Rumen Population Research Articles

Environmental Driving of Adaptation Mechanism on Rumen Microorganisms of Sheep Based on Metagenomics and Metabolomics Data Analysis.

Natural or artificial selection causes animals to adapt to their environment. The adaptive changes generated by the rumen population and metabolism form the basis of ruminant evolution. In particular, the adaptive drive for environmental adaptation reflects the high-quality traits of sheep that have migrated from other places or have been distant from their origins for a long time. The Hu sheep is the most representative sheep breed in the humid and low-altitude environments (Tai Lake region) in East Asia and has been widely introduced into the arid and high-altitude environments (Tibetan Plateau and Hotan region), resulting in environmental adaptive changes in the Hu sheep. In this study, a joint analysis of the rumen microbial metagenome and metabolome was conducted on Hu sheep from different regions (area of origin and area of introduction) with the objective of investigating the quality traits of Hu sheep and identifying microorganisms that influence the adaptive drive of ruminants. The results demonstrated that the growth performance of Hu sheep was altered due to changes in rumen tissue and metabolism following their introduction to the arid area at relatively high altitude. Metagenomic and metabolomic analyses (five ramsper area) revealed that 3580 different microorganisms and 732 different metabolites were identified in the rumen fluid of arid sheep. Among these, the representative upregulated metabolites were 4,6-isocanedione, methanesulfonic acid and N2-succinyl-L-arginine, while the dominant microorganism was Prevotella ruminicola. The downregulated metabolites were identified as campesterol, teprenone and dihydroclavaminic acid, while the disadvantaged microorganisms were Dialister_succinatiphilus, Prevotella_sp._AGR2160, Prevotella_multisaccharivorax and Selenomonas_bovis. The results of the Pearson analysis indicated that the rumen microbiota and metabolite content of sheep were significantly altered and highly correlated following their relocation from a humid lowland to an arid upland. In particular, the observed changes in rumen microorganisms led to an acceleration of body metabolism, rendering sheep highly adaptable to environmental stress. Prevotella_ruminicola was identified as playing an important role in this process. These findings provide insights into the environmental adaptation mechanisms of sheep.

Effects of Saccharomyces cerevisiae and Bacillus subtilis on in vitro fermentation in the rumen of Hu sheep.

The demand for animal products is increasing in developing countries due to population growth. However, livestock production contributes significantly to global warming, accounting for 25%. Probiotics can help improve livestock efficiency by enhancing gut microbes and fat metabolism. They can modify rumen populations, enhance fermentation, reduce methane emissions and improve feed digestion. In this study, the goal was to determine the most effective method of reducing methane emissions in the rumen of sheep in vitro by adding different concentrations of Saccharomyces cerevisiae and Bacillus subtilis. Adding 8 × 106 CFU g-1 S. cerevisiae during fermentation reduced pH levels after 48 h. This also increased the concentrations of NH3-N, microbial protein and total gas production. At the same time, it decreased methane emissions. Furthermore, adding 20 × 106 CFU g-1 B. subtilis to the mixture increased total gas production (TGP) and methane production, with the highest production observed after 48 h. However, it did not affect pH levels after 48 h. It can be concluded that S. cerevisiae had significantly increased microbial protein and NH3-N concentrations after fermentation without altering pH. Additionally, the addition of S. cerevisiae enhanced TGP and reduced methane emissions. It is worth noting that TGP increased because B. subtilis was added at a concentration of 20 × 106 CFU g-1, with no significant differences between concentrations. Therefore, we recommend adding S. cerevisiae and B. subtilis to the diet at doses of 8 and 20 × 106 CFU g-1, as it resulted in higher TGP and reduced methane emissions. © 2024 Society of Chemical Industry.

The addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in ruminants

Abstract. Agustina S, Wiryawan KG, Suharti S, Meryandini A. 2024. The addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in ruminants. Biodiversitas 25: 107-115. Rumen microbes have an important role in the rumen. Anaerobic fungi are microbes needed in the forage digestion process in the rumen. The addition of microbes, particularly anaerobic fungi is essential to increase the digestibility of forage within rumen. Therefore, this study aimed to evaluate the addition of anaerobic fungi isolates from buffalo rumen to increase fiber digestibility, fermentation, and microbial population in sheep rumen. The in vitro tests were carried out using the Tilley and Terry method, using elephant grass and rice straw as tested forage. Piromyces sp. (F1, and F3), Caecomyces sp. (F2, and F5), and Neocallimastix frontalis (F4) isolates from buffalo rumen were used as tested anaerobic fungi. The result showed that the addition of anaerobic fungi isolates from buffalo rumen significantly affected fiber digestibility (Neutral Detergent Fiber (NDF), Acid Detergent Fiber (ADF), cellulose and hemicellulose) except lignin digestibility. The addition of N. frontalis had higher fiber digestibility which is 49.02% NDF digestibility, 42.11% ADF digestibility, 44.28% hemicellulose digestibility, and 38.60% cellulose digestibility. Furthermore, N. frontalis also significantly increased In vitro Dry Matter Digestibility (IVDMD), In vitro Organic Matter Digestibility (IVOMD), ammonium (NH3) production, total Volatile Fatty Acid (VFA) production, and microbial population compared to Piromyces sp., and Caecomyces sp. In conclusion, anaerobic fungus type N. frontalis showed promising potential to be used as a ruminant probiotic due to its superior effect on fiber digestibility, fermentation, and microbial population compared to Caecomyces sp. and Piromyces sp.

Enhancing the Conventional Culture: the Evaluation of Several Culture Media and Growth Conditions Improves the Isolation of Ruminal Bacteria

The rumen microbiota is critical in cattle digestion. Still, its low cultivability makes it difficult to study its ecological function and biotechnological potential. To improve the recovery of ruminal microorganisms, this study combined the evaluation of several cultivation parameters with metabarcoding analysis. The parameters tested comprised eight media cultures, three sample dilutions (10−2, 10−6, 10−12), and two incubation times (3 and 7 days). Bacterial populations were determined through Illumina sequencing of 16S rRNA from three biological replicates. The results indicate that none of the culture media recovered all rumen populations and that there was an altered relative abundance of the dominant phyla. In the rumen, Bacteroidetes and Firmicutes comprised 75% and 15% of the relative abundance, respectively, while in the culture media, these were 15% and 60%, respectively. Principal coordinate analysis (PCoA) of the bacterial community revealed significant shifts in population composition due to dilution, with 10−2 and 10−6 dilutions clustered closely while the 10−12 dilution differed markedly. In contrast, incubation duration did not influence population diversity. According to the results, two media, CAN and KNT, were selected based on their ability to recover more similar populations compared to the rumen sample. The metataxonomic study showed that CAN media had consistent reproducibility over time, while KNT showed enrichment of different taxa due to the use of rumen fluid as a substrate. From these, 64 pure cultures were obtained and 54 were identified through 16S rRNA gene sequencing. Being Streptococcus the most frequently isolated genus, this prevalence contrasts with the liquid media composition, underscoring the importance of refining single colony isolation strategies. Although no culture medium could replicate the native rumen bacterial population perfectly, our findings highlight the potential of CAN and KNT media in recovering populations that are more closely aligned to natural rumen conditions. In conclusion, our study emphasizes the importance of integrating molecular approaches in selecting suitable cultivation media and parameters to depict rumen bacteria accurately.

