Effects of yak rumen anaerobic fungus Orpinomyces sp. YF3 fermented on in vitro wheat straw fermentation and microbial communities in dairy goat rumen fluid, with and without fungal flora.

Rumen fungi play an essential role in the breakdown of dietary fibrous components, facilitating the provision of nutrients and energy to the host animals. This study investigated the fermentation characteristics and effects on rumen microbiota of yak rumen anaerobic fungus Orpinomyces sp. YF3 in goat rumen fluid, both with and without fungal flora, utilizing anaerobic fermentation bottles. Crushed and air-dried wheat straw served as the fermentation substrate, and cycloheximide was used to eradicate microorganisms from the rumen fluid of dairy goats. The experiment compromised four treatment groups (2×2 factorial design): control (C); yak fungus group (CF, Orpinomyces sp. YF3); goat fungi eliminated group (CA, antibiotic: 0.25 mg/mL cycloheximide); goat fungi eliminated+yak fungus group (CAF). Each treatment had six replicates. Fermentation characteristics and microbial composition of the fermentation media were analyzed using one-way analysis of variance and high-throughput sequencing technology. The findings revealed that in the Orpinomyces sp. YF3 addition group (CF and CAF groups), there were significant increases in ammonia nitrogen concentration by 70%, total volatile fatty acids (VFA) by 53%, as well as acetate, isobutyrate, and valerate concentrations, and the ratio of acetate to propionate (p < 0.05), while the propionate proportion declined by 13%, alongside a reduction of butyrate concentration (p < 0.05). Similarly, in the CF and CAF groups, there were a notable increase in the relative abundance of Bacteroidota, Synergistota, Desulfobacterota, Actinobacteria, and Fusobacteriota, alongside a decrease in the relative abundance of Fibrobacterota and Proteobacteria (p < 0.05). Bacteria exhibiting increased relative abundance were positively correlated with the activity of carboxymethyl cellulase and avicelase, total VFA concentration, and acetate proportion, while showing a negatively correlation with propionate proportion. In conclusion, supplementing rumen fermentation media with yak rumen anaerobic fungus Orpinomyces sp. YF3 led to an increase in bacteria associated with fibre degradation and acetic acid production, a decrease in propionate-producing bacteria, enhanced the activity of plant cell wall degrading enzymes, and promoted cellulose degradation, ultimately elevating total VAF concentration and acetate proportion. This presents a novel approach to enhance roughage utilization in ruminants.

Hydroxy-selenomethionine supplementation promotes the in vitro rumen fermentation of dairy cows by altering the relative abundance of rumen microorganisms.

AIMS: This study aims to investigate the effect of hydroxy-selenomethionine supplementation on the in vitro rumen fermentation characteristics and microorganisms of Holstein cows. METHODS AND RESULTS: Five fermentation substrates, including control (without selenium supplementation, CON), sodium selenite supplementation (0.3 mg kg-1 DM, SS03), and hydroxy-selenomethionine supplementation (0.3, 0.6 and 0.9 mg kg-1 DM, SM03, SM06 and SM09, respectively) were incubated with rumen fluid in vitro. The results showed that in vitro dry matter disappearance and gas production at 48 h was significantly higher in SM06 than SM03, SS03 and CON; propionate and total volatile fatty acid (VFA) production was higher in SM06 than CON. Moreover, higher species richness of rumen fluid was found in SM06 than others. Higher relative abundance of Prevotella and Prevotellaceae-UCG-003 and lower relative abundance of Ruminococcus-1 were detected in SM06 than CON. Besides, higher relative abundance of Ruminococcaceae_UCG-005 was found in CON than other treatments. CONCLUSIONS: It is observed that 0.6 mg kg-1 DM hydroxy-selenomethionine supplementation could increase cumulative gas production, propionate, and total VFAs production by altering the relative abundance of Prevotella, Prevotellaceae-UCG-003, Ruminococcaceae_UCG-005 and Ruminococcus-1, so that it can be used as a rumen fermentation regulator in Holstein cows. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides an optimal addition ratio of hydroxy-selenomethionine on rumen fermentation and bacterial composition via an in vitro test.

Invited review: Plant polyphenols and rumen microbiota responsible for fatty acid biohydrogenation, fiber digestion, and methane emission: Experimental evidence and methodological approaches.

