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The red panda (Ailurus fulgens) is a distinctive mammal known for its reliance on a diet primarily consisting of bamboo. The gut microbiota and overall health of animals are strongly influenced by diets and environments. Therefore, conducting research to explore the taxonomical and functional variances within the gut microbiota of red pandas exposed to various dietary and environmental conditions could shed light on the dynamic complexities of their microbial communities. In this study, normal fecal samples were obtained from red pandas residing in captive and semi‐free environments under different dietary regimes and used for metabolomic, 16S rRNA, and metagenomic sequencing analysis, with the pandas classified into four distinct cohorts according to diet and environment. In addition, metagenomic sequencing was conducted on mucus fecal samples to elucidate potential etiological agents of disease. Results revealed an increased risk of gastrointestinal diseases in red pandas consuming bamboo shoots due to the heightened presence of pathogenic bacteria, although an increased presence of microbiota‐derived tryptophan metabolites appeared to facilitate intestinal balance. The red pandas fed bamboo leaves also exhibited a decrease in gut microbial diversity, which may be attributed to the antibacterial flavonoids and lower protein levels in leaves. Notably, red pandas residing in semi‐free environments demonstrated an enriched gut microbial diversity. Moreover, the occurrence of mucus secretion may be due to an increased presence of species associated with diarrhea and a reduced level of microbiota‐derived tryptophan metabolites. In summary, our findings substantiate the influential role of diet and environment in modulating the gut microbiota of red pandas, offering potential implications for improved captive breeding practices. [ABSTRACT FROM AUTHOR]

Simple Summary: Red pandas have evolved to become specialized bamboo eaters within Carnivora. Probably due to the difficulty in obtaining materials, reports on genes related to digestion and metabolism at expression and regulation levels in red pandas are rare. Red pandas and carnivorous mammal ferrets have a close phylogenetic relationship. They both consume highly nutritious milk during the suckling period, but consume low-energy bamboo and high-energy meat during the adult period, respectively. In order to explore the molecular mechanisms of dietary changes and nutrient utilization in red pandas, we discussed (1) the differences in expression changes of some genes related to digestion and metabolism in the stomach of these two species after food changes, as well as the expression adaptation of genes related to digestion and metabolism in both species during different feeding periods, and (2) the regulatory effects of lncRNAs and miRNAs on adaptive expressions of genes related to digestion and metabolism in both species from suckling to adult. Red pandas evolved from carnivores to herbivores and are unique within Carnivora. Red pandas and carnivorous mammals consume milk during the suckling period, while they consume bamboo and meat during the adult period, respectively. Red pandas and carnivorous mammal ferrets have a close phylogenetic relationship. To further investigate the molecular mechanisms of dietary changes and nutrient utilization in red pandas from suckling to adult, comparative analysis of the whole transcriptome was performed on stomach tissues from red pandas and ferrets during the suckling and adult periods. The main results are as follows: (1) we identified ncRNAs for the first time in stomach tissues of both species, and found significant expression changes of 109 lncRNAs and 106 miRNAs in red pandas and 756 lncRNAs and 109 miRNAs in ferrets between the two periods; (2) up-regulated genes related to amino acid transport regulated by lncRNA-miRNA-mRNA networks may efficiently utilize limited bamboo amino acids in adult red pandas, while up-regulated genes related to amino acid degradation regulated by lncRNAs may maintain the balance of amino acid metabolism due to larger daily intakes in adult ferrets; and (3) some up-regulated genes related to lipid digestion may contribute to the utilization of rich nutrients in milk for the rapid growth and development of suckling red pandas, while up-regulated genes associated with linoleic acid metabolism regulated by lncRNA-miRNA-mRNA networks may promote cholesterol decomposition to reduce health risks for carnivorous adult ferrets. Collectively, our study offers evidence of gene expression adaptation and ncRNA regulation in response to specific dietary changes and nutrient utilization in red pandas during suckling and adult periods. [ABSTRACT FROM AUTHOR]

