Hematological and plasma profiles and ticks and tick-borne pathogens in wild Formosan black bears (Ursus thibetanus formosanus).

BACKGROUND: The endangered Formosan black bear (Ursus thibetanus formosanus) is the largest native carnivorous mammal in Taiwan. Diseases, poor management, illegal hunting, and habitat destruction are serious threats to the survival of bear populations. However, studies on the impact of diseases on bear populations are limited. Therefore, this study aimed to establish a database of the hematological and plasma profiles of free-ranging Formosan black bears and investigate the occurrence of ectoparasites, blood parasites, and vector-borne pathogens. METHODS: Formosan black bears were captured in Yushan National Park (YNP) and Daxueshan Forest Recreation Area (DSY) in Taiwan. Blood samples were collected from each bear for hematological analysis and plasma biochemistry using a hematology analyzer. Parasites and pathogens were detected using a thin blood smear with Wright-Giemsa staining and polymerase chain reaction (PCR) assay. Additionally, macroscopic ectoparasites were collected from bears to detect blood parasites and other pathogens. Moreover, the relationships between the bear variables (sex, age, and occurrence of parasites or pathogens), ectoparasites, and infectious agents were also analyzed. RESULTS: In all, 21 wild bears (14 in YNP and 7 in DSY) were captured and released during the satellite tracking studies. Hematological analysis and plasma biochemistry indicated significant differences in white blood cells (WBC), segments, creatine kinase (CK), and lactate dehydrogenase (LDH) levels between foot snare and culvert-captured bears. Additionally, there were significant differences in total plasma protein (TPP), creatinine, Ca2+, Mg2+, and K+ levels between male and female bears. Moreover, pathogen-infected bears had significantly higher erythrocyte sedimentation rate (ESR; 30 min and 1 h) and globulin levels than uninfected bears. In total, 240 ticks were collected from 13 bears, among which eight adult tick species were identified, including Haemaphysalis flava, Haemaphysalis hystricis, Amblyomma testudinarium, Ixodes ovatus, Dermacentor taiwanensis, Haemaphysalis longicornis, Ixodes acutitarsus, Amblyomma javanense, and nymphs belonging to Haemaphysalis spp. PCR revealed that 13 (61.90%) and 8 (38.10%) bears harbored Hepatozoon ursi and Babesia DNA, respectively. Among the ticks examined, 157 (65.41%) and 128 (53.33%) samples were positive for H. ursi and Babesia, respectively. CONCLUSIONS: To the best of our knowledge, this is the first study to establish a database of the hematological and plasma profiles of wild Formosan black bears and investigate ectoparasite infestation and Hepatozoon and Babesia spp. INFECTION: In conclusion, these findings may serve as a reference for monitoring the health and population of locally endangered bears.

ANALYSIS OF SERUM PROTEINS IN HEALTHY GIANT PANDAS (AILUROPODA MELANOLEUCA) UNDER MANAGED CARE.

Electrophoresis is a practical diagnostic tool for the identification of changes in serum protein fractions, which can be associated with a variety of diseases. Protein electrophoresis studies in Ursidae are limited, and currently no published fraction values are available for the giant panda (Ailuropoda melanoleuca). The aim of this study was to describe the serum protein fractions in the giant panda using both capillary zone electrophoresis (CZE) and standard agarose gel electrophoresis (AGE) techniques. Serum samples from nine healthy giant pandas (n = 19) were used for this study. Samples were evaluated using CZE and standard AGE. The CZE procedure successfully resolved serum proteins into seven fractions: prealbumin; albumin; and α1-, α2-, ß1-, ß2-, and γ-globulin; while AGE separated serum into only six protein fractions: prealbumin; albumin; α1-, α2-, and ß-globulins; and γ-globulin. These data will serve as a preliminary baseline for further studies and provide insight for the medical management of giant pandas.

Blood transcriptome analysis revealed the immune changes and immunological adaptation of wildness training giant pandas.