The interest of the scientific community in the effects of plant polyphenols on animal nutrition is increasing. These compounds, in fact, are ubiquitous in the plant kingdom, especially in some spontaneous plants exploited as feeding resources alternative to cultivated crops and in several agro-industry by-products. Polyphenols interact with rumen microbiota, affecting carbohydrate fermentation, protein degradation, and lipid metabolism. Some of these aspects have been largely reviewed, especially for tannins; however, less information is available about the direct effect of polyphenols on the composition of rumen microbiota. In the present paper, we review the most recent literature about the effect of plant polyphenols on rumen microbiota responsible for unsaturated fatty acid biohydrogenation, fiber digestion, and methane production, taking into consideration the advances in microbiota analysis achieved in the last 10 yr. Key aspects, such as sample collection, sample storage, DNA extraction, and the main phylogenetic markers used in the reconstruction of microbial community structure, are examined. Furthermore, a summary of the new high-throughput methods based on next generation sequencing is reviewed. Several effects can be associated with dietary polyphenols. Polyphenols are able to depress or modulate the biohydrogenation of unsaturated fatty acids by a perturbation of ruminal microbiota composition. In particular, condensed tannins have an inhibitory effect on biohydrogenation, whereas hydrolyzable tannins seem to have a modulatory effect on biohydrogenation. With regard to fiber digestion, data from literature are quite consistent about a general depressive effect of polyphenols on gram-positive fibrolytic bacteria and ciliate protozoa, resulting in a reduction of volatile fatty acid production (mostly acetate molar production). Methane production is also usually reduced when tannins are included in the diet of ruminants, probably as a consequence of the inhibition of fiber digestion. However, some evidence suggests that hydrolyzable tannins may reduce methane emission by directly interacting with rumen microbiota without affecting fiber digestion.

Relationship between the structure and composition of rumen microorganisms and the digestibility of neutral detergent fibre in goats.

OBJECTIVE: This experiment was conducted to compare the structure and composition of ruminal microorganisms in goats with high and low neutral detergent fibre (NDF) digestibility. METHODS: Nineteen crossbred goats were used as experimental animals and fed the same total mixed rations during the 30-day pre-treatment and 6-day digestion trialperiods. All faeces were collected during the digestion period for measuring the NDF digestibility. Then, high and the low NDF digestibility individuals were chosen for the high NDF digestibility group (HFD) and low NDF digestibility group (LFD), respectively. Rumen contents were collected for total microbial DNA extraction. The V4 region of the bacterial 16S rRNA gene was amplified using universal primers of bacteria and sequenced using high-throughput sequencer. The sequences were mainly analysed by QIIME 1.8.0. RESULTS: A total of 18,694 operational taxonomic units were obtained, within 81.98% belonged to bacteria, 6.64% belonged to archaea and 11.38% was unassigned microorganisms. Bacteroidetes, Firmicutes, and Proteobacteria were the predominant microbial phyla in both groups. At the genus level, the relative abundance of fifteen microorganisms were significantly higher (p<0.05) and six microorganisms were extremely significantly higher (p<0.01) in LFD than HFD. Overall, 176 core shared genera were identified in the two groups. The relative abundance of 2 phyla, 5 classes, 10 orders, 13 families and 15 genera had a negative correlation with NDF digestibility, but only the relative abundance of Pyramidobacter had a positive correlation with NDF digestibility. CONCLUSION: There were substantial differences in NDF digestibility among the individual goats, and the NDF digestibility had significant correlation with the relative abundance of some ruminal microorganisms.

Intensive feeding alters the rumen microbiota and its fermentation parameters in natural grazing yaks.

