Rumen Bacteria Research Articles

Nutrient content, phytochemical profile and anti-methanogen potential of Chaya (Cnidoscolus aconitifolius) leaf extracts

Abstract Chaya leaves (Cnidoscolus aconitifolius) contain many nutrients and phytochemicals expected to reduce ruminants’ methane emissions. This study aims to determine the nutritional quality, phytochemical content and potential inhibitory power of Chaya leaf extract against the growth of rumen fluid methanogen bacteria. The methods used to determine nutrient content were proximate and fibre analysis. The phytochemical content tested were total phenols, tannins and flavonoids. Anti-methanogen test through inhibitory power using liquid culture selective media for methanogens. The results showed that Chaya leaves are a source of fibre feed, which also contains high crude protein (23 - 29%). The highest total phenol and tannin content in ethanol extract of Chaya leaves is 8.62 mg/g and 31.34 ppm, respectively. In contrast, ethyl acetate extract’s highest total flavonoid content is 13.96 mg/g. The highest potential inhibitory power against methanogen bacteria was shown by ethanol extract (50 mg/mL), causing inhibition of 44.56%. This study concludes that Chaya leaves have the potential to be used as ruminant animal feed and as a suppressor of methanogen bacteria, and further tests are recommended for methane gas production in vitro.

Dietary 5-hydroxytryptophan improves sheep growth performance by enhancing ruminal functions, antioxidant capacity, and tryptophan metabolism: in vitro and in vivo studies.

Hydroxytryptophan (5-HTP) can regulate the synthesis of 5-Hydroxytryptamine (5-HT) and melatonin (MT). In a previous metabolome analysis, we found that 5-HTP is an effective ingredient in yeast culture for regulating rumen fermentation. However, research on the effect of this microbial product (5-HTP) as a functional feed additive in sheep production is still not well explained. Therefore, this study examined the effects of 5-HTP on sheep rumen function and growth performance using in vitro and in vivo models. A two-factor in vitro experiment involving different 5-HTP doses and fermentation times was conducted. Then, in the in vivo experiment, 10 sheep were divided into a control group which was fed a basal diet, and a 5-HTP group supplemented with 8 mg/kg 5-HTP for 60 days. The results showed that 5-HTP supplementation had a significant effect on in vitro DMD, pH, NH3-N, acetic acid, propionic acid, and TVFA concentrations. 5-HTP altered rumen bacteria composition and diversity indices including Chao1, Shannon, and Simpson. Moreover, the in vivo study on sheep confirmed that supplementing with 8 mg/kg of 5-HTP improved rumen fermentation efficiency and microbial composition. This led to enhanced sheep growth performance and increased involvement in the tryptophan metabolic pathway, suggesting potential benefits. Dietary 5-HTP (8 mg/kg DM) improves sheep growth performance by enhancing ruminal functions, antioxidant capacity, and tryptophan metabolism. This study can provide a foundation for the development of 5-HTP as a functional feed additive in ruminants' production.

Effect of Pomegranate Peel or Bread Yeast on Rumen Fermentations Characteristics in Awassi Lambs

This study was conducted to determine the effect of pomegranate peel powder and baking yeast (saccharomyces cerevisiae) on rumen PH, the concentration of volatile fatty acids, the total number of bacteria, and the concentration of ammonia (NH3-N) in the rumen fluid. were selected 20 male iraqiawassi lambs at 3-4 months old, and randomly divided into 4 equal groups. The first group (control) was fed on concentrated dite at a rate of 3% of body weight with green fodder and free grazing, while pomegranate peels were added to the concentrated fodder for the second group (pomegranate peel group) at a rate of 1% of concentration dite, and bread yeast was added to the fodder of the third group (saccharomyces cerevisiae group) at a dose of 4 g for each animal. The control group was added to its diet with 1% pomegranate peel powder and yeast (saccharomyces cerevisiae) at a dose of 4 g per kg of concentrated feed. The results of the study showed a significant increase (P<0.05) in the pH value in the third and fourth groups compared to the control group, and the total count of rumen bacteria was significantly increased (P<0.05) in the three treatment groups compared to the control group, the concentration of volatile fatty acids(VFA) also increased significantly (P<0.05) in the third and fourth groups compared with the control group, while the concentration of rumen ammonia (NH3-N) significantly (P<0.05 ) decreased in the three treated groups compared with the control group. Conclusion: We conclude that adding pomegranate peels and yeast has improved rumen fermentation in terms of increasing the concentration of volatile fatty acids, reducing the concentration of ammonia, and increasing beneficial microorganisms in the rumen fluid.

