Subclinical thiamine deficiency results in failed reproduction in Arctic foxes
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ABSTRACT:
SUBMITTER: Jackson C
PROVIDER: S-EPMC10867461 | biostudies-literature | 2024 Feb
REPOSITORIES: biostudies-literature
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Project description:The Baltic Sea population of the common eider (Somateria mollissima) has declined dramatically during the last two decades. Recently, widespread episodic thiamine (vitamin B1) deficiency has been demonstrated in feral birds and suggested to contribute significantly to declining populations. Here we show that the decline of the common eider population in the Baltic Sea is paralleled by high mortality of the pulli a few days after hatch, owing to thiamine deficiency and probably also thereby associated abnormal behaviour resulting in high gull predation. An experiment with artificially incubated common eider eggs collected in the field revealed that thiamine treatment of pulli had a therapeutic effect on the thiamine status of the brain and prevented death. The mortality was 53% in untreated specimens, whereas it was only 7% in thiamine treated specimens. Inability to dive was also linked to brain damage typical for thiamine deficiency. Our results demonstrate how thiamine deficiency causes a range of symptoms in the common eider pulli, as well as massive die-offs a few days after hatch, which probably are the major explanation of the recent dramatic population declines.
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Project description:A new amdoparvovirus, named raccoon dog and fox amdoparvovirus (RFAV), was identified in farmed sick raccoon dogs and arctic foxes. Phylogenetic analyses showed that RFAV belongs to a new species within the genus Amdoparvovirus of the family Parvoviridae. An RFAV strain was isolated in Crandell feline kidney cell culture.
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Project description:ObjectiveThe arctic fox (Vulpes lagopus) is a circumpolar species inhabiting all accessible Arctic tundra habitats. The species forms a panmictic population over areas connected by sea ice, but recently, kin clustering and population differentiation were detected even in regions where sea ice was present. The purpose of this study was to examine the genetic structure of a population in the High Arctic using a robust panel of highly polymorphic microsatellites.ResultsWe analyzed the genotypes of 210 individuals from Bylot Island, Nunavut, Canada, using 15 microsatellite loci. No pattern of isolation-by-distance was detected, but a spatial principal component analysis (sPCA) revealed the presence of genetic subdivisions. Overall, the sPCA revealed two spatially distinct genetic clusters corresponding to the northern and southern parts of the study area, plus another subdivision within each of these two clusters. The north-south genetic differentiation partly matched the distribution of a snow goose colony, which could reflect a preference for settling into familiar ecological environments. Secondary clusters may result from higher-order social structures (neighbourhoods) that use landscape features to delimit their borders. The cryptic genetic subdivisions found in our population may highlight ecological processes deserving further investigations in arctic foxes at larger, regional spatial scales.
| S-EPMC5710073 | biostudies-literature
Project description:Thiamine deficiency is a well-known risk factor for the development of severe encephalopathy, such as Wernicke encephalopathy and Korsakoff syndrome, but the underlying mechanism is still mysterious. This study aims to investigate the expression levels of thiamine metabolism genes in different tissues and their impact on brain susceptibility to thiamine deficiency. The mRNA and protein levels of four genes known to be associated with thiamine metabolism: thiamine pyrophosphokinase-1 ( Tpk ), Solute carrier family 19 member 2 ( Slc19a2 ), Slc19a3 , and Slc25a19 , in the brain, kidney, and liver of mice were examined. Thiamine diphosphate (TDP) levels were measured in these tissues. Mice were subjected to dietary thiamine deprivation plus pyrithiamine (PTD), a specific TPK inhibitor, or pyrithiamine alone to observe the reduction in TDP and associated pathological changes. TPK mRNA and protein expression levels were lowest in the brain compared to the kidney and liver. Correspondingly, TDP levels were also lowest in the brain. Mice treated with PTD or pyrithiamine alone showed an initial reduction in brain TDP levels, followed by reductions in the liver and kidney. PTD treatment caused significant neuron loss, neuroinflammation, and blood-brain barrier disruption, whereas dietary thiamine deprivation alone did not. TPK expression level is the best indicator of thiamine metabolism status. Low TPK expression in the brain appears likely to contribute to brain susceptibility to thiamine deficiency, underscoring a critical role of TPK in maintaining cerebral thiamine metabolism and preventing thiamine deficiency-related brain lesions.
