Introduction: The mutton quality of Chinese Tan lambs (Ovis aries) has declined as feeding patterns have shifted from pasturing to pen rationing. While pen-fed can enhance the growth performance of sheep, it falls short in terms of meat quality attributes such as meat color and tenderness. Furthermore, compared to pen-fed, pasture-fed husbandry increases the proportion of oxidative muscle fibers, decreases the proportion of glycolytic muscle fibers, and reduces LDH (lactate dehydrogenase) activity. Mutton quality is affected by fatty acids, and rumen microorganisms play a role in the synthesis of short-chain fatty acids, long-chain fatty acids, and conjugated linoleic acids.Methods: We used 16S rRNA sequencing to analyze the effects of two feeding patterns on the rumen bacteria of Tan lambs. In a randomized block design with 24 newborn Tan lambs, 12 lambs were fed by ewes in pasture and 12 were fed by pen-fed ewes. At 2 months, the biceps femoris and the longissimus dorsi were analyzed by gas chromatography for intramuscular fat content and fatty acids composition, and DNA in the rumen contents was extracted and used to analyze the structure of the bacterial community.Results: Different feeding patterns had no significant effect on the intramuscular fat content of the biceps femoris and longissimus dorsi of the lambs, but there was a significant effect on fatty acids composition. The fatty acids c18:3n3 and c20:5n3 were significantly higher in the biceps femoris and longissimus dorsi of the pasture group than the pen-ration group. The alpha diversity of rumen bacteria was significantly greater in the pasture group compared to the pen-ration group. The ACE index, Chao1 index, Shannon index, and Simpson index were all notably higher in the pasture group than in the pen-ration group. Utilizing beta diversity analysis to examine the differences in rumen bacteria between the pasture group and pen-ration group, it was observed that the homogeneity of bacteria in the pasture group was lower than that in the pen-ration group. Furthermore, the diversity of rumen bacteria in the pasture group was greater than that in the pen-ration group. Twenty-one phyla were identified in the pasture group, and 14 phyla were identified in the pen-ration group. The dominant phyla in the pasture group were Bacteroidetes and Fibrobacteres; the dominant phyla in the pen-ration group were Proteobacteria and Bacteroidetes. The relative abundance of Proteobacteria was significantly higher in the pen-ration group than in the pasture group (p < 0.01). Diversity at the genus level was also higher in the pasture group, with 176 genera in the pasture group and 113 genera in the pen-ration group. The dominant genera in the pasture group were Prevotella_1, Rikenellaceae_RC9_gut_group, and Bacteroidales_BS11_gut_group_Na; the dominant genera in the pen-ration group were Prevotella_1, Prevotella_7, Succinivibrionaceae_UCG-001, and Succinivibrionaceae_NA.Discussion: The rumen bacterial community of Tan sheep is significantly influenced by pen-ration and pasture-fed conditions, leading to variations in fatty acid content in the muscle, which in turn affects the flavor and nutritional value of the meat to some extent. Pasture-fed conditions have been shown to enhance the diversity of rumen bacterial community structure in Tan sheep, thereby increasing the nutritional value of their meat.

We evaluated the difference between rumen bacteria in Tan sheep fed either by grazing or in a feedlot. The aim was to provide a theoretical basis for ruminant nutrition and meat quality based on rumen fermentation. Twenty-four three-month-old Tan sheep were randomly and equally divided into two groups, the grazing group and ration group. Five sheep of each group were selected for slaughter at six months of age. Ruminal contents were collected and assessed to identify rumen bacteria, based [...] ABSTRACT We evaluated the difference between rumen bacteria in Tan sheep fed either by grazing or in a feedlot. The aim was to provide a theoretical basis for ruminant nutrition and meat quality based on rumen fermentation. Twenty-four three-month-old Tan sheep were randomly and equally divided into two groups, the grazing group and ration group. Five sheep of each group were selected for slaughter at six months of age. Ruminal contents were collected and assessed to identify rumen bacteria, based