Relationship between gut microbiota and its metabolite dysregulation and postoperative cognitive dysfunction in elderly male C57BL/6J mice after laparotomy exploration

Objective: To explore the relationship between gut microbiota and its metabolite dysregulation and postoperative cognitive dysfunction in elderly male C57BL/6J mice after laparotomy exploration. Methods: A total of 48 specific pathogen-free (SPF) male C57BL/6J mice, aged 16-17 months, were divided into two groups by random number table method: control group (n=24) and operation group (n=24). Mice in the operation group were induced with 1.4% isoflurane for 15 minutes, followed by a 10 minutes exploratory laparotomy anesthetized with 1.4% isoflurane and 100% oxygen, and anesthesia continued for 2 hours after surgery. Mice in control group were put in 100% oxygen for 2 hours. Feces and venous blood samples of both groups were collected 48 hours after surgery. Changes in the abundance and diversity of intestinal bacteria in the feces were detected by 16S rDNA gene sequencing. Functional changes of fecal metabolic profiles were detected by liquid chromatography tandem mass spectrometry (LC/MS) metabolomics and differential metabolite functions were analyzed. The serum level of interleukin (IL)-6, IL-1β and tumor necrosis factor-α (TNF-α) were detected by Enzyme-linked immunosorbent assay (ELISA). The cognitive function of the mice was detected by Morris water maze test 3 days after operation. Results: The postoperative escape latency of mice in control group and operation group was (22.0±4.9) and (35.0±5.1) s, and the target quadrant residence time was (26.0±3.7) and (16.0±2.9) s, respectively. Compared with the control group, the postoperative escape latency of mice in the operation group was prolonged (P=0.035), and the residence time in the target quadrant was reduced (P=0.006). The difference of intestinal flora between the two groups was comparable. The expression levels of Escherichia coli, shigella and clostridium in the operation group were up-regulated, while the expression levels of rumen bacteria and butyricobacteria were down-regulated. Fecal metabolic profiles of mice in control group and operation group were obtained by LC/MS, and 14 and 21 different metabolites were screened in positive and negative ion modes, respectively. The different metabolites in positive ion mode were glutamic acid, 2-indoleic acid, kynuuric acid and glyceraldehyde. The negative ion pattern differential metabolites are methionine, aspartic acid, L-threonine, tyrosyl-threonine and 5-hydroxyindole-3-acetic acid. The identified differential metabolite pathways are mainly involved in amino acid, fatty acid and tryptophan metabolism and nucleotide synthesis. There were no significant differences in serum levels of IL-1β, IL-6 and TNF-α between the two groups (all P>0.05). Conclusion: The dysregulated changes of gut microbiota and its metabolites are correlated with the occurrence of postoperative cognitive dysfunction in elderly male C57BL/6J mice. Anesthesia and surgery alter the structure of mice intestinal bacteria on the level of abundance, and change the metabolic balance and feces metabolomic phenotype.

