Search

During the adaptive evolution of animals, the host and its gut microbiota co-adapt to different elevations. Currently, there are few reports on the rumen microbiota–hepato-intestinal axis of Tibetan sheep at different altitudes. Therefore, the purpose of this study was to explore the regulatory effect of rumen microorganism–volatile fatty acids (VFAs)–VFAs transporter gene interactions on the key enzymes and genes related to gluconeogenesis in Tibetan sheep. The rumen fermentation parameters, rumen microbial densities, liver gluconeogenesis activity and related genes were determined and analyzed using gas chromatography, RT-qPCR and other research methods. Correlation analysis revealed a reciprocal relationship among rumen microflora–VFAs-hepatic gluconeogenesis in Tibetan sheep at different altitudes. Among the microbiota, Ruminococcus flavefaciens (R. flavefaciens), Ruminococcus albus (R. albus), Fibrobactersuccinogenes and Ruminobacter amylophilus (R. amylophilus) were significantly correlated with propionic acid (p < 0.05), while propionic acid was significantly correlated with the transport genes monocarboxylate transporter 4 (MCT4) and anion exchanger 2 (AE2) (p < 0.05). Propionic acid was significantly correlated with key enzymes such as pyruvate carboxylase, phosphoenolpyruvic acid carboxylase and glucose (Glu) in the gluconeogenesis pathway (p < 0.05). Additionally, the expressions of these genes were significantly correlated with those of the related genes, namely, forkhead box protein O1 (FOXO1) and mitochondrial phosphoenolpyruvate carboxykinase 2 (PCK2) (p < 0.05). The results showed that rumen microbiota densities differed at different altitudes, and the metabolically produced VFA contents differed, which led to adaptive changes in the key enzyme activities of gluconeogenesis and the expressions of related genes. [ABSTRACT FROM AUTHOR]

Simple Summary: The gut microbiota plays an important role in animals. Metabolomics analysis was used in this study to investigate the rumen microbiota density and metabolome interactions in lambs supplemented with Astragalus root powder; the density of the rumen microbiota and its relationship with the metabolome in lambs supplemented with Astragalus root powder were evaluated. The results showed a significant correlation between the rumen microbiota and its metabolome in lambs. These findings have important implications for livestock nutrition and management practices, particularly in terms of improving overall productivity and profitability. The gut microbiota is highly symbiotic with the host, and the microbiota and its metabolites are essential for regulating host health and physiological functions. Astragalus, as a feed additive, can improve animal immunity. However, the effects of Astragalus root powder on the rumen microbiota and their metabolites in lambs are not apparent. In this study, thirty healthy Hu sheep lambs with similar body weights (17.42 ± 2.02 kg) were randomly selected for the feeding experiment. Lambs were fed diets supplemented with 0.3% Astragalus root powder, and the rumen microbiota density and metabolome were measured to determine the effects of Astragalus on the health of lambs in the rumen. The results showed that the relative abundance of Butyrivibrio fibrisolvens (Bf), Ruminococcus flavefaciens (Rf), Succiniclasticum (Su), and Prevotella (Pr) in the rumen was increased in the Astragalus group (p < 0.01), and metabolic profiling showed that the metabolites, such as L-lyrosine and L-leucine, were upregulated in the Astragalus group (p < 0.01). KEGG functional annotation revealed that upregulated metabolites were mainly enriched in the pathways of amino acid metabolism, lipid metabolism, fatty acid biosynthesis, and bile secretion in the Astragalus group, and downregulated metabolites were enriched in the pathways of methane metabolism and other pathways. Correlation analysis revealed that butyric acid was positively correlated with Roseburia and Blautia (p < 0.05) and negatively correlated with Desulfovibrio (p < 0.05). Thus, by analyzing the interactions of Astragalus root powder with the density of rumen microorganisms and their metabolites in lambs, it was shown that Astragalus root powder could improve the structure of rumen microbiota and their metabolites and then participate in the regulation of amino acid metabolism, lipid metabolism, immune metabolism, and other pathways to improve the efficiency of energy absorption of the lambs. [ABSTRACT FROM AUTHOR]