The giant panda (Ailuropoda melanoleuca) is a global flagship species for biodiversity conservation. As the time for captive giant pandas to be released into the wild matures, wildness training is provided to allow adaptation to their natural environment. It is assumed that changes in the immune system would be integral in this adaptation from captive to wild, where many more pathogens would be encountered in their natural habitats. Therefore, this study aims to determine the expression changes of immune-related genes and their potential as immunoassay markers for adaptation monitoring in wildness training giant pandas, and then to understand the adaptation strategy of wildness training giant pandas to the wild environment, thereby improving the success rate of panda reintroduction. We obtained 300 differentially expressed genes (DEGs) by RNA-seq, with 239 up-regulated and 61 down-regulated DEGs in wildness training giant pandas compared to captive pandas. Functional enrichment analysis indicated that up-regulated DEGs were enriched in several immune-related terms and pathways. There were 21 immune-related DEGs, in which most of them were up-regulated in wildness training giant pandas, including several critical innate and cellular immune genes. IL1R2 was the most significantly up-regulated gene and is a signature of homeostasis within the immune system. In the protein-protein interaction (PPI) analysis, CXCL8, CXCL10, and CCL5 were identified as the hub immune genes. Our results suggested that wildness training giant pandas have stronger innate and cellular immunity than captive giant pandas, and we proposed that a gene set of CXCL8, CXCL10, CCL5, CD3D, NFKBIA, TBX21, IL12RB2, and IL1R2 may serve as potential immunoassay markers to monitor and assess the immune status of wildness training giant pandas. Our study offers the first insight into immune alterations of wildness training giant pandas, paving the way for monitoring and evaluating the immune status of giant pandas when reintroducing them into the wild.

Supplementing cultured human myotubes with hibernating bear serum results in increased protein content by modulating Akt/FOXO3a signaling.

Hibernating bears remain in their dens for 5-7 months during winter and survive without eating or drinking while staying inactive. However, they maintain their physical functions with minimal skeletal muscle atrophy and metabolic dysfunction. In bears, resistance to skeletal muscle atrophy during hibernation is likely mediated by seasonally altered systemic factors that are independent of neuromuscular activity. To determine whether there are components in bear serum that regulate protein and energy metabolism, differentiated human skeletal muscle cells were treated with bear serum (5% in DMEM/Ham's F-12, 24 h) collected during active summer (July) and hibernating winter (February) periods. The serum samples were collected from the same individual bears (Ursus thibetanus japonicus, n = 7 in each season). Total protein content in cultured skeletal muscle cells was significantly increased following a 24 h treatment with hibernating bear serum. Although the protein synthesis rate was not altered, the expression of MuRF1 protein, a muscle-specific E3 ubiquitin ligase was significantly decreased along with a concomitant activation of Akt/FOXO3a signaling. Increased levels of insulin-like growth factor-1 (IGF-1) were also observed in hibernating bear serum. These observations suggest that protein metabolism in cultured human myotubes may be altered when incubated with hibernating bear serum, with a significant increase in serum IGF-1 and diminished MuRF1 expression, a potential target of Akt/FOXO3a signaling. A protein sparing phenotype in cultured muscle cells by treatment with hibernating bear serum holds potential for the development of methods to prevent human muscle atrophy and related disorders.

The Fecal and Serum Metabolomics of Giant Pandas Based on Untargeted Metabolomics.

Little is comprehensively known or understood about giant panda fecal and serum metabolites, which could serve as important indicators of the physiological metabolism of giant pandas. Therefore, we determined the contents of fecal and serum metabolites of giant pandas based on an untargeted metabolome. Four hundred and 955 metabolites were detected in the feces and serum of giant panda, respectively. Glycerophospholipid and choline metabolism were the main metabolic pathways in feces and serum. A significant correlation between the gut microbiota and fecal metabolites was found (P < 0.01). Fecal metabolites were not greatly affected by the age or gender of giant pandas, but serum metabolites were significantly affected by age and gender. The majority of different metabolites caused by age were higher in serum of younger giant pandas, including fatty acids, lipids, metabolites of bile acids, and intermediate products of vitamin D3. The majority of different metabolites caused by gender included fatty acids, phosphatidylcholine (PC), phosphatidylserine (PS), and phosphatidylethanolamine (PE). A separate feeding diet should be considered according to different ages and genders of giant panda. Therefore, our results could provide helpful suggestions to further protect captive giant pandas.

Expression of Paracrine Effectors in Human Adipose-Derived Mesenchymal Stem Cells Treated With Plasma From Brown Bears (Ursus arctos).