Associations between the rumen microbiota and carcass merit and meat quality in beef cattle

The rumen microbiota is important for energy and nutrient acquisition in cattle, and therefore its composition may also affect carcass merit and meat quality attributes. In this study, we examined the associations between archaeal and bacterial taxa in the rumen microbiota of beef cattle and 12 different attributes, including hot carcass weight (HCW), dressing percentage, ribeye area (REA), intramuscular fat content, marbling score, fat thickness, yield grade, moisture content, purge loss, and shear force. There were significant correlations between the relative abundance of certain archaeal and bacterial genera and these attributes. Notably, Selenomonas spp. were positively correlated with live weight and HCW, while also being negatively correlated with purge loss. Members of the Christensenellaceae R-7, Moryella, and Prevotella genera exhibited positive and significant correlations with various attributes, such as dressing percentage and intramuscular fat content. Ruminococcaceae UCG-001 was negatively correlated with live weight, HCW, and dressing percentage, while Acidaminococcus and Succinivibrionaceae UCG-001 were negatively correlated with intramuscular fat content, moisture content, and marbling score. Overall, our findings suggest that specific changes in the rumen microbiota could be a valuable tool to improve beef carcass merit and meat quality attributes. Additional research is required to better understand the relationship between the rumen microbiota and these attributes, with the potential to develop microbiome-targeted strategies for enhancing beef production.Key points• Certain rumen bacteria were associated with carcass merit and meat quality• Moryella was positively correlated with intramuscular fat in beef carcasses• Acidaminococcus spp. was negatively correlated with marbling and intramuscular fat

Relationships among bacterial cell size, diversity, and taxonomy in rumen.

The rumen microbial community plays a crucial role in the digestion and metabolic processes of ruminants. Although sequencing-based studies have helped reveal the diversity and functions of bacteria in the rumen, their physiological and biochemical characteristics, as well as their dynamic regulation along the digestion process in the rumen, remain poorly understood. Addressing these gaps requires pure culture studies to demystify the intricate mechanisms at play. Bacteria exhibit morphological differentiation associated with different species. Based on the difference in size or shape of microorganisms, size fractionation by filters with various pore sizes can be used to separate them. In this study, we used polyvinylidene difluoride filters with pore sizes of 300, 120, 80, 40, 20, 8, 6, 2.1, and 0.6 μm. Bacterial suspensions were successively passed through these filters for the analysis of microbial population distribution using 16S rRNA gene sequences. We found that bacteria from the different pore sizes were clustered into four branches (> 120 μm, 40-120 μm, 6-20 μm, 20-40 μm, and < 0.6 μm), indicating that size fractionation had effects on enriching specific groups but could not effectively separate dominant groups by cell size alone. The species of unclassified Flavobacterium, unclassified Chryseobacterium, unclassified Delftia, Methylotenera mobilis, unclassified Caulobacteraceae, unclassified Oligella, unclassified Sphingomonas, unclassified Stenotrophomonas, unclassified Shuttleworthia, unclassified Sutterella, unclassified Alphaproteobacteria, and unclassified SR1 can be efficiently enriched or separated by size fractionation. In this study, we investigated the diversity of sorted bacteria populations in the rumen for preliminary investigations of the relationship between the size and classification of rumen bacteria that have the potential to improve our ability to isolate and culture bacteria from the rumen in the future.

Effects of dietary energy levels on microorganisms and short-chain fatty acids of rumen and tight junction proteins in Honghe Yellow cattle.

This study was conducted to investigate the effects of dietary energy levels on microorganisms and short-chain fatty acids (SCFAs) of rumen and the expression of tight junction proteins in Honghe Yellow cattle. A total of fifteen male Honghe Yellow cattle were randomly divided into three treatments (five replicates per treatment), consisting of formulated energy concentrations of 5.90 MJ/kg (high-energy diet, group H), 5.60 MJ/kg (medium-energy diet, group M) and 5.30 MJ/kg (low-energy diet, group L). The results showed that compared with group H, the expression of Claudin-1 in rumen epithelium of groups M and L was increased, but the expression of ZO-1 was decreased (p < 0.05). Moreover, compared with group H, group M down-regulated the expression of Occludin and Claudin-1 in the brain (p < 0.05). For rumen bacteria, the dominant phyla included Bacteroidetes and Firmicutes, the abundance of Actinobacteriota in groups M and L was significantly increased compared with group H (p < 0.05). At the genus level, the relative abundance of Corynebacterium, Eubacterium_nodatum_group and Neisseraceae in groups M and L was significantly decreased compared with group H (p < 0.05). For rumen fungi, the dominant phyla included Basidiomycota, Ascomycota and Neocariastigomycota, the relative abundance of Ascomycetes was significantly higher than that of groups M and L compared with group H (p < 0.05). At the genus level, the relative abundance of Neocelimastigaceae and Myceliophthora in groups M and L was significantly reduced compared with group H (p < 0.05). Furthermore, the expression of Claudin-1 in rumen epithelium was significantly positively correlated with Actinobacteriota, Corynebacterium and Neisseriaceae. The expression of ZO-1 in the spinal cord was significantly positively correlated with Myceliophthora. The expression of Occludin in brain was positively correlated with valerate content (p < 0.05). In summary, dietary energy levels affected the rumen microbiota of Honghe Yellow cattle. The expression of Claudin-1 in rumen epithelium and the total SCFAs concentration were increased with decreasing dietary energy levels, but the expression of Claudin-1 in brain and ZO-1 in the spinal cord were reduced with decreasing dietary energy levels. Meanwhile, the rumen microbiota and SCFAs were significantly correlated with the expression of TJP.