Alkaline mineral complex buffer can improve rumen fermentation and affect the rumen microbiota of dairy cows. Here, we studied the effects of alkaline mineral complex buffer on serum immunity indexes, rumen fermentation and the microbiota of newborn calves. We also investigated changes in the rumen epithelial transcriptome expression profile. Compared with the control group, at 15 d, the serum contents of TP and GLB in the treatment group increased significantly (p < 0.05). At 30 d, the serum contents of GLB in the treatment group increased significantly (p < 0.05). At 45 d, the serum contents of IgG in the treatment group increased significantly (p < 0.05). At 60 d, the serum contents of TP and IgG in the treatment group increased significantly (p < 0.05). Rumen pH in the treatment groups was significantly increased at different days of age (p < 0.05). The microbial community composition in the rumen was determined using bacterial and archaeal 16S ribosomal RNA (rRNA) gene amplicon-sequencing. Analysis of bacterial composition in the rumen showed that there was no significant difference in bacterial diversity (p > 0.05). At the phylum level, Firmicutes were significantly decreased and Bacteroidetes were significantly increased in the treatment group at 30 d (p < 0.05). At the genus level, Prevotella_1, Olsenella, Christensenellaceae_R-7_group were significantly increased, and Lachnospiraceae_NK3A20_group, Ruminococcaceae_UCG-014 and Ruminococcus_2 were significantly decreased in the treatment group at 30 d (p < 0.05). Christensenellaceae_R-7_group was significantly increased in the treatment group (p < 0.05) at 45 d. Prevotella_9 was significantly decreased, and Prevotellaceae_UCG_001, Christensenellaceae_R-7_group were significantly increased in the treatment group at 60 d (p < 0.05). RNA sequence analysis of the rumen epithelium showed that 232 differentially expressed genes were screened, of which 158 were upregulated and 74 were downregulated. The main enrichment pathway was related to immune regulation. In conclusion, alkaline mineral complex buffer can enhance the body’s immune response, regulate rumen fermentation by regulating the abundance of rumen microbiota and upregulate immune-related genes in rumen tissues to promote immune regulation. The results of this study provide a reference for the early nutritional regulation of newborn calves with an alkaline mineral complex buffer.

The purpose of this study was to investigate the effects of replacing a portion of whole-plant corn silage with straw on the rumen microbial community structure and carbohydrate-active enzyme activity. The experiment employed a single-factor randomized trial design, with eight late-lactation Chinese Holstein dairy cows being randomly divided into two groups of four replicates each. The control group (CS group) was fed a diet consisting of alfalfa silage and a mixture of alfalfa and whole-plant corn silage, while the experimental group (RS group) received a diet in which one-third of the corn silage was replaced with straw while keeping the other components unchanged. The experiment lasted for a total of 21 days, with a pre-feeding period of 14 days and a formal period of 7 days. The rumen fluid collected on day 21 was used for the rumen fermentation parameters and metagenomic analysis. The concentrations of acetic acid, propionic acid, butyric acid, and total volatile fatty acids (TVFA) in the rumen of RS group cows were significantly lower than those in the CS group (p < 0.01). The ratio of acetic acid to propionic acid was significantly higher in the RS group compared to the CS group (p < 0.01). Metagenomic sequencing revealed that at the genus level, compared to the CS group, the abundance of unclassified bacteria, Bacteroides, Alistipes, Butyrivibrio, Chlamydia, Fibrobacter, unclassified Ruminococcaceae, and unclassified Bacteroidetes in the rumen of RS group cows increased, while the abundance of Eubacterium decreased ([LDA > 3.6], p < 0.05). Compared to the CS group, the enzymatic activities of α-L-arabinofuranosidase (EC3.2.1.55), β-xylosidase (EC3.2.1.37), β-glucosidase (EC3.2.1.21), β-glucosylceramidase (EC3.2.1.45), xylanase (EC3.2.1.8), and arabinanase (EC3.2.1.99) in the rumen of RS group cows increased (p < 0.05). According to the correlation analysis, Alistipes, Bacteroides, and Butyrivibrio showed a significant negative correlation with propionic acid (p < 0.05) and a significant positive correlation with the acetic acid-to-propionic acid ratio (p < 0.05). They also showed a significant positive correlation with GH2, GH3, GH20, GH29, GH43, GH78, GH92, CE1, GT4, β-glucosidase (EC3.2.1.21), α-L-arabinofuranosidase (EC 3.2.1.55), β-xylosidase (EC 3.2.1.37), β-glucosylceramidase (EC 3.2.1.45), xylanase (EC 3.2.1.8), and arabinanase (EC 3.2.1.99) (p < 0.05). In summary, straw can not only alter the composition and structure of the rumen microbiota in cows but also affect the relative abundance of CAZymes at different levels within the rumen. Cows may, thus, potentially improve the degradation efficiency of straw diets by increasing the abundance of certain rumen microbiota and enzymes.

