. This study measured erythrocytes and leukocytes in seven bottlenose dolphins (Tursiops aduncus) as a parameter to assess physiological status in PT. Wersut Seguni Indonesia (WSI) Marine Mammals Conservation. Blood was sampled through the superficial veins of each tail fin for examination of erythrocytes and leukocytes using hemocytometer method. Differential leukocytes were observed using thin blood smears stained by Giemza. The purpose of this study to collect hematological value of captive bottlenose dolphins. The results showed values of erythrocytes was (5.14±0.56) x 106/mm3, (13.86±1.68) gr/dl for hemoglobin, and (44.29±2.69)% for hematocrit. The value for leukocytes were (4.2 ± 0,82) x 103/mm3 , 63.14 ± 9.77% for lymphocytes, 3.57 ± 1.72% for monocytes, 31.57 ± 8.43% for neutrophils, 1.29 ± 1.60% for eosinophils and 0.14 ± 0.38% for basophils. The average of the seven bottlenose dolphins Neutrophil to Lymphocyte ratio (N/L) was 0.53.

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