Diurnal shifts of rumen fermentation and microbial profiles revealed circadian rhythms of rumen bacteria, methanogens, and protozoa under high-grain and high-forage diets

In this study, we investigated how the composition and population of rumen microbiota shifted in response to diurnal oscillations under 2 different diets (high grain vs high forage). Five multiparous Holstein dairy cows with similar body weight, days in milk, and parity were enrolled in this study. The cows were fed high-grain (HG) diet for 21 d and then shifted to high-forage (HF) diet in the next 21 d (7-d washout and 14-d experimental period). During the experimental period, dry matter intake (DMI) and rumination activity were recorded, and rumen fluid was collected 8 times post-feeding every 6 h during the last 2 d of each dietary feeding period. The rumen microbial (bacterial, archaeal, and protozoal) population and composition were assessed using quantitative PCR and amplicon sequencing respectively. The daily dynamic of measurements was assessed using cosinor model. The associations between microbial taxa and rumen fermentation profiles were assessed using linear mixed model, in which the cows were termed as random intercept effects. Daily rhythmicity was observed for DMI, rumination activity, and rumen fermentation profiles under both diets. Additionally, rumination time, rumen pH, and acetate/propionate ratio had a higher mesor (the average level of diurnal fluctuations) under HF diet than in HG diet. The amplitude (the distance between the peak and mesor) of DMI, rumen pH, ammonia nitrogen, and total volatile acid concentration were higher under HG diet than in HF diet. Although no significant diurnal oscillation was observed in rumen microbial population, the relative abundance of 14 bacterial genera, one protozoal genus, and 2 archaeal species had significant diurnal oscillations under both HF and HG diets. Among them, the bacterial genera Ruminococcus and Colidextribacter had time at peak of rhythm within 0 to12 h after feeding, which were also negatively associated with the rumen acetate/propionate ratio. The bacterial genus Rikenellaceae_RC9_gut_group had time at peak of rhythm within 12 to 24 h after feeding, which was also positively associated with the rumen acetate/propionate ratio. Our study illustrated the daily dynamic on the rumen microbiota population and composition under different diets, and also identified the feeding-responsive rumen microbiota, highlighting a more targeted approach is needed to manipulate rumen microbiota.

Assessing the impact of three feeding stages on rumen bacterial community and physiological characteristics of Japanese Black cattle

In Japan, Japanese Black cattle, known for their exceptional meat quality owing to their abundant intramuscular fat, undergo a unique three-stage feeding system with varying concentrate ratios. There is limited research on physiological and rumen microbial changes in Japanese Black cattle during these stages. Therefore, this study aimed to examine Japanese Black steers in these three stages: early (T1, 12–14 months), middle (T2, 15–22 months), and late (T3, 23–30 months). The rumen bacteria of 21 cattle per phase was analyzed using 16S rRNA gene sequencing. Rumen bacterial diversity was significantly higher in T1, with a distinct distribution, than in T2 and T3. Specific phyla and genera were exclusive to each stage, reflecting the shifts in feed composition. Certain genera dominated each stage: T1 had Flexilinea, Streptococcus, Butyrivibrio, Selenomonas, and Kandleria; T2 had Bifidobacterium, Shuttleworthia, and Sharpea; and T3 had Acetitomaculum, Mycoplasma, Atopobium, and Howardella. Correlation analysis revealed significant associations between certain microbial populations and physiological parameters. These findings indicate that changes in energy content and feed composition are associated with physiological and ruminal alterations. This study may guide strategies to improve rumen health and productivity in Japanese Black cattle by modifying diets to specific fattening stages.