Introduction: Bacillus licheniformis (B. licheniformis) is a microorganism with a wide range of probiotic properties and applications. Isolation and identification of novel strains is a major aspect of microbial research. Besides, different carbon sources have varying effects on B. licheniformis in regulating the microenvironment, and these mechanisms need to be investigated further.Methods: In this study, we isolated and identified a new strain of B. licheniformis from bovine rumen fluid and named it B. licheniformis NXU98. The strain was treated with two distinct carbon sources—microcrystalline cellulose (MC) and cellobiose (CB). A combination of transcriptome and proteome analyses was used to investigate different carbon source effects.Results: The results showed that B. licheniformis NXU98 ABC transporter proteins, antibiotic synthesis, flagellar assembly, cellulase-related pathways, and proteins were significantly upregulated in the MC treatment compared to the CB treatment, and lactate metabolism was inhibited. In addition, we used MC as a distinct carbon source to enhance the antibacterial ability of B. licheniformis NXU98, to improve its disease resistance, and to regulate the rumen microenvironment.Discussion: Our research provides a potential new probiotic for feed research and a theoretical basis for investigating the mechanisms by which bacteria respond to different carbon sources.

Introduction: The Alxa region is a typical arid and semi-arid ecosystem in northwestern China, where Bactrian camels and Mongolian cattle coexist under natural grazing conditions but differ markedly in feeding behavior and environmental tolerance. These differences may be reflected in host-associated gut microbial communities. This study compared the fecal microbiota of the two species to clarify microbial features associated with adaptation to the local desert grassland environment. Methods: Fecal samples were collected from 12 healthy adult Bactrian camels and 12 healthy adult Mongolian cattle grazing on spring pasture in the Alxa region. Total microbial DNA was extracted from fecal samples, and the hypervariable region of the bacterial 16S rRNA gene was amplified and sequenced using the Illumina platform. Community composition, alpha and beta diversity, differential taxa and microbial co-occurrence networks were then analyzed. Results: The Shannon index was significantly higher in Bactrian camels than in Mongolian cattle ( P = 0.049), whereas the Simpson index showed an opppsite trend ( P = 0.013). PCoA and NMDS analyses further showed significant separation between the fecal microbial communities of the two host species ( P = 0.001). At the phylum level, Bacillota and Bacteroidota dominated fecal samples from both species. At the genus level, the dominant taxa in Bactrian camels included Rikenellaceae_RC9_gut_group, norank_f_UCG-010, Christensenellaceae_R-7_group, UCG-005, Treponema and Bacteroides , whereas Mongolian cattle were dominated mainly by UCG-005, Rikenellaceae_RC9_gut_group and norank_f_UCG-010 . Co-occurrence network analysis showed that the camel microbial network had higher edge number, graph density and average degree, but lower network diameter, clustering coefficient and modularity, than the cattle network. The core nodes were UCG-005, Rikenellaceae_RC9_gut_group and Succinivibrio in Bactrian camels, and Rikenellaceae_RC9_gut_group, Bacteroides RF16 group and Prevotella in Mongolian cattle. Discussion: These findings provide preliminary microbial evidence that Bactrian camels and Mongolian cattle maintain their survival by shaping distinct gut microbial community structures and functional interaction patterns.