Simple Summary: In the context of large-scale production, it is necessary to improve ewes health status and reproductive performance to promote newborns survival rate and later fattening performance. Previous studies have indicated that phenolic acids could change the host rumen microflora and inhibit pathogenic bacteria to ensure rumen health and host body health. However, there are few studies on isochlorogenic acid (ICGA) in ruminants. Therefore, based on regulating the rumen environment of breeding ewes during the whole physiological period, the experiment was conducted to study the effects of ICGA on rumen fermentation, microbial diversity and immunity of ewes at estrus, pregnancy and lactation stages. The experimental data obtained showed that adding ICGA could regulate ewes rumen fermentation mode, optimize microbial flora of different physiological stages by increasing Bacteroidota relative abundance while reducing Firmicutes relative abundance, maintain rumen microbial homeostasis at the pregnancy stage, and increase ewes blood immuneglobulin content, thereby improving ewes health. The effects of isochlorogenic acid (ICGA) on ewes rumen environment, microbial diversity, and immunity at different physiological stages (estrus, pregnancy and lactation) were studied in this experiment. Twenty healthy female Hu lambs of 1.5 months with similar body weight (17.82 ± 0.98 kg) and body condition were selected and randomly divided into two groups: the control group (CON) and the ICGA group (ICGA). The lambs of CON were fed a basal diet, while the lambs of ICGA were supplemented with 0.1% ICGA based on the basal diet. Lambs rumen fermentation characteristics, microbial diversity and immunity at estrus, pregnancy, and lactation stages were determined and analyzed, respectively. The results showed that the rumen pH in CON increased first and then decreased as lambs grew (p < 0.05). However, it showed the opposite change in ICGA. The content of ammonia nitrogen (NH3-N) showed the highest at estrus stage in both groups, but it was significantly higher in ICGA than that in CON (p < 0.05). The Acetic acid/propionic acid (A/P) ratio at estrus stage and the volatile fatty acids (VFAs) at pregnancy stage in ICGA were significantly higher than those of the CON (p < 0.05). The 16S rDNA sequencing analysis showed that the Shannon, Chao 1 and ACE indexes of the ICGA were significantly higher than those of the CON both at estrus and lactation stages (p < 0.05), while they showed higher at the pregnancy stage in CON (p > 0.05). Principal component analysis (PCA) showed that there were significant differences in rumen microorganism structure between CON and ICGA at all physiological stages (p < 0.01). At the phylum level, compared with the CON, Firmicutes relative abundance of three physiological stages decreased (p > 0.05) while Bacteroidota increased (p > 0.05). The relative abundance of Synergistota at estrus stage and Patescibacteria at the lactation stage increased significantly too (p < 0.05). At the genus level, compared with the CON, the relative abundance of Prevotella at three stages showed the highest (p > 0.05), while the relative abundance of Succiniclasticum, unclassified_Selenomonadaceae and Rikenellaceae_RC9_gut_group showed different abundances at different physiological stages in ICGA. Compared with the CON, the lambs of the ICGA showed higher blood IgG, IgM, and TNF- α contents at three physiological stages and higher IL-6 contents at pregnancy stage (p < 0.05). Conclusion: Adding ICGA could regulate ewes rumen fermentation mode at different physiological stages by increasing rumen NH3-N at estrus, VFAs at pregnancy, and the ratio of A/P at lactation. It optimizes rumen microbial flora of different physiological stages by increasing Bacteroidota relative abundance while reducing Firmicutes relative abundance, maintaining rumen microbial homeostasis at pregnant stage, increasing the number of beneficial bacteria in later lactating and ewes blood immunoglobulins content at three physiological stages. [ABSTRACT FROM AUTHOR]

Altitude is the main external environmental pressure affecting the production performance of Tibetan sheep, and the adaptive evolution of many years has formed a certain response mechanism. However, there are few reports on the response of ruminal microbiota and host genomes of Tibetan sheep to high-altitude environments. Here, we conducted an integrated analysis of volatile fatty acids (VFAs), microbial diversity (16S rRNA), epithelial morphology, and epithelial transcriptome in the rumen of Tibetan sheep at different altitudes to understand the changes in ruminal microbiota–host interaction in response to high altitude. The differences in the nutritional quality of forage at different altitudes, especially the differences in fiber content (ADF/NDF), led to changes in rumen VFAs of Tibetan sheep, in which the A/P value (acetic acid/propionic acid) was significantly decreased (p < 0.05). In addition, the concentrations of IgA and IgG in Middle-altitude (MA) and High-altitude Tibetan sheep (HA) were significantly increased (p < 0.05), while the concentrations of IgM were significantly increased in MA (p < 0.05). Morphological results showed that the width of the rumen papilla and the thickness of the basal layer increased significantly in HA Tibetan sheep (p < 0.05). The 16S rRNA analysis found that the rumen microbial diversity of Tibetan sheep gradually decreased with increasing altitude, and there were some differences in phylum- and genus-level microbes at the three altitudes. RDA analysis found that the abundance of the Rikenellaceae RC9 gut group and the Ruminococcaceae NK4A214 group increased with altitudes. Furthermore, a functional analysis of the KEGG microbial database found the "lipid metabolism" function of HA Tibetan sheep to be significantly enriched. WGCNA revealed that five gene modules were enriched in "energy production and conversion", "lipid transport and metabolism", and "defense mechanisms", and cooperated with microbiota to regulate rumen fermentation and epithelial immune barrier function, so as to improve the metabolism and immune level of Tibetan sheep at high altitude. [ABSTRACT FROM AUTHOR]