Targeted and untargeted metabolomics reveals meat quality in grazing yak during different phenology periods on the Qinghai-Tibetan Plateau

Yak meat is more popular among consumers because of its high nutritional value, but little attention has been paid to its meat quality, which is affected by different phenology periods grass. We hypothesized that seasonal variations in grass composition influenced the ruminal bacteria community, and eventually affected the meat quality of yaks. This study aims to investigate the relationship of meat quality in grazing yak as well as the key rumen bacteria using targeted and untargeted metabolomics and 16S rRNA during different phenology periods. The main three altered metabolic pathways in grazing yak, including amino acids biosynthesis, glutathione metabolism, and fatty acids biosynthesis, were found in the grass period (GP) group compared to the regreen period (RP) and hay period (HP) groups. The GP group had higher concentrations of flavor amino acids (FAA), polyunsaturated fatty acids (PUFA), and a lower ratio of n-6/n-3 compared with the RP group. Correlation analysis results showed that Rikenellaceae_RC9_gut_group was positively correlated with fatty acids and lipid metabolites, which might be involved in lipid metabolism. Pediococcus had a positive correlation with biological peptides, which could be involved in the metabolism of bioactive compounds. In conclusion, grass in different phenology periods was associated with modified amino acids and fatty acids composition of yak meat as well as altered regulation of biological pathways, which was correlated with changes in rumen bacterial communities.

INFLUENCE OF FEEDING CORN IMPURITIES ON RUMEN BACTERIA AND FERMENTATION CHARACTERISTICS OF SHEEP

This study was aimed to determine the effect of replacing treated and untreated corn impurities with urea instead of wheat bran on rumen bacteria and fermentation of Awassi lambs. Five levels of treated and untreated corn impurities as 44:0%, 32:11%, 20:22%, 10:32% and 0:39% bran:impurities in a 2×5 factorial experiment/ Completely Randomized Design using forty lambs with an initial weight of 27.45 ± 2.16kg and 4-5 months old. Individual feeding was used for 70 days and rumen fluid was sampled at 0, 3, 6h after morning feeding. Results showed an increasing (p&lt;0.05) rumen pH at zero time especially corn impurities treated with urea and increasing (p&lt;0.05) rumen ammonia at zero time and 3h after feeding with highly significant (p&lt;0.01) increased at 6h, and superiority increased of volatile fatty acids (VFA's) for urea treated corn impurities (P&lt;0.05) at zero time and after 3h of feeding, similar results for rumen bacterial count at zero time, 3h and 6h after morning feeding for two dilutions × 107 and × 109 Cfu/ml for impurities treated with urea. In conclusion, it is possible to use corn impurities instead of wheat bran, preferably treated with urea for positive increase rumen fermentation and total bacterial count in sheep.

Rumen degradable protein levels on fatty acid profile of rumen bacteria and milk fat of dairy cows supplemented with calcium salts of fatty acids.