The giant panda (Ailuropoda melanoleuca) and the Chinese red panda (Ailurus styani) are distributed in the same region in the mountain forest ecosystem on the eastern edge of the Qinghai Tibet Plateau and share the same food sources. In order to understand how sympatric giant pandas and Chinese red pandas maintain interspecific relationships to achieve stable coexistence, we used species distribution models and diurnal activity rhythms to analyze the spatial and temporal niche characteristics of giant pandas and Chinese red pandas in the Daxiangling Mountain system based on 187 camera traps data. The results show that: (1) In the Daxiangling Mountains, the total area of suitable habitats for giant pandas and Chinese red pandas is 717.61 km2 and 730.00 km2, respectively, accounting for 17.78% and 18.25%, respectively, of the study area. (2) The top five environmental factors contributing to the model of giant panda and Chinese red panda are precipitation seasonality, temperature seasonality, distance to the road, and elevation and vegetation type. (3) The total overlapping area of suitable habitats for giant pandas and Chinese red pandas is 342.23 km2, of which the overlapping area of highly suitable habitats is 98.91 km2. The overlapping index of suitable habitats is 0.472, and the overlapping index of highly suitable habitats is 0.348, which indicates that the two achieve spatial niches are separated to achieve stable coexistence. (4) The overlapping index of the daily activity rhythm of giant panda and Chinese red panda is 0.87, which is significantly different (p <.05). The existence of Chinese red panda will significantly affect the daily activity rhythm of giant panda (p <.001). This research can provide scientific reference for the researches about population and habitat protection of giant pandas and Chinese red pandas, so as to understand the driving mechanism of resource allocation and population dynamics of sympatric species. [ABSTRACT FROM AUTHOR]

Both the giant panda (Ailuropoda melanoleuca) and red panda (Ailurus fulgens) belong to the order Carnivora, but have changed their dietary habits to eating bamboo exclusively. The convergent evolution characteristics of their morphology, genome and gut flora have been found in the two pandas. However, the research on the convergent adaptation of their digestion and metabolism to the bamboo diet, mediated by the dietary shift of the two pandas at the gene-expression and epigenetic regulation levels, is still lacking. We therefore used RNA sequencing among five species (two pandas and three non-herbivore mammals) and bisulfite sequencing among three species (two pandas and a carnivore ferret) to sequence key digestion and metabolism tissues (stomach and small intestine). Our results provide evidence that the convergent differentially expressed genes (related to carbohydrate utilization, bile secretion, Lys and Arg metabolism, vitamin B12 utilization and cyanide detoxification) of the two pandas are adaptive responses to the bamboo diet containing low lipids, low Lys and Arg, low vitamin B12 and high cyanide. We also profiled the genome-wide methylome maps of giant panda, red panda and ferret, and the results indicated that the promoter methylation of the two pandas may regulate digestive and metabolic genes to adapt to sudden environmental changes, and then, transmit genetic information to future generations to evolve into bamboo eaters. Taken together, our study provides new insights into the molecular mechanisms of the dietary shift and the adaptation to a strict bamboo diet in both pandas using comparative transcriptomics and methylomics. [ABSTRACT FROM AUTHOR]