Adipose-derived mesenchymal stem cells (ADSCs) are promising candidates for novel cell therapeutic applications. Hibernating brown bears sustain tissue integrity and function via unknown mechanisms, which might be plasma borne. We hypothesized that plasma from hibernating bears may increase the expression of favorable factors from human ADSCs. In an experimental study, ADSCs from patients with ischemic heart disease were treated with interventional media containing plasma from hibernating and active bears, respectively, and with control medium. Extracted RNA from the ADSCs was sequenced using next generation sequencing. Statistical analyses of differentially expressed genes were performed using fold change analysis, pathway analysis, and gene ontology. As a result, we found that genes associated with inflammation, such as IGF1, PGF, IL11, and TGFA, were downregulated by > 10-fold in ADSCs treated with winter plasma compared with control. Genes important for cardiovascular development, ADM, ANGPTL4, and APOL3, were upregulated in ADSCs when treated with winter plasma compared with summer plasma. ADSCs treated with bear plasma, regardless if it was from hibernating or active bears, showed downregulation of IGF1, PGF, IL11, INHBA, IER3, and HMOX1 compared with control, suggesting reduced cell growth and differentiation. This can be summarized in the conclusion that plasma from hibernating bears suppresses inflammatory genes and activates genes associated with cardiovascular development in human ADSCs. Identifying the involved regulator(s) holds therapeutic potential.

A Translational Model for Venous Thromboembolism: MicroRNA Expression in Hibernating Black Bears.

BACKGROUND: Hibernating American black bears have significantly different clotting parameters than their summer active counterparts, affording them protection against venous thromboembolism during prolonged periods of immobility. We sought to evaluate if significant differences exist between the expression of microRNAs in the plasma of hibernating black bears compared with their summer active counterparts, potentially contributing to differences in hemostasis during hibernation. MATERIALS AND METHODS: MicroRNA sequencing was assessed in plasma from 21 American black bears in summer active (n = 11) and hibernating states (n = 10), and microRNA signatures during hibernating and active state were established using both bear and human genome. MicroRNA targets were predicted using messenger RNA (mRNA) transcripts from black bear kidney cells. In vitro studies were performed to confirm the relationship between identified microRNAs and mRNA expression, using artificial microRNA and human liver cells. RESULTS: Using the bear genome, we identified 15 microRNAs differentially expressed in the plasma of hibernating black bears. Of these microRNAs, three were significantly downregulated (miR-141-3p, miR-200a-3p, and miR-200c-3p), were predicted to target SERPINC1, the gene for antithrombin, and demonstrated regulatory control of the gene mRNA expression in cell studies. CONCLUSIONS: Our findings suggest that the hibernating black bears' ability to maintain hemostasis and achieve protection from venous thromboembolism during prolonged periods of immobility may be due to changes in microRNA signatures and possible upregulation of antithrombin expression.

Insights in the regulation of trimetylamine N-oxide production using a comparative biomimetic approach suggest a metabolic switch in hibernating bears.

Experimental studies suggest involvement of trimethylamine N-oxide (TMAO) in the aetiology of cardiometabolic diseases and chronic kidney disease (CKD), in part via metabolism of ingested food. Using a comparative biomimetic approach, we have investigated circulating levels of the gut metabolites betaine, choline, and TMAO in human CKD, across animal species as well as during hibernation in two animal species. Betaine, choline, and TMAO levels were associated with renal function in humans and differed significantly across animal species. Free-ranging brown bears showed a distinct regulation pattern with an increase in betaine (422%) and choline (18%) levels during hibernation, but exhibited undetectable levels of TMAO. Free-ranging brown bears had higher betaine, lower choline, and undetectable TMAO levels compared to captive brown bears. Endogenously produced betaine may protect bears and garden dormice during the vulnerable hibernating period. Carnivorous eating habits are linked to TMAO levels in the animal kingdom. Captivity may alter the microbiota and cause a subsequent increase of TMAO production. Since free-ranging bears seems to turn on a metabolic switch that shunts choline to generate betaine instead of TMAO, characterisation and understanding of such an adaptive switch could hold clues for novel treatment options in burden of lifestyle diseases, such as CKD.

PHARMACOKINETICS OF A SINGLE DOSE OF FLURALANER ADMINISTERED ORALLY TO AMERICAN BLACK BEARS (URSUS AMERICANUS).