This study aimed to evaluate the effects of calcium salts of fatty acids (CSFA) from soybean oil in diets with different levels of rumen degradable protein (RDP) on bio-hydrogenation extent, and fatty acid (FA) profile intake, omasal digesta, rumen bacteria, and milk fat. Eight Holstein lactating cows were used in a replicated 4 × 4 Latin square design. Treatments were arranged in a 2 × 2 factorial design with two CSFA levels (0 or 33.2g/kg DM of CSFA) and two RDP levels (98.0 or 110 g/kg DM). There was RDP and CSFA interaction effect on the omasal flow of total FA and some specific FA. Only in -CSFA diets, the higher RDP level increased omasal flow of total FA. Dietary RDP levels did not affect the FA profile of bacteria and milk fat. Feeding CSFA reduced or tended to reduce the bacterial proportion of C15:0, C16:0, C16:1, C17:0, and C18:0 FA and decreased the concentrations of short- and medium-chain FA (<18C) and increased the concentrations of unsaturated and long-chain FA (≥18C) in milk fat. Feeding CSFA of soybean oil increases the intake and omasal flow of FA and augments unsaturated FA content in bacteria pellets and milk fat.

Effects of different pH on number and community structure of rumen bacteria

Effects of different pH on number and community structure of rumen bacteria

The Application of Cows Rumen for Electricity Generation Through The Implementation of A Ceramic-Based Microbial Fuel Cell System

The growth in population is not adequately matched by the corresponding increase in energy demand. The imperative for prioritizing the exploration of alternative energy sources that possess attributes of safety, affordability, and ample access to raw materials cannot be overstated. An energy source with significant potential is a microbial fuel cell (MFC)-based energy source. This study aims to investigate the utilization of cow rumen as a substrate and source of nutrition in the bioenergy system of microbial fuel cells (MFCs). The present study aims to investigate the impact of substrate concentration and bacterial incubation duration derived from bovine rumen bacteria on the attainment of optimal power density. The research employed a Dual Chamber Microbial Fuel Cell (MFC) device using a Proton Exchange Membrane (PEM) constructed from ceramic materials. Daily observations were conducted over a period of 30 days. The performance of MFC was assessed utilizing the polarization technique. The findings indicated that altering the proportion of bovine rumen bacterial substrates and the duration of bacterial incubation had an impact on the power density seen in the Microbial Fuel Cell (MFC) system. The optimal conditions were attained when the substrate concentration reached 3640 ppm and after 7 days, resulting in a maximum power density of 864 mW/m2.

Bacterial community and diversity in the rumen of 11 Mongolian cattle as revealed by 16S rRNA amplicon sequencing

Through microorganism in the rumen of ruminant, plant fiber can be converted to edible food such as meat and milk. Ruminants had a rich and complex microbial community within the rumen, and the bacteria comprised the dominant proportion of the ruminal microbes. High-throughput sequencing offered a viable solution for the study of rumen microbes. In this study, rumen fluid samples were taken from 11 cattle from Inner Mongolian, the DNA of 11 rumen fluid samples were extracted and bacterial amplicons of the V4 regions of 16S rRNA were subjected to Illumina sequencing. More than 90,000 raw reads and 60,000 effect Tags per sample were obtained. 28,122 operational taxonomic units (OTUs) were observed from 11 samples, in average 2557 ± 361 OTUs for each sample. Bacteroidetes (44.41 ± 7.31%), Firmicutes (29.07 ± 3.78%), and Proteobacteria (7.18 ± 5.63%) were the dominant phyla among the bacteria of rumen, accounting for 82%. At the genus level, the highest relative abundance was Prevotella. Their functions were predicted using the Kyoto Encyclopedia of Genes and Genomes (KEGG). The results showed that they included metabolism, genetic information processing, environmental information processing and cellular processes. It explored the bacterial community diversity and composition of the rumen of Mongolian cattle. On the whole, our research showed that there was a high diversity as well as rich bacterial flora function of rumen bacteria in Mongolian cattle. Meanwhile, these findings provided information for further studies on the relationship between the community, diversity, functions of rumen bacteria and the nutritional physiological functions of the host.

The Effects of Composite Alkali-Stored Spent Hypsizygus marmoreus Substrate on Carcass Quality, Rumen Fermentation, and Rumen Microbial Diversity in Goats.

