Background: Snub-nosed monkeys are highly endangered primates and their population continues to decline with the habitat fragmentation. Artificial feeding and breeding is an important auxiliary conservation strategy. Studies have shown that changes and imbalances in the gut microbiota often cause gastrointestinal problems in captive snub-nosed monkeys. Here, we compare the gut microbiota composition, diversity, and predicted metabolic function of three endangered species of snub-nosed monkeys (Rhinopithecus bieti, R. brelichi, and R. roxellana) under the same captive conditions to further our understanding of the microbiota of these endangered primates and inform captive conservation strategies. 16 S rRNA gene sequencing was performed on fecal samples from 15 individuals (R. bieti N = 5, R. brelichi N = 5, R. roxellana N = 5). Results: The results showed that the three Rhinopithecus species shared 24.70% of their amplicon sequence variants (ASVs), indicating that the composition of the gut microbiota varied among the three Rhinopithecus species. The phyla Firmicutes and Bacteroidetes represented 69.74% and 18.45% of the core microbiota. In particular, analysis of microbiota diversity and predicted metabolic function revealed a profound impact of host species on the gut microbiota. At the genus level, significant enrichment of cellulolytic genera including Rikenellaceae RC9 gut group, Ruminococcus, Christensenellaceae R7 group, UCG 004 from Erysipelatoclostridiaceae, and UCG 002 and UCG 005 from Oscillospiraceae, and carbohydrate metabolism including propionate and butyrate metabolic pathways in the gut of R. bieti indicated that R. bieti potentially has a stronger ability to use plant fibers as energy substances. Bacteroides, unclassified Muribaculaceae, Treponema, and unclassified Eubacterium coprostanoligenes group were significantly enriched in R. brelichi. Prevotella 9, unclassified Lachnospiraceae, and unclassified UCG 010 from Oscillospirales UCG 010 were significantly enriched in R. roxellana. Among the predicted secondary metabolic pathways, the glycan biosynthesis and metabolism had significantly higher relative abundance in the gut of R. brelichi and R. roxellana than in the gut of R. bieti. The above results suggest that different Rhinopithecus species may have different strategies for carbohydrate metabolism. The Principal coordinate analysis (PCoA) and Unweighted pair-group method with arithmetic mean (UPGMA) clustering tree revealed fewer differences between the gut microbiota of R. brelichi and R. roxellana. Correspondingly, no differences were detected in the relative abundances of functional genes between the two Rhinopithecus species. Conclusion: Taken together, the study highlights that host species have an effect on the composition and function of the gut microbiota of snub-nosed monkeys. Therefore, the host species should be considered when developing nutritional strategies and investigating the effects of niche on the gut microbiota of snub-nosed monkeys.

Background: Gut microbiota exerts a pivotal function in host nutrient metabolism and maturation of the mucosal immunity. Analyzing the reciprocal interaction between horses and gut microbiota constitutes a crucial aspect of scientific feeding practices. This study aims to investigate the differences in gut microbiota among Hequ horses, Mongolian horses, and Thoroughbred horses, as well as between Thoroughbred horses at two age stages.Methods and results: Paired-end sequencing with a read length of 2×250 bp targeting the V3-V4 region of the 16S rRNA gene in fecal samples was carried out. Subsequently, differences in the diversity, composition, and metabolic pathways of the gut microbiota among the groups were analyzed. The results showed that: (1) Horse breeds were associated with variations in the gut microbiota. Microbial diversity, the proportion of commensal bacteria from Bacillota and Bacteroidota, and bacterial communities involved in dietary fiber metabolisms were significantly higher in the gut of the Hequ horses than in the gut of the Mongolian and Thoroughbred horses. The highest Bacillota to Bacteroidota (B/B) ratio and enrichment of bacterial communities involved in the metabolism of bile acids, lipids, and amino acids in the gut of the Mongolian horses resulted in significantly higher lipid metabolism and amino acid metabolism than in the other two breeds. The bacterial communities enriched in the gut of Thoroughbred horses were primarily involved in carbohydrate metabolism, but the level of energy metabolism was significantly lower than in Hequ horses. (2) The results also showed an association between age and gut microbiota of Thoroughbred horses. The alpha diversity, B/B ratio, and 83.33% of metabolic pathways did not differ significantly between younger and older Thoroughbred horses. However, there were significant differences between the two age groups in beta diversity, composition of glycolytic bacteria, metabolism of cofactors and vitamins, and energy metabolism of gut microbiota.Conclusions: Collectively, these results point to an association between the breed of horses or the age of Thoroughbred horses with variations in gut microbiota. The current findings will serve as a reference for improving feeding strategies for horses.