Sarcoptic mange continues to impact free-ranging mammal populations, including the American black bear (Ursus americanus). Administration of a single oral dose of fluralaner may be a viable treatment option for captive and free-ranging black bears affected by mange. This novel ectoparasitic in the isoxazoline class acts as an inhibitor of γ-aminobutyric acid (GABA)-gated chloride channels and l-glutamate-gated chloride channels (GluCls) and is commercially available in the United States as a flea and tick preventative medication for domestic dogs and cats. Pharmacokinetic parameters of fluralaner were evaluated in clinically healthy American black bear cubs (n = 10) administered a single oral dose of fluralaner at a targeted minimum dose of 25 mg/kg. Blood was collected at 24 hr and 7, 14, 21, 28, 35, 42, 49, 56, 63, and 70 days, and harvested plasma was analyzed for drug concentration using high-performance liquid chromatography. The average half-life (Ke t1/2) was determined to be 4.9 days, which is shorter than that published in domestic dogs. It was estimated that the average drug withdrawal time is approximately 64-72 days in this species.

SEROLOGY AS A TOOL TO INVESTIGATE SARCOPTIC MANGE IN AMERICAN BLACK BEARS (URSUS AMERICANUS).

Black bears (Ursus americanus) have historically been considered an uncommon host for sarcoptic mange. However, over the last 25 yr, sarcoptic mange has been increasingly reported in black bears in the northeastern US. Syndromic monitoring is the most common surveillance approach for mange in bears, but tools to monitor exposure to Sarcoptes scabiei in bear populations have not been thoroughly evaluated under field conditions. In this study, we validated a commercially available enzyme-linked immunosorbent assay (ELISA), designed to detect antibodies against S. scabiei in dogs, for use in black bears with a sensitivity and specificity of 95.6% and 96.6%, respectively. To further examine the performance of this assay, serial serum samples from seven black bears with confirmed sarcoptic mange were collected posttreatment to determine the persistence of detectable antibody response with the ELISA. Antibodies in black bears waned to below the limit of detection between 4 and 14 wk, suggesting that serology studies might underestimate the number of exposed black bears after antibodies have waned. State-wide serosurveys in Pennsylvania from hunter-harvested black bears in 2017 and 2018 showed a significant difference in seroprevalence between regions with high occurrence of mange (mean seroprevalence 6.7%, range of 6.6-6.8%) and low occurrence of mange (no seropositive black bears were detected). Within Pennsylvania, these data indicate that the geographic distribution of exposure to S. scabiei, based on serologic testing, generally reflects the distribution of overt disease, as determined by syndromic surveillance. Collectively, these results indicate the evaluated ELISA is an effective tool for monitoring S. scabiei exposure in bear populations and provides the framework for additional studies regarding sarcoptic mange epidemiology in black bears.

SERUM TRACE NUTRIENT VALUES IN FOUR CAPTIVE GIANT PANDAS (AILUROPODA MELANOLEUCA).

Trace nutrients have been shown to play important health roles in both domestic and wild animals, but there has been little investigation into their values and effects in giant pandas (Ailuropoda melanoleuca). The goal of this study was to obtain serum vitamin and mineral values in a group of healthy, captive giant pandas (n = 4). Twenty-seven samples were obtained from the group from 2008 to 2012. Serum analytes measured included retinol, α-tocopherol, hydroxyvitamin D, cobalt (Co), copper (Cu), iron (Fe), manganese (Mn), molybdenum (Mo), selenium (Se), and zinc (Zn). The diet was evaluated for protein, fat, fiber, Ca, P, magnesium (Mg), potassium (K), sodium (Na), Fe, Zn, Cu, Mn, and Mo. Comparison with other giant panda nutrient values were made. Further research with increased sample sizes and different populations are warranted.

Heightened Immune System Function in Polar Bears Using Terrestrial Habitats.

Climate change is altering the distribution of some wildlife species while warming temperatures are facilitating the northward expansion of pathogens, potentially increasing disease risk. Melting of Arctic sea ice is increasingly causing polar bears (Ursus maritimus) of the southern Beaufort Sea (SBS) to spend summer on land, where they may encounter novel pathogens. Here, we tested whether SBS polar bears on shore during summer exhibited greater immune system activity than bears remaining on the sea ice. In addition, we tested whether the type of immune response correlated with body condition, because adaptive responses (slowly developing defenses against specific pathogens) often require less energy than innate responses (rapid defenses not based on pathogen identity). After accounting for body condition, we found that polar bears on shore exhibited higher total white blood cell counts, neutrophils, and monocytes than bears on the ice, suggesting more infections. Lymphocytes, eosinophils, basophils, and globulins did not differ. C-reactive protein, an indicator of inflammation, also did not differ between habitats. Body condition was associated with variables indicative of both innate and adaptive immunity, suggesting that neither response was uniquely limited by energy resources. Our data indicate that as more polar bears spend longer periods of time on shore, they may experience more infections. We encourage continued health monitoring of this species and studies of the long-term fitness consequences from disease.