A Comparison of Three Artificial Rumen Systems for Rumen Microbiome Modeling

The rumen contains a complex mixture of microbes, crucial for the animal’s ability to degrade feed. Some of the feed-derived carbon is released as methane, a potent greenhouse gas, into the atmosphere. There is growing interest in reducing the loss of feed-derived carbon, making it available to the animal and improving animal productivity. Artificial rumen systems (ARSs) have been widely used to evaluate novel feed additives in terms of their ability to reduce methane production in the rumen and their effect on the rumen microbiome function prior to conducting resource-intensive animal trials. While the value of ARSs is widely acknowledged, it remains unclear which of these in vitro systems simulate the natural system most accurately. Here, we evaluated three different ARSs and compared them to in vivo rumen metrics. The results showed that all systems were capable of maintaining stable pH, redox potential, and temperature over time. The batch-style ARS simulated the rumen over 48 h. The semi-continuous ARS mimicked the volatile fatty acid profile and microbiota of the in vivo rumen for up to 120 h. Similarly, all ARSs maintained the prokaryotic and eukaryotic rumen populations over the duration of the study, with the semi-continuous ARS maintaining the natural rumen microbiome more accurately and for up to 120 h. In sum, our results suggest that three of the widely used ARSs simulate the rumen ecosystem adequately for many short-term rumen microbiome studies, with the more advanced semi-continuous ARS being more accurate when rumen simulation is extended to over 48 h.

Effects of wheat bran replacement with pomegranate seed pulp on rumen fermentation, gas production, methanogen and protozoa populations of camel and goat rumen using competitive PCR technique: An in vitro study.

Microbial populations in the rumen play an essential role in the degradation of Cellulosic dietary components and in providing nutrients to the host animal. This study aims to detect the effect of pomegranate seed pulp (PSP) on rumen fermentation, digestibility and methanogens and the protozoa population (by competitive polymerase chain reaction [PCR]) of the camel and goat rumen fluid. PSP was added to the experimental treatments and replaced by wheat bran (0%, 5% and 10%). Rumen fluid was collected from three goats and two camels according to the similarity of sex, breed, origin and time and used for three gas production studies. DNA extraction was performed by the RBB+c method, the ImageJ programme calculated band intensities (target and competing DNA), and line gradients were plotted based on the number of copies and intensity. Our result showed that diets did not significantly affect the methanogen and protozoa population. Animal species affected microbial populations so that both populations in camels were less than goats. The production of gas and volatile fatty acids was not affected by diets. These two parameters and NH3 concentration and methane production in goats were higher than in camel. The pH of digested dry matter and microbial protein in camels was higher than in goats. Therefore, the competitive PCR technique is an effective method for enumerating rumen microbiota. This supplementation can be considered a strategy to achieve performance and environmental benefits.

Intake, digestibility and ruminal parameters of lambs fed with increasing levels of wheat bulgur.

The aim was to evaluate the effect of the inclusion of wheat bulgur in the diet on intake, digestibility, N balance and ruminal parameters in cannulated lambs. Four castrated Santa Ines×Dorper lambs, cannulated in the rumen, (45 ± 9 kg) were housed in metabolism crates. They were randomly distributed in a 4×4 Latin Square,10-day adaption, a 6-day sampling period. The base diet was composed by ryegrass hay and concentrate, in a 40:60 roughage:concentrate ratio and four inclusions of wheat bulgur on the total diet: 0, 190, 380 and 570 g/kg dry matter. The inclusion of wheat bulgur did not affect the intake of non-structural carbohydrates. The intake of dry matter, fiber, crude protein, organic matter and crude fat decreased linearly (P<0.05). The digestibility of neutral detergent fiber decreased linearly (P=0.001). The N retained and the excreted in urine were not affected by wheat bulgur inclusion. Fecal excretion, total excretion and absorbed N, decreased linearly (P<0.05). There was no change on pH, ammonia, soluble carbohydrates and protozoa population in rumen. Increasing of wheat bulgur in the diet of lambs decrease the nutrient intake and fiber digestibility without affecting the digestibility of other compounds, ruminal parameters, and the protozoa count.