Introduction: Amidst the challenging environmental conditions characterized by low oxygen levels and cold temperatures on the plateau, alterations in nutrient supply emerge as pivotal factors influencing the survival and reproduction of yaks. Intensive feeding stands out as a substantial mechanism for nutrient provision, initiating discernible changes in the host's rumen flora. Within the extreme natural conditions prevailing in the plateau area of northwest Yunnan, China, there exists a con-strained comprehension of the variations in rumen microflora, fermentation parameters, and growth responses exhibited by yaks subjected to intensive feeding. Methods: This study employs 16S rRNA and ITS sequencing methods to scrutinize the rumen flora of yaks engaged in both natural grazing (G) and intensive feeding (F) on the plateau. Results: The outcomes unveil that, during the severe winter season, yaks adeptly modulate the abundance and diversity of rumen flora in response to dietary modifications under intensive feeding, aiming to optimize the efficient utilization of dietary fiber and energy. Principal Coordinate Analysis (PCoA) illustrates a substantial alteration in the rumen microbial community of naturally grazing yaks when exposed to intensive feeding. The natural grazing group manifests a higher prevalence of Firmicutes and Bacteroidetes, while the intensive feeding group exhibits heightened levels of Prevotella in the rumen. The Rikenellaceae _ RC9 _ gut_ group, associated with mycobacteria, prevails more abundantly in the natural grazing setting. PICRUSt2 analysis indicates that intensive feeding induces bacterial gene overexpression linked to protein metabolism. Rumen fungi showcase heightened diversity under intensification. Intensive feeding results in an augmented abundance of non-fiber-degrading bacteria and semi-fiber-degrading bacteria, accompanied by elevated concentrations of Volatile Fatty Acids (VFA). Discussion: These findings yield novel insights into the shifts in the rumen microflora of yaks acclimated to intensive feeding in high-altitude environments, provide an important reference for the nutritional regulation of supplemental feeding of natural grazing yaks in the cold season, ultimately contributing to their enhanced growth.

Supplementation of Alternanthera sissoo pellets on feed digestion, rumen fermentation, and protozoal population in Thai native beef cattle.

The objective of this experiment was to study the effects of Brazilian spinach (Alternanthera sissoo) pellet (BSP) supplementation on rumen fermentation, protozoal population, and methane (CH4) estimation in beef cattle. Four male Thai native beef cattle, 3 years old, with an average bodyweight of 180 ± 5 kg, were randomly arranged in a 4 × 4 Latin square design. The cattle were supplemented (on-top) with four levels of BSP (2, 4, 6, and 8% dry matter intake (DMI), respectively). The roughage component, derived from rice straw, was fed at 40 % of DMI, while the concentrate diet was fed at 60 % of DMI. The result of the experiment demonstrated that BSP supplementation had no effect on the DMI, nutrient intake, or nutrient digestibility (p > 0.05). Rumen pH and ammonia-nitrogen concentration were not significant, while the average protozoal population linearly decreased (p = 0.002) with BSP supplementation. Mean blood urea-nitrogen concentration was linearly increased (p = 0.004) when increasing the level of BSP. Brazilian spinach pellet had no significant effect on total volatile fatty acids (TVFA), VFA profiles, and CH4 estimation (p > 0.05). Nitrogen balance was no different from the supplementation of BSP. The study indicates that Brazilian spinach pellet supplementation showed no noticeable effects on feed intake, rumen parameters, and nitrogen utilization; however, at 6-8% of DMI, there was a decrease in protozoal population, with no corresponding reduction in CH4 estimation.

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.

Effect of plants containing secondary compounds with palm oil on feed intake, digestibility, microbial protein synthesis and microbial population in dairy cows.

The objective of this study was to determine the effect of rain tree pod meal with palm oil supplementation on feed intake, digestibility, microbial protein synthesis and microbial populations in dairy cows. Four, multiparous early-lactation Holstein-Friesian crossbred (75%) lactating dairy cows with an initial body weight (BW) of 405±40 kg and 36±8 DIM were randomly assigned to receive dietary treatments according to a 4×4 Latin square design. The four dietary treatments were un-supplementation (control), supplementation with rain tree pod meal (RPM) at 60 g/kg, supplementation with palm oil (PO) at 20 g/kg, and supplementation with RPM at 60 g/kg and PO at 20 g/kg (RPO), of total dry matter intake. The cows were offered concentrates, at a ratio of concentrate to milk production of 1:2, and chopped 30 g/kg of urea treated rice straw was fed ad libitum. The RPM contained condensed tannins and crude saponins at 88 and 141 g/kg of DM, respectively. It was found that supplementation with RPM and/or PO to dairy cows diets did not show negative effects on feed intake and ruminal pH and BUN at any times of sampling (p>0.05). However, RPM supplementation resulted in lower crude protein digestibility, NH3-N concentration and number of proteolytic bacteria. It resulted in greater allantoin absorption and microbial crude protein (p<0.05). In addition, dairy cows showed a higher efficiency of microbial N supply (EMNS) in both RPM and RPO treatments. Moreover, NDF digestibility and cellulolytic bacteria numbers were highest in RPO supplementation (p<0.05) while, supplementation with RPM and/or PO decreased the protozoa population in dairy cows. Based on this study, supplementation with RPM and/or PO in diets could improve fiber digestibility, microbial protein synthesis in terms of quantity and efficiency and microbial populations in dairy cows.