Background: The gut microbiota play an important role in maintaining host metabolism, the immune system and health, while sex, genotype, diet and health have specific effects on the composition of the gut microbiota. Therefore, to explore the sex differences in the structure and function of rumen microbiota in Tibetan goats, herein we analyzed sex differences in rumen fermentation parameters, rumen microbiota and the expression of genes related to VFA transport in Tibetan goats. Results: The results showed that the contents of acetic acid and propionic acid in the rumen of TGM (Tibetan goat male) were significantly higher than those in TGFm (Tibetan goat female) (P < 0.05), and total VFAs was significantly higher in TGM than TGFm (P < 0.05). Expression of the VFA transport-related genes DRA, AE2, MCT-1, NHE1, and NHE2 in the rumen epithelium of TGFm was significantly higher than that in TGM. Analysis of the composition and structure of the rumen microbiota revealed significant sex differences. At the phylum level, Firmicutes and Bacteroidetes were the dominant phyla in Tibetan goats. In addition, Fibrobacteres and Spirochaetes had significantly greater relative abundances in TGFm than in TGM (P < 0.05). At the genus level, the relative abundance of Fibrobacter, Ruminococcus_1 and Pyramidobacter was significantly higher in TGFm than in TGM (P < 0.05). The functional prediction results showed that replication, recombination and repair, RNA processing and modification were mainly enriched in TGFm (P < 0.05). Conclusions: Correlation analysis revealed significant associations of some rumen microbiota with the fermentation product VFAs and VFA transport-related genes. We concluded that yearling TGM and TGFm have distinct fermentation and metabolism abilities when adapting to the plateau environment, which provides a certain sex reference basis for Tibetan goat adaptation to the plateau environment. [ABSTRACT FROM AUTHOR]

As one of the important ruminants of the Qinghai-Tibet Plateau, Tibetan sheep are able to reproduce and maintain their population in this harsh environment of extreme cold and low oxygen. However, the adaptive mechanism of Tibetan sheep when nutrients are scarce in the cold season of the Plateau environment is unclear. We conducted comparative analysis rumen fermentation parameters, rumen microbes, and expression of host genes related to nutrient absorption and rumen epithelial barrier function in cold and warm season Tibetan sheep. We found that concentrations of the volatile fatty acids (VFAs) acetate, propionate and butyrate of Tibetan sheep in the cold season were significantly higher than in the warm season (P < 0.05). Microbial 16S rRNA gene analysis revealed significant differences in rumen microbiota between the cold and warm seasons, and the abundance of microbial in the cold season was significantly higher than that in the warm season (P < 0.05), and the lack of nutrients in the cold season led to a significant reduction in the expression of SGLT1 , Claudin-4 , and ZO-1 genes in the rumen epithelium. Correlation analysis revealed significant associations of some rumen microorganisms with the fermentation product acetate and the rumen epithelial genes SGLT1 , Claudin-4 , and ZO-1. [ABSTRACT FROM AUTHOR]

Simple Summary: The Qinghai-Tibet Plateau has a unique ecological environment, involving high altitude, low oxygen levels, strong ultraviolet rays, and severe imbalances in seasonal forage supply, which poses a serious threat to the livestock that feeds on natural pastures to maintain their survival. We have carried out a long-term follow-up study on rumen fermentation characteristics, the microbiota, and rumen epithelial gene expression of local Tibetan sheep. Correlation analysis showed that there were interactions among rumen fermentation characteristics, the microbiota, and host gene expression, mainly by adjusting the amino acid metabolism pathway and energy metabolism pathway to improve energy utilization. At the same time, we adjusted the balance of the rumen "core microbiota", which was regulated to promote the development of rumen and maintain the homeostasis of rumen environment (which relies Tibetan sheep can better adapt to the harsh environment in different periods of the Qinghai-Tibet Plateau). This provides a theoretical basis for the breeding and management of Tibetan sheep on the Qinghai-Tibet Plateau. As an important ruminant on the Qinghai-Tibet Plateau, Tibetan sheep can maintain their population reproduction rate in the harsh high-altitude environment of low temperature and low oxygen, which relies on their special plateau adaptations mechanism that they have formed for a long time. Microbiomes (known as "second genomes") are closely related to the nutrient absorption, adaptability, and health of the host. In this study, rumen fermentation characteristics, the microbiota, and rumen epithelial gene expression of Tibetan sheep in various months were analyzed. The results show that the rumen fermentation characteristics of Tibetan sheep differed in different months. The total SCFAs (short-chain fatty acids), acetate, propionate, and butyrate concentrations were highest in October and lowest in June. The CL (cellulase) activity was highest in February, while the ACX (acid xylanase) activity was highest in April. In addition, the diversity and abundance of rumen microbes differed in different months. Bacteroidetes (53.4%) and Firmicutes (27.4%) were the dominant phyla. Prevotella_1 and Rikenellaceae_RC9_gut_group were the dominant genera. The abundance of Prevotella_1 was highest in June (27.8%) and lowest in December (17.8%). In addition, the expression of CLAUDIN4 (Claudin-4) and ZO1 (Zonula occludens 1) was significantly higher in April than in August and December, while the expression of SGLT1 (Sodium glucose linked transporter 1) was highest in August. Correlation analysis showed that there were interactions among rumen fermentation characteristics, the microbiota, and host gene expression, mainly by adjusting the amino acid metabolism pathway and energy metabolism pathway to improve energy utilization. At the same time, we adjusted the balance of the rumen "core microbiota" to promote the development of rumen and maintain the homeostasis of rumen environment, which makes Tibetan sheep better able to adapt to the harsh environment in different periods of the Qinghai-Tibet Plateau. [ABSTRACT FROM AUTHOR]