Differential Effects of Natural Grazing and Feedlot Feeding on Yak Fecal Microbiota

Comparative analysis of gut microbiota in free range and house fed yaks from Linzhou County

Gut microbiota variations in response to environmental and nutritional factors are of great significance as gut microbiota plays an integral role in nutrient metabolism, immunity, health, and disease conditions. In this context, limited studies investigated variations of gut microbiota in response to different feeding systems and environmental conditions. The current study obtained fresh fecal samples from house-fed (LS) and grazing yaks (LF) from Linzhou County. 16 S rRNA amplicon sequencing of the V3-V4 and internal transcribed spacer 2 (ITS2) domains generated 16,332 bacterial and 2345 fungus amplicon sequence variants (ASVs). Alpha and beta diversity indices revealed significant variations (p > 0.05) in gut microflora between the two groups. At the phylum level, Firmicutes, Actinobacteriota, Bacteroidota, and Patescibacteria regarding bacteria, and Ascomycota and Basidiomycota regarding fungi dominated. At the genus level, UCG-005, Rikenellaceae_RC9_gut_group, Clostridium_sensu_stricto_1, g__Muribaculaceae, UCG-010, [Eubacterium]_coprostanoligenes_group, Turicibacter, Alistipes, Prevotellaceae_UCG-003, UCG-009, Blautia, dgA-11_gut_group, Candidatus_Saccharimonas dominated in LS, while Anthrobacter and Terrisporobacter dominated in the LF group. Fungal genera like Myrothecium and Plectosphaerella dominated the LS group, while Neoascochyta, Paraphaeosphaeria, and Hypocreales dominated the LF group. Also, significant variations (p > 0.05) in gene expressions were found between the two groups. These findings provide insights into yak gut microbiota adaptations and metabolic changes in response to varied environmental conditions and can provide valuable information, optimizing feeding strategies after identifying specific differences between grazing and house-fed yaks, reducing environmental impacts, and improving yaks' health and productivity in specific geographical settings.

Comparative analysis of the fecal microbiota in Père David's deer and five other captive deer species

Introduction

Gut microbes are essential for host nutrition, immunity, and development. Various factors influence the composition and function of the gut microbial community. However, there is limited knowledge regarding the comparison of gut microbiota across different deer species, particularly those in the World Deer Park of Baotou (Inner Mongolia, China).

Methods

This study utilized 16S rRNA gene amplicon sequencing to analyze the fecal microbiota and potential microbial function in Père David's Deer (Elaphurus davidianus), Sika deer (Cervus nippon), American Wapiti (Cervus canadensis), Red Deer (Cervuselaphus), Fallow Deer (Dama dama), and Reindeer (Rangifer tarandus).

Results and discussion

The findings indicated no significant differences in alpha diversity, yet there was a noteworthy distinction in beta diversity among the six deer groups. At the phylum level, the predominant bacteria in the deer populations were Firmicutes, Bacteroidetes, and Proteobacteria. At the genus level, 54 core bacterial microbiota were identified. The top four genera in AW, FD, PD, and SD were Ruminococcaceae UCG-005, Rikenellaceae RC9 gut group, RuminococcaceaeUCG-010 and Christensenellaceae R-7 group. The results of the neutral model revealed that neutral processes predominantly governed the gut microbiota community assembly in different deer species, particularly in Père David's deer. PICRUSt2 predictions showed significant enrichment of fecal bacterial functions related to fatty acid, lipid, metabolic regulator, and amino acid biosynthesis. This comparative analysis sheds light on the microbial community structure, community assembly, and potential functions, offering improved insights into the management and conservation of deer species, especially Père David's deer. Future research might focus on exploring metagenomic functions and dynamics in wild settings or across different seasons using metagenomics or metatranscriptomics.

Gut microbiome reveals the trophic variation and significant adaption of three sympatric forest-dwelling ungulates on the eastern Qinghai-Xizang Plateau

BACKGROUND

The gut microbiome of herbivorous mammals regulates numerous physiological processes, including digestion and energy metabolism. The complex stomach architecture of ruminants, in conjunction with the metabolic capabilities of their microbiota, confers a considerable adaptive advantage to these animals. Nevertheless, a significant gap persists in comparative studies on the variations in the gut microbiome among sympatric ruminants and their potential adaptive implications. Accordingly, in this study, 16S rRNA gene sequencing and metagenomic approaches were used to analyse the composition and functional attributes of the gut microbiome of sympatric Moschus chrysogaster, Capricornis sumatraensis, and Cervus albirostris inhabiting the eastern periphery of the Qinghai-Xizang Plateau.