Populasi Mikroba Rumen, Fermentabilitas, dan Kecernaan Suplementasi Daun Kelor dalam Ransum Sapi Perah secara In Vitro

This study aimed to evaluate the microbial rumen population, fermentability, and digestibility of Moringa leaf supplementation in dairy cow ration using in vitro and to determine the optimal level of supplementation. The experiment consist of two steps with the first step was microbiology measurement used a Randomized Block Design with 5 treatments level of Moringa leaf extract (P0= control; P1= 5%, P2 = 10%, P3 =15%, P4 =20%) and the second step was in vitro fermentability and digestibility measurement used Randomized Block Design with 7 treatments level of Moringa leaf in dairy cow ration (R0 = control, R1 = R0 + 2.5% Moringa leaf, R2= R0 +5% Moringa leaf, R3 = R0 + 7.5% Moringa leaf, R4= R0+10% Moringa leaf, R5=R0+12.5% Moringa leaf, R6=R0+15% Moringa leaf) which grouped by rumen fluids. Data analysis used analysis of variance and continued with Duncan’s Multiple Range Test. The measured variable were microbial rumen population (bacteria and protozoa), fermentability (N-NH3, VFA), microbial protein synthesis, dry matter digestibility (DMD), and organic matter digestibility (DMO). The results showed Moringa leaf extract significantly decreased bacterial population (p&lt;0.05), but there was no effect on the protozoa population. Moringa leaf supplementation did not affect N-NH3, DMD, and DMO, but significantly influenced VFA concentration and microbial protein synthesis (p&lt;0.01). The higher Moringa leaf supplementation showed decreasing total VFA concentration, but was still within the normal range for rumen fermentation (102.29-126.69 mM). Moringa leaf supplementation showed a quadratic effect on microbial protein synthesis with an optimal supplementation level of 5%, but decreasing at a level of 7.5% still within in normal range. It can be concluded Moringa leaf can be supplemented up to 7.5% in dairy cow ration.&#x0D; Key words: digestibility, fermentability, in vitro, moringa leaf, dairy cow

Exploring the relationship between bacterial genera and lipid metabolism in bovine rumen

The rumen is characterised by a complex microbial ecosystem, which is particularly active in lipid metabolism. Several studies demonstrated a role of diet and breed on bacterial community profile, with the effect on metabolic pathways. Despite the knowledge achieved on metabolism and the bacterial profile, little is known about the relationship between individual bacteria and metabolic pathways. Therefore, a multivariate approach was used to search for possible relationships between bacteria and products of several pathways. The correlation between rumen bacterial community composition and rumen lipid metabolism was assessed in 40 beef steers (20 Maremmana and 20 Aubrac) reared with the same system and fed the same diet. A canonical discriminant analysis combined with a canonical correlation analysis (CCA) was performed to explore this correlation. The variables showing a Pearson correlation higher than 0.6 as absolute value and significant were retained for CCA considering the relationship of bacterial composition with several metabolic pathways. The results indicated that some bacterial genera could have significant impacts on the presence of several fatty acids. However, the relationship between genera and fatty acid changes according to the breed, demonstrating that the metabolic pathways change according to the host genetic background, related to breed evolution, although there is also an intra-breed genetic background which should not be ignored. In Maremmana, Succiniclasticum and Rikenellaceae_RC9_gut_group showed a high positive correlation with dimethylacetals (DMAs) DMAC13:0, DMAC14:0, DMAC14:0iso, DMAC15:0, DMAC15:0iso, and DMAC18:0. Prevotellaceae_UCG-003 correlates with C18:3c9c12c15 and C18:1t11, while Fibrobacter and Succiniclasticum correlate with C18:2c9t11 and Lachnospiraceae_NK3A20_group correlates with C18:1c12. Prevotellaceae_UCG-003, Ruminococcaceae_UCG-010, and Oribacterium showed a positive correlation with C13:0iso, and C17:0. Conversely, in Aubrac, Treponema_2 and Rikenellaceae_RC9_gut_group correlated with DMAC14:0iso, DMAC16:0iso, DMAC17:0iso, while Ruminococcaceae_UCG-010, Christensenellaceae_R-7_group and Ruminococcaceae_NK4A214_group correlated with DMAC18:1t11, DMAC14:0, DMAC18:1c12. Acetitomaculum correlated with C18:2c9c12, C18:1c12, C18:1c13, C18:1t12 and Lachnospiraceae_NK3A20_group with C18:1t6-8 and C18:1t9. Saccharofermentas, Ruminococcaceae_UCG-010 and Rikenellaceae_RC9_gut_group correlated with C18:2c9t11 while, Prevotellaceae_UCG-001 and Ruminococcus_1 correlated with C14:0iso, C15:0, C15:0iso, C17:0. Saccharofermentans, Rikenellaceae_RC9_gut_group, Ruminococcaceae_NK4A214_group, and Ruminococcaceae_UCG-010 correlated with C13:1c12 and C16:0iso. These results lead to hypothesise a possible association between several metabolic pathways and one or a few bacterial genera. If these associations are confirmed by further investigations that verify the causality of a bacterial genus with a particular metabolic process, it will be possible to deepen the knowledge on the activity of the rumen population in lipid metabolism. This approach appears to be a promising tool for uncovering the correlation between bacterial genera and products of rumen lipid metabolism.