Background: Parasite infection and deworming treatment affect the host gut microbiota. Exploring the response mechanism of the gut microbiota in Rhinopithecus brelichi (R. brelichi) to albendazole deworming treatment is of great value for protecting this critically endangered species.Methods and results: This study used metataxonomics and metabolomics to explore the responses of the gut microbiota and metabolites of R. brelichi to albendazole deworming treatment. The results showed that deworming significantly reduced the eggs per gram of feces (EPG). The 16S rRNA gene sequencing results showed that the richness and diversity of the gut microbiota in R. brelichi after deworming were significantly increased. Meanwhile, deworming treatment also changed the composition of the gut microbiota. At the genus level, the Christensenellaceae R7 group, UCG 002, UCG 005, uncultured rumen bacterium, and Rikenellaceae RC9 gut group were significantly enriched in the pre-deworming samples. Unclassified Muribaculaceae, Prevotella 9, and Bacteroides were significantly enriched in the post-deworming samples. Metabolomics analysis revealed that the relative abundance of 382 out of 1,865 metabolites showed significant differences between the pre- and post-deworming samples. Among them, 103 metabolites were annotated based on the HMDB and mainly classified into Prenol lipids, Carboxylic acids and derivatives, and Organooxygen compounds, etc. The KEGG enrichment analysis result indicated that these metabolites were mainly involved in energy, amino acid, lipid, and purine metabolism. Correlation analysis showed that Bacteroides and unclassified Muribaculaceae, whose relative abundances were upregulated after deworming treatment, were positively correlated with Kaempferol, 5,7-Dihydroxy-3-methoxy-4′-prenyloxyflavone, Purpurin, and Rhein, which have anti-parasitic activities. The Christensenellaceae R7 group, with a downregulated relative abundance after deworming treatment, was not only negatively correlated with the above four metabolites, but also positively correlated with Retinyl beta-glucuronide, which is a storage form of vitamin A, and positively correlated with CDP-Choline, which increases the host’s susceptibility to Entamoeba histolytica and Plasmodium falciparum.Conclusion: This study emphasizes that deworming treatment has an impact on the gut microbiota and metabolic functions of R. brelichi. By exploiting the correlations between differential microbiota and metabolites, potential probiotics or prebiotics can be explored, thereby enhancing the efficiency of deworming and reducing its side effects.

The structure and composition of gut microbiota correlate with the occurrence and development of host health and disease. Diarrhea can cause alterations in gut microbiota in animals, and the changes in the gut microbial structure and composition may affect the development of diarrhea. However, there is a scarcity of information on the effects of diarrhea on gut fungal composition and structure, particularly in Baer's pochard (Aythya baeri). The current study was performed for high-throughput sequencing of the fungal-specific internal transcribed spacer 1 (ITS-1) to detect the differences of gut mycobiota in healthy and diarrheal Baer's pochard. Results showed that the gut mycobiota not only decreased significantly in diversity but also in structure and composition. Statistical analysis between two groups revealed a significant decrease in the abundance of phylum Rozellomycota, Zoopagomycota, Mortierellomycota, and Kickxellomycota in diarrheal Baer's pochard. At the genus levels, fungal relative abundance changed significantly in 95 genera, with 56 fungal genera, such as Wickerhamomyces, Alternaria, Penicillium, Cystofilobasidium, and Filobasidium, increasing significantly in the gut of the diarrheal Baer's pochard. In conclusion, the current study revealed the discrepancy in the gut fungal diversity and community composition between the healthy and diarrheal Baer's pochard, laying the basis for elucidating the relationship between diarrhea and the gut mycobiota in Baer's pochard.

Perinatal antibiotic exposure poses a significant risk to maternal-offspring immune programming and infant gut microbiota development. This study investigated the time-specific effects of maternal cefoperazone sodium (CPZ) administration on IgG transfer and offspring gut microbiota in a murine model. Pregnant C57BL/6J mice were assigned to control (CON), gestational (G-CPZ), lactational (L-CPZ), and combined gestational/lactational (GL-CPZ) treatment groups. Results showed that all CPZ treatments significantly reduced IgG and its subtype levels in maternal serum, colostrum, and offspring serum (p < 0.05). Concurrently, mRNA expression of the neonatal Fc receptor (FcRn), critical for IgG transport, was downregulated in both maternal breast and offspring intestinal tissues (p < 0.05). Furthermore, 16S rRNA sequencing revealed that CPZ exposure altered offspring gut microbiota diversity and composition. Alpha diversity was reduced, particularly in the G-CPZ group, while beta diversity showed significant separation in L-CPZ and GL-CPZ groups (p < 0.05). Taxonomic shifts included decreased Bacteroidetes and Lactobacillus, and in the GL-CPZ group, a marked increase in Firmicutes and potential pathobionts like Enterococcus and Hungatella (p < 0.05). These findings demonstrate that perinatal antibiotic exposure, depending on its timing, impairs maternal-offspring IgG transfer via the FcRn pathway and induces distinct, persistent alterations in the offspring’s gut microbiota, which may have implications for neonatal immunity and long-term health.