High-Dose Vitamin E Supplementation Can Alleviate the Negative Effect of Subacute Ruminal Acidosis in Dairy Cows.

The aim of this trial was to assess whether the supplementation of vitamin E (VE) in high-concentrate diets could improve the fermentation and blood metabolism in the rumen of dairy cows, thereby modulating the degree of the subacute ruminal acidosis (SARA) response and improving the performance. Seven Holstein cows (four fitted with ruminal cannulas) were fed three diets (total mixed rations) during three successive periods (each lasted for 18 d): (1) the control diet (CON); (2) a high-grain (HG) diet, which was the control diet supplied with a 15% finely ground wheat diet (FGW); and (3) a high-VE diet (HGE), which was the control diet provided with a 15% FGW and 12,000 IU of VE/head per day. The results indicated that VE was able to alleviate the reduction in the dry matter intake (DMI) and milk fat yield in cows caused by HG diets. The supplementation of VE significantly reduced the levels of lipopolysaccharide (LPS), histamine (HIS), and the total volatile fatty acid (TVFA) in the rumen. The supplementation of VE observably increased the antioxidant capacity of the milk and plasma. In addition, VE markedly reduced the plasma levels of endotoxin, HIS, and pro-inflammatory factors. The supplementation of VE significantly enriched the differential metabolites of the purine metabolism, cysteine, methionine metabolism, and ABC transporter synthesis pathway in the serum. The supplementation of VE also significantly increased the relative abundance of Succiniclasticum and decreased the relative abundance of Treponema, thus reducing the production of TVFA in the rumen. In conclusion, considering that the cows in this trial had high ketone levels (BHBA > 2.3 mmol/L), we found that VE could improve the rumen fermentation and blood metabolism by modulating the relative abundance of rumen microorganisms, thereby mitigating a range of adverse effects caused by SARA.

Responses of rumen microorganisms and metabolites to different roughage of domesticated Tibetan sheep.

Tibetan sheep can utilize high fiber feeds well. However, the mechanisms of rumen microbiota and metabolites in response to different roughage in a housed environment are still unclear. We fed Tibetan sheep with three different roughage diets: 50% whole corn silage (TS), 50% wheatgrass group (TW), and 25% each of whole corn silage and wheatgrass (TM). Subsequently, meat traits, rumen contents 16S rRNA and metabolomics were studied. The results showed that feeding wheat straw to Tibetan sheep significantly increased the abundance of bacteria such as Ruminococcus and Succiniclasticum in the rumen. These microorganisms significantly increased metabolites such as beta-alanyl-L-lysine, butanoic acid and prostaglandin E2. Eventually, production performance, such as carcass weight and intramuscular fat and meat quality characteristics, such as color and tenderness were improved by altering the rumen's amino acid, lipid and carbohydrate metabolism. This study demonstrated that including 25% wheatgrass and 25% whole corn silage in the diet improved the performance of Tibetan sheep, revealing the effect of the diet on the performance of Tibetan sheep through rumen microorganisms and metabolites.

Effects of Sodium Nitrate and Coated Methionine on Lactation Performance, Rumen Fermentation Characteristics, Amino Acid Metabolism, and Microbial Communities in Lactating Buffaloes.