| S-EPMC11389888 | biostudies-literature
Project description:BackgroundTissue-specific stable isotope signatures can provide insights into the trophic ecology of consumers and their roles in food webs. Two parameters are central for making valid inferences based on stable isotopes, isotopic discrimination (difference in isotopic ratio between consumer and its diet) and turnover time (renewal process of molecules in a given tissue usually measured when half of the tissue composition has changed). We investigated simultaneously the effects of age, sex, and diet types on the variation of discrimination and half-life in nitrogen and carbon stable isotopes (δ¹⁵N and δ¹³C, respectively) in five tissues (blood cells, plasma, muscle, liver, nail, and hair) of a top predator, the arctic fox Vulpes lagopus.Methodology/principal findingsWe fed 40 farmed foxes (equal numbers of adults and yearlings of both sexes) with diet capturing the range of resources used by their wild counterparts. We found that, for a single species, six tissues, and three diet types, the range of discrimination values can be almost as large as what is known at the scale of the whole mammalian or avian class. Discrimination varied depending on sex, age, tissue, and diet types, ranging from 0.3‰ to 5.3‰ (mean = 2.6‰) for δ¹⁵N and from 0.2‰ to 2.9‰ (mean = 0.9‰) for δ¹³C. We also found an impact of population structure on δ¹⁵N half-life in blood cells. Varying across individuals, δ¹⁵N half-life in plasma (6 to 10 days) was also shorter than for δ¹³C (14 to 22 days), though δ¹⁵N and δ¹³C half-lives are usually considered as equal.Conclusion/significanceOverall, our multi-factorial experiment revealed that at least six levels of isotopic variations could co-occur in the same population. Our experimental analysis provides a framework for quantifying multiple sources of variation in isotopic discrimination and half-life that needs to be taken into account when designing and analysing ecological field studies.
| S-EPMC3121787 | biostudies-literature
Project description:Species that seasonally moult from brown to white to match snowy backgrounds become conspicuous and experience increased predation risk as snow cover duration declines. Long-term adaptation to camouflage mismatch in a changing climate might occur through phenotypic plasticity in colour moult phenology and or evolutionary shifts in moult rate or timing. Also, adaptation may include evolutionary shifts towards winter brown phenotypes that forgo the winter white moult. Most studies of these processes have occurred in winter white populations, with little attention to polymorphic populations with sympatric winter brown and winter white morphs. Here, we used remote camera traps to record moult phenology and mismatch in two polymorphic populations of Arctic foxes in Sweden over 2 years. We found that the colder, more northern population moulted earlier in the autumn and later in the spring. Next, foxes moulted earlier in the autumn and later in the spring during colder and snowier years. Finally, white foxes experienced relatively low camouflage mismatch while blue foxes were mismatched against snowy backgrounds most of the autumn through the spring. Because the brown-on-white mismatch imposes no evident costs, we predict that as snow duration decreases, increasing blue morph frequencies might help facilitate species persistence.
| S-EPMC9667137 | biostudies-literature
Project description:To quantify the ecological effects of predator populations, it is important to evaluate how population-level specializations are dictated by intra- versus inter-individual dietary variation. Coastal habitats contain prey from the terrestrial biome, the marine biome and prey confined to the coastal region. Such habitats have therefore been suggested to better support predator populations compared to habitats without coastal access. We used stable isotope data on a small generalist predator, the arctic fox, to infer dietary strategies between adult and juvenile individuals with and without coastal access on Iceland. Our results suggest that foxes in coastal habitats exhibited a broader isotope niche breadth compared to foxes in inland habitats. This broader niche was related to a greater diversity of individual strategies rather than to a uniform increase in individual niche breadth or by individuals retaining their specialization but increasing their niche differentiation. Juveniles in coastal habitats exhibited a narrower isotope niche breadth compared to both adults and juveniles in inland habitats, and juveniles in inland habitats inhabited a lower proportion of their total isotope niche compared to adults and juveniles from coastal habitats. Juveniles in both habitats exhibited lower intra-individual variation compared to adults. Based on these results, we suggest that foxes in both habitats were highly selective with respect to the resources they used to feed offspring, but that foxes in coastal habitats preferentially utilized marine resources for this purpose. We stress that coastal habitats should be regarded as high priority areas for conservation of generalist predators as they appear to offer a wide variety of dietary options that allow for greater flexibility in dietary strategies.
