Climate change-induced food shortages pose major threats to wildlife conservation, and the exclusive reliance of giant pandas on bamboo makes them particularly vulnerable. The aim of this study was to provide insight into the reasons for the foraging strategies of giant pandas to selectively forage for different bamboo parts (bamboo shoot, culm, and leaf) during different seasons. This study used a metabolomic approach to analyze the fecal metabolites of giant pandas and conducted a correlation analysis with their gut microbiota. The results indicate that the fecal metabolites of giant pandas differ significantly depending on the bamboo parts they forage on, with higher sugar content observed when they consume bamboo culm with high fiber content. By functional annotation, culm group metabolites were enriched in the galactose metabolic pathway, while shoot group metabolites were enriched in the phenylalanine, tyrosine and tryptophan biosynthesis pathways. Moreover, Streptococcus showed a significant positive correlation with glucose and acetic acid content. Therefore, the foraging strategy of giant pandas is based on the ability to utilize the nutrient content of different bamboo parts. Captive feeding and habitat construction should enrich bamboo species to allow them to express their natural foraging strategies and improve their welfare and reproductive status.

Bamboo part preference plays a critical role in influencing the nutrient utilization and gastrointestinal microbiota composition of captive giant pandas. However, the effects of bamboo part consumption on the nutrient digestibility and gut microbiome of geriatric giant pandas remain unknown. A total of 11 adult and 11 aged captive giant pandas were provided with bamboo shoots or bamboo leaves in the respective single-bamboo-part consumption period, and the nutrient digestibility and fecal microbiota of both adult and aged giant pandas in each period were evaluated. Bamboo shoot ingestion increased the crude protein digestibility and decreased the crude fiber digestibility of both age groups. The fecal microbiome of the bamboo shoot-fed giant pandas exhibited greater alpha diversity indices and significantly different beta diversity index than the bamboo leaf-fed counterparts regardless of age. Bamboo shoot feeding significantly changed the relative abundance of predominant taxa at both phylum and genus levels in adult and geriatric giant pandas. Bamboo shoot-enriched genera were positively correlated with crude protein digestibility and negatively correlated with crude fiber digestibility. Taken together, these results suggest that bamboo part consumption dominates over age in affecting the nutrient digestibility and gut microbiota composition of giant pandas.

The impact of dietary microorganisms on host microbiota is recognized, but the underlying mechanisms remain unclear. This study examined the effects of bamboo surface microbiota, including virulence factors, antibiotic resistance genes (ARGs), and mobile genetic elements from different bamboo parts (leaves, shoots, and culms), on giant panda gut microbiota using three pairs of twins. Results showed that bamboo and fecal samples shared 1670 microbial species, with shoot surface microbiota contributing the highest proportion (21%, Bayesian source tracking) of contemporaneous gut microbiota, primarily by increasing abundances of Escherichia coli and ARGs. Klebsiella pneumoniae and Salmonella enterica also showed high co-occurrence in both bamboo and fecal samples, indicating potential colonization. Additionally, Streptococcus suis, Acinetobacter, and Mycobacterium progressively declined in fecal samples as bamboo shoot intake increased, suggesting these microbes are likely transient. The findings emphasize the impact of foodborne microorganisms on the host and the importance of conservation management.

The spread of antibiotic resistance genes (ARGs) in the environment exacerbates the contamination of these genes; therefore, the role plants play in the transmission of resistance genes in the food chain requires further research. Giant pandas consume different bamboo parts at different times, which provides the possibility of investigating how a single food source can affect the variation in the spread of ARGs. In this study, metagenomic analysis and the Comprehensive Antibiotic Resistance Database (CARD) database were used to annotate ARGs and the differences in gut microbiota ARGs during the consumption of bamboo shoots, leaves, and culms by captive giant pandas. These ARGs were then compared to investigate the impact of bamboo part consumption on the spread of ARGs. The results showed that the number of ARGs in the gut microbiota of the subjects was highest during the consumption of bamboo leaves, while the variety of ARGs was highest during the consumption of shoots. Escherichia coli, which poses a higher risk of ARG dissemination, was significantly higher in the leaf group, while Klebsiella, Enterobacter, and Raoultella were significantly higher in the shoot group. The ARG risk brought by bamboo shoots and leaves may originate from soil and environmental pollution. It is recommended to handle the feces of giant pandas properly and regularly monitor the antimicrobial and virulence genes in their gut microbiota to mitigate the threat of antibiotic resistance.

The objective of this study was to examine the macronutrient content in the shoots, leaves, and culms of bamboo species across various seasons within the habitats of wild giant pandas and in the cultivated regions for captive giant pandas. Results showed that crude protein (CP), fat, ash, and primary moisture (PM) contents of bamboo shoots were elevated, while there was a reduction in fiber content when compared to the leaves and culms ( p < 0.05). Nutritional composition varied among bamboo sources, with wild bamboo leaves exhibiting higher CP concentrations and lower fiber content ( p < 0.05), and higher CP and lower fiber in the bamboo of Xiangling mountains were observed. Almost all species exhibited greater concentrations of CP and PM and lower level of ash in annual bamboo leaves compared to the biennial and perennial ( p < 0.05). Moreover, as the bamboo culms matured, there was an increase in acid detergent lignin (ADL), soluble sugar (SS), starch, and gross energy (GE) ( p < 0.05). The ash, fiber, and GE contents were increased while the CP and SS were decreased both in leaves and culms among different bamboo species from spring to summer and fall. Moreover, Fargesia displayed lower PM, fiber, and ash levels compared to other species studied, and especially over 20% CP concentration was found in the annual leaves of Bashania spanostachya . These results indicated that macronutrient values of bamboo leaves and culms varied among species and were significantly influenced by the age of growth and seasonal changes.