RESULTS

The gut microbiome of C. albirostris exhibited a higher diversity than that of M. chrysogaster and C. sumatraensis, whereas those of M. chrysogaster and C. sumatraensis were similar. Although species-specific variations existed among the three mammalian microbiomes, the microbiomes of C. albirostris and C. sumatraensis were more similar, whereas that of M. chrysogaster was markedly distinct. Metagenomic analysis revealed a pattern of functional convergence in the gut microbiome of the three species, with the gut microbiome of C. albirostris exhibiting a pronounced emphasis on carbohydrate metabolism, significantly surpassing that of M. chrysogaster and C. sumatraensis. Compared to the other two species, the gut microbiome of C. sumatraensis presented significantly elevated levels of amino acids and energy metabolism, whereas that of M. chrysogaster presented an increased capacity for 3-hydroxyacyl- [acyl carrier protein]-dehydratase production.

CONCLUSION

These findings suggest that the gut microbiome of sympatric M. chrysogaster, C. sumatraensis, and C. albirostris tend to converge. Metabolic variations within their gut microbiome may result in differential food resource utilisation, potentially indicating significant nutritional and ecological trait characteristics for stable coexistence.

A lysing polysaccharide monooxygenase from Aspergillus niger effectively facilitated rumen microbial fermentation of rice straw

OBJECTIVE

This study investigated the impact of Aspergillus niger lysing polysaccharide monooxygenase (AnLPMO) on in vitro rumen microbial fermentation of rice straw.

METHODS

AnLPMO was heterologously expressed in Escherichia coli. Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy analyzed the surface structure of rice straw after AnLPMO treatment. Two in vitro experiments, coupled with 16S highthroughput sequencing and quantitative real-time polymerase chain reaction techniques, assessed the influence of AnLPMO on rumen microbial fermentation of rice straw.

RESULTS

AnLPMO exhibited peak activity at 40°C and pH 6.5, with a preference for rice straw xylan hydrolysis, followed by Avicel. AnLPMO application led to the fractional removal of cellulose and hemicelluloses and a notable reduction in the levels of carbon elements and C-C groups present on the surface of rice straw. Compared to the control (no AnLPMO), supplementing AnLPMO at 1.1 to 2.0 U significantly enhanced in vitro digestibility of dry matter (IVDMD, p<0.01), total gas production (p<0.01), and concentrations of total volatile fatty acids (VFA, p<0.01), acetate (p<0.01), and ammonia-N (p<0.01). Particularly, the 1.4 U AnLPMO group showed a 14.8% increase in IVDMD. In the second experiment, compared to deactivated AnLPMO (1.4 U), supplementing bioactive AnLPMO at 1.4 U increased IVDMD (p = 0.01), total gas production (p = 0.04), and concentrations of total VFA (p<0.01), propionate (p<0.01), and ammonia-N (p<0.01), with a limited 9.6% increase in IVDMD. Supplementing AnLPMO stimulated the growth of ruminal bacterial taxa facilitating fiber degradation, including Proteobacteria, Spirochaetes, Succinivibrio, Rikenellaceae_RC9_ Gut_Group, Prevotelaceae_UCG-003, Desulfovibrio, Fibrobacter succinogenes, Ruminococcus albus, R. flavefaciens, Prevotella bryantii, P. ruminicola, and Treponema bryantii.

CONCLUSION

These findings highlight AnLPMO's potential as a feed additive for improving rice straw utilization in ruminant production.

Gut Microbial Adaptation to Varied Altitudes and Temperatures in Tibetan Plateau Yaks

The yak (Bos grunniens) exhibits exceptional regional adaptability, enabling it to thrive in the distinctive ecological niches of the Qinghai-Tibet Plateau. Its survival relies on the intricate balance of its intestinal microbiome, essential for adapting to harsh environmental conditions. Despite the documented significance of bacteria and fungi in maintaining intestinal homeostasis and supporting immune functions, there is still a substantial gap in understanding how the composition and functionality of yak gut microbiota vary along altitude-temperature gradients. This study aims to fill this gap by employing 16S rRNA and ITS amplicon sequencing techniques to analyze and compare the intestinal microbiome of yaks residing at different elevations and exposed to varying temperatures. The findings demonstrate subtle variations in the diversity of intestinal bacteria and fungi, accompanied by significant changes in taxonomic composition across various altitudes and temperature gradients. Notably, Firmicutes, Actinobacteriota, and Bacteroidota emerged as the dominant phyla across all groups, with Actinobacteriota exhibiting the highest proportion (35.77%) in the LZF group. Functional prediction analysis revealed significant associations between the LZF group and metabolic pathways related to amino acid metabolism and biosynthesis. This suggests a potential role for actinomycetes in enhancing nutrient absorption and metabolism in yaks. Furthermore, our findings suggest that the microbiota of yaks may enhance energy metabolism and catabolism by modulating the Firmicutes-to-Bacteroidota ratio, potentially mitigating the effects of temperature variations. Variations in gut bacterial and fungal communities among three distinct groups were analyzed using metagenomic techniques. Our findings indicate that microbial genera exhibiting significant increases in yaks at lower altitudes are largely beneficial. To sum up, our research investigated the changes in gut bacterial and fungal populations of yaks residing across diverse altitude and temperature ranges. Moreover, these results enhance comprehension of gut microbial makeup and variability, offering perspectives on the environmental resilience of dry lot feeding yaks from a microbial angle.