Sodium nitrate is used as a non-protein nitrogen supplement while methionine is considered as a common methionine additive for ruminants. This study investigated the effects of sodium nitrate and coated methionine supplementation on milk yield, milk composition, rumen fermentation parameters, amino acid composition, and rumen microbial communities in lactating buffaloes. Forty mid-lactation multiparous Murrah buffaloes within the initial days in milk (DIM) = 180.83 ± 56.78 d, milk yield = 7.63 ± 0.19 kg, body weight = 645 ± 25 kg were selected and randomly allocated into four groups (N = 10). All of animals received the same total mixed ratio (TMR) diet. Furthermore, the groups were divided into the control group (CON), 70 g/d sodium nitrate group (SN), 15 g/d palmitate coated L-methionine group (MET), and 70 g/d sodium nitrate +15 g/d palmitate coated L-methionine group (SN+MET). The experiment lasted for six weeks, including two weeks of adaption. The results showed that most rumen-free amino acids, total essential amino acids, and total amino acids in Group SN increased (p < 0.05), while the dry matter intake (DMI) and rumen acetate, propionate, valerate, and total volatile fatty acids (TVFA) in Group MET decreased (p < 0.05). However, there was no significant difference in milk yield, milk protein, milk fat, lactose, total solid content, and sodium nitrate residue in milk among groups (p > 0.05). Group SN+MET had a decreased rumen propionate and valerate (p < 0.05), while increasing the Ace, Chao, and Simpson indices of alpha diversity of rumen bacteria. Proteobacteria and Actinobacteriota were significantly increased (p < 0.05) in Group SN+MET, but Bacteroidota, and Spirochaetota were decreased (p < 0.05). In addition, Group SN+MET also increased the relative abundance of Acinetobacter, Lactococcus, Microbacterium, Chryseobacterium, and Klebsiella, which were positively correlated with cysteine and negatively correlated with rumen acetate, propionate, valerate, and TVFA. Rikenellaceae_RC9_gut_group was identified as a biomarker in Group SN. Norank_f__UCG-011 was identified as a biomarker in Group MET. Acinetobacter, Kurthia, Bacillus, and Corynebacterium were identified as biomarkers in Group SN+MET. In conclusion, sodium nitrate increased rumen free amino acids, while methionine decreased dry matter intake (DMI) and rumen volatile fatty acids. The combined use of sodium nitrate and methionine enriched the species abundance of microorganisms in the rumen and affected the composition of microorganisms in the rumen. However, sodium nitrate, methionine, and their combination had no significant effect on the milk yield and milk composition. It was suggested that the combined use of sodium nitrate and methionine in buffalo production was more beneficial.

Effect of Sodium Nitrate and Cysteamine on In Vitro Ruminal Fermentation, Amino Acid Metabolism and Microbiota in Buffalo.

Nitrate is used as a methane inhibitor while cysteamine is considered as a growth promoter in ruminants. The present study evaluated the effect of sodium nitrate and cysteamine on methane (CH4) production, rumen fermentation, amino acid (AA) metabolism, and rumen microbiota in a low protein diet. Four treatments containing a 0.5 g of substrate were supplemented with 1 mg/mL sodium nitrate (SN), 100 ppm cysteamine hydrochloride (CS), and a combination of SN 1 mg/mL and CS 100 ppm (CS+SN), and a control (no additive) were applied in a completely randomized design. Each treatment group had five replicates. Two experimental runs using in vitro batch culture technique were performed for two consecutive weeks. Total gas and CH4 production were measured in each fermentation bottle at 3, 6, 9, 12, 24, 48, and 72 h of incubation. The results showed that SN and CS+SN reduced the production of total gas and CH4, increased the rumen pH, acetate, acetate to propionate ratio (A/P), and microbial protein (MCP) contents (p < 0.05), but decreased other volatile fatty acids (VFA) and total VFA (p = 0.001). The CS had no effect on CH4 production and rumen fermentation parameters except for increasing A/P. The CSN increased the populations of total bacteria, fungi, and methanogens but decreased the diversity and richness of rumen microorganisms. In conclusion, CS+SN exhibited a positive effect on rumen fermentation by increasing the number of fiber degrading and hydrogen-utilizing bacteria, with a desirable impact on rumen fermentation while reducing total gas and CH4 production.

Metagenomic Analysis Revealed Differences in Composition and Function Between Liquid-Associated and Solid-Associated Microorganisms of Sheep Rumen.