The objective of this study was to investigate the effects of composite alkali-stored spent Hypsizygus marmoreus substrate (SHMS) on carcass quality, rumen fermentation, and rumen microbial diversity in goats. Twenty-four 6-month-old Chuanzhong black goats with similar body weights (20 ± 5 kg) were selected and randomly divided into four groups (n = 6 per group) and received four treatments: 0% (control group, CG); 20% (low-addition group, LG); 30% (moderate-addition group, MG); and 40% (high-addition group, HG) of SHMS-replaced silage corn and oat hay. The experiment lasted for 74 days (including a 14 d adaptation period and a 60 d treatment period). The results of this study showed that MG and HG significantly improved the marble score of goat meat (p < 0.05). The flesh color score significantly increased in each group (p < 0.05). The fat color scores significantly increased in LG and MG (p < 0.05). There were no significant effects on the pH value or shear force of the longissimus dorsi in each group (p > 0.05). The cooking loss in MG was higher than that in CG (p < 0.05). The histidine and tyrosine contents in each group of muscles significantly increased (p < 0.05), with no significant effect on fatty acids (p > 0.05). The rumen pH of MG significantly decreased (p < 0.05), while the total volatile fatty acids (TVFAs) and ammoniacal nitrogen (NH3-N) increased by 44.63% and 54.50%, respectively. The addition of the SHMS altered both the alpha and beta diversities of the rumen microbiota and significant differences in the composition and structure of the four microbial communities. The dominant bacterial phylum in each group were Firmicutes and Bacteroidetes, with Prevotella 1 as the dominant bacterial genus. Correlation analysis revealed that rumen bacteria are closely related to the animal carcass quality and rumen fermentation. In the PICRUSt prediction, 21 significantly different pathways were found, and the correlation network showed a positive correlation between the Prevotella 1 and 7 metabolic pathways, while the C5-branched dibasic acid metabolism was positively correlated with nine bacteria. In summary, feeding goats with an SHMS diet can improve the carcass quality, promote rumen fermentation, and alter the microbial structure. The research results can provide a scientific reference for the utilization of SHMS as feed in the goat industry.

Analysis of Rumen Degradation Characteristics, Attached Microbial Community, and Cellulase Activity Changes of Garlic Skin and Artemisia argyi Stalk.

The purpose of this study was to study the chemical composition, rumen degradation characteristics, surface attached microbial community and cellulase activity of garlic skin (GS) and Artemisia argyi stalk (AS), in order to explain their feeding value. Four 14-month-old healthy Min Dong male goats with permanent rumen fistula were selected as experimental animals. The rumen degradation characteristics of GS and AS were determined by using the nylon bag method, and the bacterial composition, cellulase activity and their relationship on the surface of the two groups were analyzed with high-throughput sequencing of 16S rRNA gene. The results showed that in GS and AS, the effective degradation rate (ED) values of dry matter (DM) were 42.53% and 37.12%, the ED values of crude protein (CP) were 37.19% and 43.38%, the ED values of neutral detergent fiber (NDF) were 36.83% and 36.23%, and the ED values of acid detergent fiber (ADF) were 33.81% and 34.77%. During rumen degradation, the richness and evenness of bacteria attached to the AS surface were higher. At the phylum level, Bacteroidetes and Firmicutes were always the main rumen bacteria in the two groups. At the genus level, fiber-degrading bacteria such as Prevotella, Treponema, and Ruminococcus showed higher levels in GS (p < 0.05). Compared with GS, the activity of β-glucosidase (BG enzyme), endo-β-1,4-glucanase (C1 enzyme), exo-β-1,4-glucanase (Cx enzyme) and neutral xylanase (NEX enzyme) attached to AS surface showed a higher trend. Correlation analysis showed that the relative abundance of Succinivibrio and Rikenellaceae_RC9_gut_group was positively correlated with the rumen degradability of nutrients in GS, and the relative abundance of Christensenellaceae R-7_group, Succinivibrio and Ruminococcus was positively correlated with the rumen degradability of nutrients in AS. The conclusion of this study shows that AS has more potential to become ruminant roughage than GS. In addition, this study also revealed the relationship between cellulase activity and bacteria, which provided new information for us to better analyze the effects of GS and AS on the rumen of ruminants and provided an important theoretical basis for the development and utilization of agricultural by-products.