Yaks Are Dependent on Gut Microbiota for Survival in the Environment of the Qinghai Tibet Plateau

The yak (Poephagus grunniens) has evolved unique adaptations to survive the harsh environment of the Qinghai-Tibetan Plateau, while their gut microorganisms play a crucial role in maintaining the health of the animal. Gut microbes spread through the animal population not only by horizontal transmission but also vertically, which enhances microbial stability and inheritance between generations of the population. Homogenization of gut microbes in different animal species occurs in the same habitat, promoting interspecies coexistence. Using the yak as a model animal, this paper discusses the adaptive strategies under extreme environments, and how the gut microbes of the yak circulate throughout the Tibetan Plateau system, which not only affects other plateau animals such as plateau pikas, but can also have a profound impact on the health of people. By examining the relationships between yaks and their gut microbiota, this review offers new insights into the adaptation of yaks and their ecological niche on the Qinghai-Tibetan plateau.

Fecal microbiota transplants modulate the gut microbiome of a two-toed sloth (Choloepus didactylus)

The microbes inhabiting an animal's gastrointestinal tracts, collectively known as the gut microbiome, are vital to animal health and wellbeing. For animals experiencing gut distress or infection, modulation of the gut microbiome, for example, via fecal microbiota transplant (FMT), provides a possible disease prevention and treatment method. The beneficial microbes present in the donor's transplanted feces can help combat pathogens, assist in digestion, and rebalance the recipient's microbiota. Investigating the efficacy of FMTs in animal health is a crucial step toward improving management strategies for species under human care. We present a case study of the use of FMTs in a two-toed sloth experiencing abnormally large, clumped, and frequent stools. We used 16 S rRNA amplicon sequencing of fecal samples to (a) compare the microbiomes of the FMT donor, a healthy, cohoused conspecific, and the FMT recipient and (b) assess the influence of multiple rounds of FMTs on the recipient's microbiome and stool consistency and frequency over time. In response to the FMTs, we found that the recipient's microbiome showed trends toward increased diversity, shifted community composition, and altered membership that more resembled the community of the donor. FMT treatment was also associated with marked, yet temporary, alleviation of the recipient's abnormal bowel movements, suggesting a broader impact on gut health. Our results provide valuable preliminary evidence that FMT treatments can augment the recipient's gut microbiome, with potential implications for animal health and management.

Microbiota and Serum Metabolic Profile Changes in Korean Native Hanwoo Steer in Response to Diet Feeding Systems

The diversity of bacteria and their function in cattle gastrointestinal tracts can influence animal welfare. Next-generation sequencing (NGS) was used to investigate microbial diversity in the feces of Hanwoo steers reared under natural grazing (GS) and housing (HS) systems. Additionally, serum metabolic parameters, such as liver and kidney markers and mineral and lipid content changes, as well as their correlation with pyrotags, were studied. A total of 6468 ± 87.86 operational taxonomic units (OTUs) were identified in both steer groups, of which 3538 ± 38.17 OTUs were from grazing steer and 2930 ± 94.06 OTUs were from GS. Chao1 index analysis revealed a higher bacterial richness in GS. The dominant bacterial taxa were Bacteroidetes and Firmicutes. GS showed lower Bacteroidetes and higher Firmicutes abundance than HS. The serum of HS showed consistent increases in gamma-glutamyl transpeptidase (γGTP), glucose (GLU), total cholesterol (T-CHO), and triglyceride (TG) levels. The impact of GS on animal health and serum metabolic markers was strongly correlated with microbiota. As shown in this study, grazing has a significant impact on the fecal microbiota at the phylum and family levels, as well as the serum biochemical metabolites of Hanwoo steers.