The rumen microbiota plays a key role in the utilization of plant materials by ruminants, yet little is known about the key taxa and their genetic functions of the rumen sub-environment involved in the ruminal degradation process. Understanding the differences in the composition and function of ruminal microbiota in the liquid-associated (LA) and solid-associated (SA) systems is needed to further study and regulate rumen function and health. In this study, rumen contents of nine sheep were collected to separate LA and SA systems with elution and centrifugal precipitation. Metagenome sequencing was used to investigate the differences in microbial composition and genetic functions of LA and SA systems, with special emphasis on their degradational potential toward carbohydrates. Results showed that the dominant species composition was similar between the two systems, but SA microorganisms had a higher relative abundance than LA microorganisms in all taxa. The concentration of fiber-degrading bacteria, such as Ruminococcus, Treponema, and Fibrobacter, was higher and Prevotella was lower in the SA vs. LA system. Additionally, SA microorganisms dominated in cellulose degradation, while LA microorganisms were more important in starch utilization based on the Kyoto Encyclopedia of Genes and Genomes (KEGG) Orthology (KO)'s functional categories and Carbohydrate-Active Enzymes (CAZymes). In general, SA microorganisms are more abundant and important in metabolic functions than LA, such as carbohydrate and amino acid metabolisms. In summary, the key differential biomarkers between LA and SA systems were Prevotella, Ruminococcus, Treponema, and Fibrobacter. Ruminal microbes degraded carbohydrates synergistically with SA, thus, more focusing on cellulose and hemicellulose, while LA is more important to starch.

Dietary Cysteamine Supplementation Remarkably Increased Feed Efficiency and Shifted Rumen Fermentation toward Glucogenic Propionate Production via Enrichment of Prevotella in Feedlot Lambs.

Cysteamine (CS) is an essential nutritional regulator that improves the productive performance of animals by regulating somatotropic hormone secretion. To investigate the fattening potential and effects of CS on rumen microbial fermentation, 48 feedlot lambs were randomly assigned to four groups and fed diets supplemented with different CS concentrations (0, 20, 40, and 60 mg/kg BW). An increase in dietary CS concentrations linearly increased the average daily gain (ADG) and dry matter intake (p < 0.05) but decreased the feed-to-gain ratio (p < 0.01). For the serum hormone, increasing the dietary CS concentration linearly decreased somatostatin and leptin concentration (p < 0.01) but linearly increased the concentration of growth hormone and insulin-like growth factor 1 (p < 0.01). Regarding rumen fermentation, ruminal pH, ammonia-N, and butyrate content did not differ among the four treatments, although dietary CS supplementation linearly increased microbial protein and propionate and decreased the amount of acetate (p < 0.05). Furthermore, an increase in dietary CS concentrations quadratically decreased the estimated methane production and methane production per kg ADG (p < 0.05). High-throughput sequencing revealed that increased dietary CS concentrations quadratically increased Prevotella (p < 0.05), and Prevotella and norank_f__norank_o__Clostridia_UCG-014 were positively correlated with growth performance and rumen fermentation in a Spearman correlation analysis (r > 0.55, p < 0.05). Overall, a CS concentration higher than 20 mg/kg BW produced growth-promoting effects by inhibiting somatostatin concentrations and shifting the rumen toward glucogenic propionate fermentation by enriching Prevotella. In addition, Prevotella and norank_f__norank_o__Clostridia_UCG-014 were positively correlated with growth performance in lambs.

Ruminal pH pattern, fermentation characteristics and related bacteria in response to dietary live yeast (Saccharomyces cerevisiae) supplementation in beef cattle.

OBJECTIVE: In this study we aimed to evaluate the effect of dietary live yeast supplementation on ruminal pH pattern, fermentation characteristics and associated bacteria in beef cattle. METHODS: This work comprised of in vitro and in vivo experiments. In vitro fermentation was conducted by incubating 0%, 0.05%, 0.075%, 0.1%, 0.125%, and 0.15% active dried yeast (Saccharomyces cerevisiae, ADY) with total mixed ration substrate to determine its dose effect. According to in vitro results, 0.1% ADY inclusion level was assigned in in vivo study for continuously monitoring ruminal fermentation characteristics and microbes. Six ruminally cannulated steers were randomly assigned to 2 treatments (Control and ADY supplementation) as two-period crossover design (30-day). Blood samples were harvested before-feeding and rumen fluid was sampled at 0, 3, 6, 9, and 12 h post-feeding on 30 d. RESULTS: After 24 h in vitro fermentation, pH and gas production were increased at 0.1% ADY where ammonia nitrogen and microbial crude protein also displayed lowest and peak values, respectively. Acetate, butyrate and total volatile fatty acids concentrations heightened with increasing ADY doses and plateaued at high levels, while acetate to propionate ratio was decreased accordingly. In in vivo study, ruminal pH was increased with ADY supplementation that also elevated acetate and propionate. Conversely, ADY reduced lactate level by dampening Streptococcus bovis and inducing greater Selenomonas ruminantium and Megasphaera elsdenii populations involved in lactate utilization. The serum urea nitrogen decreased, whereas glucose, albumin and total protein concentrations were increased with ADY supplementation. CONCLUSION: The results demonstrated dietary ADY improved ruminal fermentation dosedependently. The ruminal lactate reduction through modification of lactate metabolic bacteria could be an important reason for rumen pH stabilization induced by ADY. ADY supplementation offered a complementary probiotics strategy in improving gluconeogenesis and nitrogen metabolism of beef cattle, potentially resulted from optimized rumen pH and fermentation.