Endometrial mesenchymal stem cells (eMSCs) are undifferentiated endometrial cells with self-renewal, multidirectional differentiation and high proliferation potential. Nowadays, eMSCs have been found in a few species, but it has never been reported in endangered wild animals, especially the red panda. In this study, we successfully isolated and characterized the eMSCs derived from red panda. Red panda eMSCs were fibroblast-like, had a strong proliferative potential and a stable chromosome number. Pluripotency genes including Klf4 , Sox2 and Thy1 were highly expressed in eMSCs. Besides, cultured eMSCs were positive for MSC markers CD44, CD49f and CD105 and negative for endothelial cell marker CD31 and haematopoietic cell marker CD34. Moreover, no reference RNA-seq was used to analyse the eMSCs transcriptional expression profile and key pathways. Compared with skin fibroblast cell group, 9104 differentially expressed genes (DEGs) were identified, among which are 5034 genes upregulated, 4070 genes downregulated and the top 20 enrichment pathways of DEGs in Gene Ontology (GO) and the Kyoto Encyclopedia of Genes Genomes (KEGG) mainly associated with G-protein coupled receptor signalling pathway, carbohydrate derivative binding, nucleoside binding, ribosome biogenesis, cell cycle, DNA replication, Ras signalling pathway and purine metabolism. Among the DEGs, some representative genes about promoting MSCs differentiation and proliferation were upregulated and promoting fibroblasts proliferation were downregulated in eMSCs group. Red panda eMSCs also had multiple differentiation ability and could differentiate into adipocytes, chondrocytes and hepatocytes. In conclusion, we, for the first time, isolated and characterized the red panda eMSCs with ability of multiplication and multilineage differentiation in vitro. The new multipotential stem cell could be beneficial not only for the germ plasm resources conservation of red panda, but also for basic or pre-clinical studies in the future. [ABSTRACT FROM AUTHOR]

The red panda (Ailurus fulgens) has a similar diet, primarily bamboo, and shares the same habitat as the giant panda, Ailuropoda melanoleuca. There are considerable efforts underway to understand the ecology of the red panda and to increase its populations in natural reserves. Yet it is difficult to design an effective strategy for red panda reintroduction if we do not understand its basic biology. Here we report the resting metabolic rate of the red panda and find that it is higher than previously measured on animals from a zoo. The resting metabolic rate was 0.290 ml/g/h (range 0.204–0.342) in summer and 0.361 ml/g/h in winter (range 0.331–0.406), with a statistically significant difference due to season and test temperature. Temperatures in summer were probably within the thermal neutral zone for metabolism but winter temperatures were below the thermal neutral zone. There was no difference in metabolic rate between male and female red pandas and no difference due to mass. Our values for metabolic rate were much higher than those measured by McNab for 2 red pandas from a zoo. The larger sample size (17), more natural conditions at the Panda Base and improved accuracy of the metabolic instruments provided more accurate metabolism measurements. Contrary to our expectations based on their low quality bamboo diet, the metabolic rates of red pandas were similar to mammals of the same size. Based on their metabolic rates red pandas would not be limited by their food supply in natural reserves. [ABSTRACT FROM AUTHOR]

• The first report of BM-MSCs isolation, cultivation and identification in red pandas. • Red panda BM-MSCs showed fibroblast-like morphology and normal karyotype after culture. • BM-MSCs from red pandas were positive for MSC markers (CD44, CD105, CD90) and pluripotency genes (Oct4, Sox2 and Klf4). • Osteogenic, adipogenic and neuron-like cells were successfully induced from red panda BM-MSCs. Mesenchymal stem cells (MSC) have strong therapeutic potential due to their capacity for self-renewal and multilineage differentiation. MSCs can also be useful in preserving the current genetic diversity of endangered wildlife. To date, MSCs from various species have been studied, but only a few species of endangered wild animals have been reported. Adult bone marrow (BM) is a rich source of mesenchymal stem cells. The aim of this study was to isolate and characterize MSCs derived from the BM of red pandas. Red panda BM-MSCs isolated from five individuals were fibroblast-like cells, similar to other species. Cultured BM-MSCs with normal karyotype were negative for the hematopoietic line marker CD34 and the endothelial cell marker CD31 but were positive for MSC markers, including CD44, CD105 and CD90. RT-PCR and western blot analysis showed self-renewal and pluripotency genes, including Oct4, Sox2 and Klf4, were also expressed in red panda BM-MSCs. Finally, red panda BM-MSCs had the potential for differentiation into osteogenic, adipogenic and neuron-like cells by using a combination of previously reported protocols for other species. We have therefore demonstrated that cells harvested from red panda bone marrow are capable of extensive in vitro multiplication and multilineage differentiation, which is an essential step toward their use in the preservation of red pandas biological diversity and future studies on MSC applications in endangered species. [ABSTRACT FROM AUTHOR]