| S-EPMC3291546 | biostudies-literature
Project description:BackgroundThe genus Vulpes (true foxes) comprises numerous species that inhabit a wide range of habitats and climatic conditions, including one species, the Arctic fox (Vulpes lagopus) which is adapted to the arctic region. A close relative to the Arctic fox, the red fox (Vulpes vulpes), occurs in subarctic to subtropical habitats. To study the genetic basis of their adaptations to different environments, transcriptome sequences from two Arctic foxes and one red fox individual were generated and analyzed for signatures of positive selection. In addition, the data allowed for a phylogenetic analysis and divergence time estimate between the two fox species.ResultsThe de novo assembly of reads resulted in more than 160,000 contigs/transcripts per individual. Approximately 17,000 homologous genes were identified using human and the non-redundant databases. Positive selection analyses revealed several genes involved in various metabolic and molecular processes such as energy metabolism, cardiac gene regulation, apoptosis and blood coagulation to be under positive selection in foxes. Branch site tests identified four genes to be under positive selection in the Arctic fox transcriptome, two of which are fat metabolism genes. In the red fox transcriptome eight genes are under positive selection, including molecular process genes, notably genes involved in ATP metabolism. Analysis of the three transcriptomes and five Sanger re-sequenced genes in additional individuals identified a lower genetic variability within Arctic foxes compared to red foxes, which is consistent with distribution range differences and demographic responses to past climatic fluctuations. A phylogenomic analysis estimated that the Arctic and red fox lineages diverged about three million years ago.ConclusionsTranscriptome data are an economic way to generate genomic resources for evolutionary studies. Despite not representing an entire genome, this transcriptome analysis identified numerous genes that are relevant to arctic adaptation in foxes. Similar to polar bears, fat metabolism seems to play a central role in adaptation of Arctic foxes to the cold climate, as has been identified in the polar bear, another arctic specialist.
| S-EPMC4528681 | biostudies-literature
Project description:The parasites of arctic foxes in the central Canadian Arctic have not been well described. Canada's central Arctic is undergoing dramatic environmental change, which is predicted to cause shifts in parasite and wildlife species distributions, and trophic interactions, requiring that baselines be established to monitor future alterations. This study used conventional, immunological, and molecular fecal analysis techniques to survey the current gastrointestinal endoparasite fauna currently present in arctic foxes in central Nunavut, Canada. Ninety-five arctic fox fecal samples were collected from the terrestrial Karrak Lake ecosystem within the Queen Maud Gulf Migratory Bird Sanctuary. Samples were examined by fecal flotation to detect helminths and protozoa, immunofluorescent assay (IFA) to detect Cryptosporidium and Giardia, and quantitative PCR with melt-curve analysis (qPCR-MCA) to detect coccidia. Positive qPCR-MCA products were sequenced and analyzed phylogenetically. Arctic foxes from Karrak Lake were routinely shedding eggs from Toxascaris leonina (63%). Taeniid (15%), Capillarid (1%), and hookworm eggs (2%), Sarcocystis sp. sporocysts 3%), and Eimeria sp. (6%), and Cystoisospora sp. (5%) oocysts were present at a lower prevalence on fecal flotation. Cryptosporidium sp. (9%) and Giardia sp. (16%) were detected by IFA. PCR analysis detected Sarcocystis (15%), Cystoisospora (5%), Eimeria sp., and either Neospora sp. or Hammondia sp. (1%). Through molecular techniques and phylogenetic analysis, we identified two distinct lineages of Sarcocystis sp. present in arctic foxes, which probably derived from cervid and avian intermediate hosts. Additionally, we detected previously undescribed genotypes of Cystoisospora. Our survey of gastrointestinal endoparasites in arctic foxes from the central Canadian Arctic provides a unique record against which future comparisons can be made.
| S-EPMC3862500 | biostudies-literature
Project description:BackgroundCryptosporidium is an important genus of enteric zoonotic parasites, which can infect a wide range of animals including foxes. Little information is available concerning the prevalence and molecular characterisation of Cryptosporidium spp. in farmed Arctic foxes (Vulpes lagopus) in China. Thus, the objective of the present study was to investigate the prevalence of Cryptosporidium spp. in Arctic foxes in China using nested PCR amplification of the small subunit ribosomal RNA (SSU rRNA) gene.FindingsThe overall prevalence of Cryptosporidium spp. in Arctic foxes was 15.9 % (48/302), with 12.9 % in male (18/139) and 18.4 % in female (30/163) foxes, respectively. The prevalence in different farms varied from 0 to 31.43 %. The prevalence of infection in different age groups varied from 14.1 % to 19.0 %. Foxes from Hebei Province (7.8 %, 11/141) had a significantly lower Cryptosporidium spp. prevalence than those from Heilongjiang Province (22.9 %, 16/70) and Jilin Province (23.1 %, 21/91) (P= 0.0015). Sequence analysis of the SSU rRNA gene indicated that all the 48 isolates represented C. canis.ConclusionsThis is the first report of C. canis infection in farmed Arctic foxes in China, which also provides foundation data for preventing and controlling Cryptosporidium infection in foxes, other animals and humans.
| S-EPMC4776383 | biostudies-literature