Effect of Oregano Oil and Cobalt Lactate on Sheep In Vitro Digestibility, Fermentation Characteristics and Rumen Microbial Community.

The objective of this experiment was to evaluate the effect of different EOC (0.1425% cobalt lactate + 1.13% oregano essential oil + 98.7275% carrier) levels on in vitro rumen fermentation and microbial changes. Six EOC levels (treatments: 0 mg·L-1, CON; 50 mg·L-1, EOC1; 100 mg·L-1, EOC2; 400 mg·L-1, EOC3; 800 mg·L-1, EOC4 and 1500 mg·L-1, EOC5) were selected to be used to in vitro incubation. The in vitro dry matter digestibility (IVDMD), in vitro neutral detergent fiber digestibility (IVNDFD), in vitro acid detergent fiber digestibility (IVNDFD), pH, ammonia-nitrogen (NH3-N) concentration, total volatile fatty acid (TVFA) concentration and microbial protein (MCP) concentration were measured after 48 h incubation, after which the groups with significant nutrient digestibility and fermentation parameters were subjected to 16S rRNA sequencing. The results showed that the total gas production (GP) of the EOC5 group was higher than that of the other groups after 12 h of in vitro incubation. TVFA, NH3-N and MCP concentrations were also shown to be higher in group EOC5 than those in other groups (p < 0.05), while NH3-N and MCP concentrations in the EOC2 group were lower than those in other groups significantly (p < 0.05). The molar ratio of acetic acid decreased while the molar ratio of propionic acid increased after the addition of EOC. 16S rRNA sequencing revealed that the rumen microbiota was altered in response to adding EOC, especially for the EOC5 treatment, with firmicutes shown to be the most abundant (43.1%). The relative abundance of Rikenellaceae_RC9_gut_group was significantly lower, while the relative abundance of uncultured_bacterium_f_Muribaculaceae and Succiniclasticum was significantly higher in the EOC5 group than those in other groups (p < 0.05). Comprehensive analysis showed that EOC (1500 mg·L-1) could significantly increase gas production, alter sheep rumen fermentation parameters and microbiota composition.

Relationship between rumen microbial differences and traits among Hu sheep, Tan sheep, and Dorper sheep.

Rumen microbes play an important role in the growth and development of ruminants. Differences in variety will affect the rumen community structure. The three excellent sheep breeds were selected for this study (Hu sheep, Tan sheep, and Dorper sheep) have different uses and origins. The sheep were raised on the same diet to 180 d of age in a consistent environment. 16S rDNA V3 to V4 region sequencing was used to assess the rumen microbes of 180 individuals (60 per breed). There were differences in microbial diversity among different sheep breeds (P < 0.05). Principal coordinate analysis showed that the three varieties were separated, but also partially overlapped. Linear discriminant analysis effect size identified a total of 19 biomarkers in three breeds. Of these biomarkers, five in Hu sheep were significantly negatively correlated with average feed conversion rate (P < 0.05). Six biomarkers were identified in the rumen of Dorper sheep, among which Ruminococcus was significantly positively correlated with body weight at 80 d (P < 0.05). In Tan sheep, Rikenellaceae_RC9_gut_group was significantly positively correlated with meat fat, and significantly positively correlated with volatile fatty acids (VFAs), such as butyric acid and isobutyric acid (P < 0.05). The Rikenellaceae_RC9_gut_group may regulate Tan mutton fat deposition by affecting the concentration of VFAs. Functional prediction revealed enrichment differences of functional pathways among different sheep breeds were small. All were enriched in functions, such as fermentation and chemoheterotrophy. The results show that there are differences in the rumen microorganisms of the different sheep breeds, and that the microorganisms influence the host.