Hundreds of Unrecognized Halogenated Contaminants Discovered in Polar Bear Serum.

Exposure of polar bears (Ursus maritimus) to persistent organic pollutants was discovered in the 1970s, but recent evidence suggests the presence of unknown toxic chemicals in their blood. Protein and phospholipid depleted serum was stirred with polyethersulfone capillaries to extract a broad range of analytes, and nontarget mass spectrometry with "fragmentation flagging" was used for detection. Hundreds of analytes were discovered belonging to 13 classes, including novel polychlorinated biphenyl (PCB) metabolites and many fluorinated or chlorinated substances not previously detected. All analytes were detected in the oldest (mid-1980s) archived polar bear serum from Hudson Bay and Beaufort Sea, and all fluorinated classes showed increasing trends. A mouse experiment confirmed the novel PCB metabolites, suggesting that these could be widespread in mammals. Historical exposure and toxic risk has been underestimated, and these halogenated contaminants pose uncertain risks to this threatened species.

SURVEY FOR EQUINE HERPESVIRUSES IN POLAR BEARS ( URSUS MARITIMUS) AND EXOTIC EQUIDS HOUSED IN US AZA INSTITUTIONS.

Infection by equine herpesvirus (EHV) strains (EHV-1, EHV-9) in ursid species, including polar bears ( Ursus maritimus), has been associated with neurological disease and death. A serosurvey of captive exotic equid and polar bear populations in US Association of Zoos and Aquaria institutions was performed to determine the prevalence of EHV strains using quantitative polymerase chain reaction (qPCR) and enzyme-linked immunosorbent assay (ELISA) tests. Equid species surveyed included zebra ( Equus spp.), Przewalski's wild horse ( Equus ferus przewalskii), Persian onager ( Equus hemionus), and Somali wild ass ( Equus africanus somaliensis). A questionnaire regarding husbandry and medical variables was distributed to institutions housing polar bears. No polar bears tested positive for EHVs on qPCR of blood or nasal swabs. No exotic equids tested positive for EHVs on qPCR of blood, but two exotic equids ( n = 2/22; 9%) tested positive for EHVs on qPCR of nasal swabs. On ELISA, polar bears infrequently were positive for EHV-1 ( n = 5/38; 13%). Exotic equids were positive for EHV-4 on ELISA more frequently ( n = 30/43; 70%) than for EHV-1 ( n = 8/43; 19%). Nine institutions submitted samples from both exotic equids and polar bears, two of which had both exotic equids and polar bears positive for EHVs by ELISA. Each of these institutions reported that the polar bear and exotic equid exhibits were within 80 m of each other and that risk factors for fomite transmission between exhibits based on husbandry practices were present. One institution that did not house exotic equids had a polar bear test positive for EHV-1 on ELISA, with no history of exposure to exotic equids. Further testing of captive polar bears and exotic equids is recommended, as is modification of husbandry practices to limit exposure of polar bears to exotic equids.

Isotopic Composition of Blood of Polar Bears (Ursus maritimus) of the Kara-Barents Sea Population.

The data on the content of carbon and nitrogen isotopes in the blood samples of polar bears obtained in the present study confirm that polar bears in the Taimyr region (and the Kara-Barents sea population in general) are partly dependent on the resources of terrestrial origin. However the "terrestrial carbon" evidently reaches bears' tissues indirectly, via marine food webs utilizing organic carbon brought into the polar basin by Siberian rivers.

Effects of biometrics, location and persistent organic pollutants on blood clinical-chemical parameters in polar bears (Ursus maritimus) from Svalbard, Norway.