Isolation and characterization of tannin-degrading bacteria from the rumen of wild Hokkaido sika deer (Cervus nippon yezoensis).

We isolated tannin-degrading bacteria from the rumen of wild Hokkaido sika deer and characterized their phylogeny and tannase activity in relation to sample sources. The condensed tannin level was higher in all deer rumen samples (n = 20) than in forage-fed cattle rumen samples (n = 6), whereas no hydrolyzable tannins were detected in any of the rumen samples. Rumen bacteria were enumerated on nonselective brain heart infusion (BHI) agar medium and then transferred onto tannic acid-containing BHI agar plates to screen for bacteria only showing growth (tannin-resistant bacteria) and those showing both growth and a clear zone (tannin-degrading bacteria). Summer samples provided only tannin-resistant bacteria, none of which showed tannin-degrading activity. Although winter samples also provided tannin-resistant bacteria, most isolates exhibited tannin-degrading activity. A total of 70 isolates exhibiting tannin-degrading activity were classified as Streptococcus bovis group based on 16S rRNA gene sequencing and further classified into two groups, either group A or group B. Group A consisted of isolates showing weak tannase activity, whereas group B included a majority of the isolates exhibiting high tannase activity. These results suggest that wild Hokkaido sika deer develop tannin-degrading Streptococcus in the rumen during winter, which allows access to woody food materials rich in tannins.

Potential of Bacteria from Goat Rumen as Growth Promoters, Nitrogen Fixation, Phosphate Solubilizers, and Biological Controllers

Modern agriculture faces the challenge of global climate change; therefore, plants cannot adapt to dynamic environmental conditions. Of course, alternatives are needed that utilize the potential of microbes from goat rumen. The research aims to obtain microbes from the goat rumen that have dual abilities as plant growth promoters (PGP), nitrogen fixation, phosphate soluble, and biological control agents. A total of 15 isolates were tested for their ability to act as growth promoters and biocontrol agents. Research on testing bacterial isolates as PGP was conducted using a completely randomized design with two replications. Bacteria from goat rumen can stimulate growth by producing the IAA hormone (29.00–207.67 ppm), fix nitrogen, dissolve phosphate (9 isolates), increase the root length of soybean seedlings, and be biocontrol agents in producing cellulase and protease enzymes (13 isolates) and amylase enzymes. These goat rumen bacteria are different from those in previous research that focused only on the use of goat rumen as a liquid fertilizer and its role as a biodecomposer. This research has an impact on increasing plant growth, the cycle of nutrients, especially the N and P elements, and biological control agents, thus supporting sustainable agriculture.

Isolation and characterization of strictly anaerobic cellulolytic rumen bacterial species from Sahiwal cattle.

To isolate and characterize cellulolytic rumen bacteria from the rumen of Sahiwal cattle using rumen bacterial inoculum to increase the nutritional value of rice bran used as broiler feed. The ruminal liquid was kept at an optimal pH of 6.9 and a redox potential of less than -300 mV while being incubated anaerobically at 39°C in a medium containing rumen fluid glucose cellobiose agar. By using the Hungate technique, the organisms were detected based on their morphological, physiological, biochemical, and molecular testing. The findings revealed that the isolated Ruminococcus albus, and Ruminococcus flavifaciens were obligate anaerobic, generally Gram-positive, nonmotile cocci or rod, single or pair, occasionally short chain, producing yellow pigment when grown on cellulose, and having a clear zone around the colonies. Both isolate fermented sugars such as cellobiose, glucose, and lactose, as well as decomposed xylan. The results also showed that the isolates recognized as Ruminococcus spp., a cellulolytic rumen bacterium, were catalase-negative, indole-negative, and gelatin liquefaction-positive. Isolation and characterization of Ruminococcus spp. may be helpful for Bangladesh in reducing the cost of producing poultry feed and circumventing restrictions on rice bran use. We can also develop more efficient and long-lasting plans to enhance poultry performance and feed efficiency, as well as increase the nutritional value of rice bran used as broiler feed, by understanding how various Ruminococcus spp. function in this process.