The rumen is the most important digestive organ of ruminants, and the rumen microflora plays an important role in the process of digestion. This study compared the differences in rumen microbes of different breeds of sheep, identified key biomarkers of each breed, and analyzed their correlation with important economic traits of sheep. The results showed that the biomarkers of various breeds were significantly correlated with key traits. Therefore, we believe that there is a link between sheep rumen microbes and the differential traits of different breeds of sheep. This provides a new idea for sheep trait improvement.

Amino acids metabolism by rumen microorganisms: Nutrition and ecology strategies to reduce nitrogen emissions from the inside to the outside.

For the ruminant animal industry, the emission of nitrogenous substances, such as nitrous oxide (N2O) and ammonia (NH3), not only challenges environmental sustainability but also restricts its development. The metabolism of proteins and amino acids by rumen microorganisms is a key factor affecting nitrogen (N) excretion in ruminant animals. Rumen microorganisms that affect N excretion mainly include three types: proteolytic and peptidolytic bacteria (PPB), ureolytic bacteria (UB), and hyper-ammonia-producing bacteria (HAB). Microbes residing in the rumen, however, are influenced by several complex factors, such as diet, which results in fluctuations in the rumen metabolism of proteins and amino acids and ultimately affects N emission. Combining feed nutrition strategies (including ingredient adjustment and feed additives) and ecological mitigation strategies of N2O and NH3 in industrial practice can reduce the emission of nitrogenous pollutants from the ruminant breeding industry. In this review, the characteristics of the rumen microbial community related to N metabolism in ruminants were used as the metabolic basis. Furthermore, an effective strategy to increase N utilisation efficiency in combination with nutrition and ecology was reviewed to provide an inside-out approach to reduce N emissions from ruminants.

Metabolism, Ketosis Treatment and Milk Production after Using Glycerol in Dairy Cows: A Review.

The aim of this paper is to review and systematize the current state of knowledge on glycol metabolism in cattle. Glycerol, derived from biodiesel production, must be purified in order to be a useful product for feeding livestock. The use of glycerol in the feeding of ruminants can be justified for several reasons: (i) it is a source of energy in the ration, (ii) it is a glucogenic precursor, and (iii) it may have an effect on milk composition. The high energy value of glycerol provides the opportunity to use this raw material as a partial grain substitute in cattle feed rations. Dietary supplementation of glycerol is associated with increased propionate, butyrate, valerate, and isovalerate concentrations in the rumen. Glycerol can be used at up to 10%-15% of the dietary dry matter (DM) and is well-established as a treatment for ketosis in cows. Glycerol increases plasma glucose and may reduce non-esterified fatty acids and ß-hydroxybutyrate levels. The use of glycerol does not have a clear effect on DM intake, milk yield, or milk composition. However, some authors have reported an increase in milk yield after glycerol supplementation associated with decreased milk fat concentration. It is also possible that the concentration in the milk of odd-chain fatty acids and cis-9, trans-11 conjugated linoleic acid may increase after glycerol application.

Dried Rumen Digesta Pellet Can Enhance Nitrogen Utilization in Thai Native, Wagyu-Crossbred Cattle Fed Rice Straw Based Diets.

The goal of the current research was to study the effects of a diet of dried rumen digesta pellets (DRDP) on diet utilization, ruminal microorganisms, and ruminal microbes in Thai native, Wagyu-crossbred cattle. Four Thai native, Wagyu-crossbred, beef cattle were assigned to a 4 × 4 Latin square design to supplement DRDP levels at 0, 50, 100, and 150 g/d, respectively. Rice straw intake, total intake, and estimated energy intake varied significantly among the different DRDP levels. Nitrogen intake, apparent N absorption, and apparent N retention were significantly enhanced when compared to the 0 g/d DRDP. DRDP supplementation at 150 g/d produced the greatest apparent digestibility of crude protein compared to the group that was not fed DRDP. Supplementation of DRDP did not alter the population of protozoa, whereas the addition of 150 g DRDP significantly increased the fungal zoospore. Supplementation of DRDP at various levels did not change the concentration of volatile fatty acid (VFA) or the VFA profiles. Thus, DRDP could be an alternative strategic supplement for Thai-native, Wagyu-crossbred cattle in order to enhance N utilization and fungal zoospores.