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High genetic diversity and distinct ancient lineage of Asiatic black bears revealed by non-invasive surveys in the Annapurna Conservation Area, Nepal.

ABSTRACT: Asiatic black bears (Ursus thibetanus) have a widespread distribution in mountain landscapes, and are considered vulnerable globally, but are low-priority species for conservation in Nepal. Habitat fragmentation, illegal hunting, and human-bear conflict are the major threats to Asiatic black bears across their global range. Having an adequate level of genetic variation in a population helps with adapting to rapidly changing environments, and thus is important for the long-term health of bear populations. Accordingly, we conducted non-invasive surveys of bear populations in the Annapurna Conservation Area (ACA) to elucidate genetic diversity, genetic structure, and the phylogenetic relationship of Asiatic black bears from this region of Nepal to other subspecies. To assess levels of genetic diversity and population genetic structure, we genotyped eight microsatellite loci using 147 samples, identifying 60 individuals in an area of approximately 525 km2. We found that the Asiatic black bear population in the ACA has maintained high levels of genetic diversity (HE = 0.76) as compared to other bear populations from range countries. We did not detect a signature of population substructure among sampling localities and this suggests that animals are moving freely across the landscape within the ACA. We also detected a moderate population size that may increase with the availability of suitable habitat in the ACA, so bear-related conflict should be addressed to ensure the long-term viability of this expanding bear populations. Primers specific to bears were designed to amplify a 675 bp fragment of the mitochondrial control region from the collected samples. Three haplotypes were observed from the entire conservation area. The complete mitochondrial genome (16,771 bp), the first obtained from wild populations of the Himalayan black bear (U. t. laniger), was also sequenced to resolve the phylogenetic relationships of closely related subspecies of Asiatic black bears. The resulting phylogeny indicated that Himalayan black bear populations in Nepal are evolutionary distinct from other known subspecies of Asiatic black bears.

SUBMITTER: Kadariya R

PROVIDER: S-EPMC6281213 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundAcross China and Southeast Asia, an estimated 17,000 bears are currently farmed for bile, primarily for traditional medicines. Depending on country, bile is extracted daily via transabdominal gallbladder fistulas, indwelling catheters, or needle aspiration. Despite claims that bears do not develop adverse effects from bile extraction, health issues identified in bears removed from bile farms include bile-extraction site infections, abdominal hernias, peritonitis, cholecystitis, hepatic neoplasia, cardiac disease, skeletal abnormalities, and abnormal behaviors. We present a comprehensive assessment of the effects of bile farming by comparing serum biochemical and hematological values of bears from farms that were bile-extracted (BE) and bears from farms not bile-extracted (FNE) with bears from non-farm captive (ZOO) and free-range (FR) environments. We hypothesized BE bears would have significant laboratory abnormalities compared to all non-extracted bear groups. We also hypothesized BE bears would have reduced long-term survival compared to FNE bears despite removal from farms.ResultsBE bears exhibited the highest values and greatest variation (on a population level) in laboratory parameters compared to all non-extracted bear groups particularly for alanine transaminase, gamma glutamyltransferase (GGT), total bilirubin (TBIL), alkaline phosphatase (ALKP), blood urea nitrogen, creatinine (CREA), and total white blood cell count. Significant differences were detected between bear groups when accounting for season, sex, and/or age. BE bears exhibited greater mean serum GGT compared to all non-extracted bear groups, and the odds of having elevated TBIL were 7.3 times greater for BE bears, consistent with hepatobiliary disease. Biochemical parameter elevations in BE bears persisted up to 14 years post-rescue, consistent with long-term effects of bile-extraction. BE bears that arrived with elevated CREA and ALKP had median survival times of 1 and 4 years respectively, and regardless of laboratory abnormalities, BE bears had significantly shorter survival times compared to FNE bears.ConclusionsOur results provide strong evidence that bile extraction practices not only represent a temporary constraint for bears' welfare, but confer distinct long-term adverse health consequences. Routine laboratory panels may be insensitive to detect the extent of underlying illness in BE bears as these bears have significantly reduced survival regardless of biochemical assessment compared to FNE bears.

Project description:Across Southeast Asia and China, more than 17000 Asian bears are kept under suboptimal conditions and farmed for their bile to meet the consumer demand for traditional medicine products. Years of unsterile and repetitive bile extraction contribute to the development of chronic sterile or bacterial cholecystitis, a pathology commonly diagnosed in formerly bile-farmed bears. In both human and veterinary medicine, the diagnostic value of the macroscopic bile examination for assessing gallbladder disease is unclear. The objective of this study is to identify the role of gallbladder bile color, viscosity, and turbidity, while comparing them with established markers of cholecystitis. Moreover, it aims to define the optimal duration of oral antibiotic treatment for chronic bacterial cholecystitis in bears associated with bile farming. Thirty-nine adult, formerly bile-farmed Asiatic black bears (Ursus thibetanus) were examined under anesthesia and underwent percutaneous ultrasound guided cholecystocentesis. A total of 59 bile samples were collected with 20 animals sampled twice to evaluate the therapeutic success. All bile aspirates were assessed macroscopically and microscopically followed by submission for bacterial culture and antimicrobial sensitivity. In the majority of bears, samples with cytological evidence of bactibilia lacked inflammatory cells and did not always correlate with positive bacterial cultures. The most common bacterial isolates were Enterococcus spp, Streptococcus spp and Escherichia coli. Based on our findings, the optimal duration of antibiotic treatment for chronic bacterial cholecystitis is 30 days. Moreover, unlike Gamma-glutamyl Transferase (GGT) and gallbladder wall thickness, the organoleptic properties of bile were found to be reliable markers of chronic gallbladder inflammation with color and turbidity indicating cholestasis. The current study highlights the importance of cholecystocentesis for the management of gallbladder disease and provides initial results on the possible diagnostic value of macroscopic bile examination.

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High genetic diversity and distinct ancient lineage of Asiatic black bears revealed by non-invasive surveys in the Annapurna Conservation Area, Nepal.

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