In the present study, blood clinical-chemical parameters (BCCPs) were analysed in 20 female and 18 male Svalbard polar bears (Ursus maritimus) captured in spring 2007. The aim was to study how age, body condition (BC), biometrics, plasma lipid content and geographical location may confound the relationship between persistent organic pollutants (POPs) including PCBs, HCB, chlordanes, DDTs, HCHs, mirex and OH-PCBs and the concentrations of 12 specific BCCPs (hematocrit [HCT], hemoglobin [HB], aspartate aminotransferase [ASAT], alanine aminotransferase [ALAT], γ-glutamyltransferase [GGT], creatine kinase [CK], triglycerides [TG], cholesterol [CHOL], high-density lipoprotein [HDL], creatinine (CREA], urea, potassium (K]), and to investigate if any of these BCCPs may be applied as potential biomarkers for POP exposure in polar bears. Initial PCA and O-PLS modelling showed that age, lipids, BC and geographical location (longitude and latitude) were important parameters explaining BCCPs in females. Following subsequent partial correlation analyses correcting for age and lipids, multiple POPs in females were still significantly correlated with HCT and HDL (all p < 0.05). In males, age, BM, BC and longitude were important parameters explaining BCCPs. Following partial correlation analyses correcting for age, biometrics, lipids and longitude in males, multiple POPs were significantly correlated with HCT, ASAT, GGT and CHOL (all p < 0.05). In conclusion, several confounding parameters has to be taken into account when studying the relations between BCCPs and POPs in polar bears. When correcting for these, in particular HCT may be used as a simple cost-efficient biomarker of POP exposure in polar bears. Furthermore, decreasing HDL concentrations and increasing CHOL concentration with increasing POP concentrations may indicate responses related to increased risk of cardiovascular disease. We therefore suggest to further study POP exposure and lipidome response to increase knowledge of the risk of cardiometabolic syndrome in polar bears.

Blood Chemistry Reference Values for Free-Ranging Asiatic Black Bears ( Ursus thibetanus) by Season, Age, and Sex.

Physiological characteristics, such as blood chemistry values, are valuable for evaluating the health of the animals. To our knowledge, these values have never been reported for the free-ranging Asiatic black bear ( Ursus thibetanus; ABB). Thus, 28 blood chemistry values from 50 free-ranging ABBs captured in Jirisan National Park, Republic of Korea, from 2005 to 2016 were evaluated. The aim of this study was to establish blood chemistry reference values for the free-ranging ABBs during both the hibernating and nonhibernating seasons. During hibernation, mean values of creatinine (CRE), total cholesterol, total protein (TP), albumin (ALB), triglycerides, and magnesium were significantly higher than those during nonhibernation; however, mean values of blood urea nitrogen, urea nitrogen to creatinine (U/C) ratio, inorganic phosphorous (IP), aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase, lactate dehydrogenase (LDH), high-density lipoprotein cholesterol, and alkaline phosphatase (ALP) were significantly lower. Age differences (young vs. adult) were found in IP, LDH, TP, and ALB values during hibernation and in the U/C ratio, calcium, IP, ALP, creatine kinase myocardial band, CRE, total bilirubin, and uric acid values during nonhibernation. However, there were no sex differences (male vs. female).

Proteolysis inhibition by hibernating bear serum leads to increased protein content in human muscle cells.

Muscle atrophy is one of the main characteristics of human ageing and physical inactivity, with resulting adverse health outcomes. To date, there are still no efficient therapeutic strategies for its prevention and/or treatment. However, during hibernation, bears exhibit a unique ability for preserving muscle in conditions where muscle atrophy would be expected in humans. Therefore, our objective was to determine whether there are components of bear serum which can control protein balance in human muscles. In this study, we exposed cultured human differentiated muscle cells to bear serum collected during winter and summer periods, and measured the impact on cell protein content and turnover. In addition, we explored the signalling pathways that control rates of protein synthesis and degradation. We show that the protein turnover of human myotubes is reduced when incubated with winter bear serum, with a dramatic inhibition of proteolysis involving both proteasomal and lysosomal systems, and resulting in an increase in muscle cell protein content. By modulating intracellular signalling pathways and inducing a protein sparing phenotype in human muscle cells, winter bear serum therefore holds potential for developing new tools to fight human muscle atrophy and related metabolic disorders.

Blood Lead Levels in Captive Giant Pandas.

Fifteen giant pandas (Ailuropoda melanoleuca) from the Chinese Conservation and Research Center for the Giant Panda (CCRCGP) in Bifengxia, Sichuan, China were analyzed for blood lead concentrations (Pb-B) during the 2017 breeding season. Thirteen of the 15 bears showed Pb-B below the method detection limit (MDL) of 3.3 µg/dL. The two remaining bears, although above the MDL, contained very low concentrations of lead of 3.9 and 4.5 µg/dL. All 15 giant pandas in this analysis had Pb-B concentrations that were within normal background concentrations for mammals in uncontaminated environments. For a threatened species, whose native country is plagued by reports of extremely high air pollution, our findings suggest that giant pandas at the CCRCGP are not absorbing lead at concentrations that would adversely affect their health.

Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity.

The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.