Characterization and Comparison of the Rumen Luminal and Epithelial Microbiome Profiles Using Metagenomic Sequencing Technique.

Bacterial dysbiosis as a result of nutritional, bacterial, viral, and parasitic gastrointestinal infections can adversely affect the metabolism, productivity, and overall health of cattle. The purpose of this project was to characterize the commensal microbiota present in two locations of the rumen concomitantly in vivo with the animals undergoing habitual husbandry, as it was hypothesized that there are major differences in the commensal microbiota present in the two locations of the adult bovine major forestomach. A surgically fitted rumen cannula was used to allow ruminal lumen contents and mucosal biopsies to be collected from six crossbred yearling steers. In order to assess as much environmental and individual steer microbiota variation as possible, each animal was randomly sampled three times over a 3 week period. 16S rRNA sequencing was performed to provide a detailed descriptive analysis from phylum to genus taxonomic level. Significant differences were observed between luminal and epimural bacterial populations in the bovine rumen. As expected, a core microbiome composed by Firmicutes and Bacteroidetes represented over 90% of the microbiome, however, further analysis showed distinct diversity and distribution of the microbiome between the two locations. Characterizing the gastrointestinal microbiome in vivo is imperative. The novelty and the contribution of this study to the literature is the use of live cattle which allowed real-time sample collections and analysis of the rumen microbiome providing an understanding of what is normal in the live animal.

Isolation, identification and characterization of rumen bacteria and estimation of their fibre degradable enzymes in yak (Bos grunniens)

To utilize the plant nutrients efficiently, rumen microbes play a great role in the livestock, acting as a source of energy. Like other ruminants, the yak rumen harbours different microorganisms that are responsible for bioconversion of nutrients into a source of energy for the animals. The samples of rumen liquor were collected from the yak (Bos grunniens) rumen. The specific media was made to culture the rumen microbes and isolated the pure culture with serial dilution. The pure colony was identified with the help of 16S ribosomal gene sequencing. The enzyme activity of the isolates was observed by estimating the enzymes like Carboxymethyl Cellulase (CMCase) and Avicilase. The isolates were identified with the help of specific primer (Fibrobactor succinogen) and characterized which were closely related to Bacteroides pyogenes and Ruminococcus species. The study indicates diverse group of rumen bacterial population in yak rumen. Fibrobactor succinogen, Ruminococcus and Bacteroides species take potential roles as source of microbial enzyme for degradation of feed and fodder in yaks.

Changes in vitro rumen fermentation, methane production and microbial populations in response to green tea extract

This research was conducted to evaluate the influence of adding increasing levels (0, 250, 500,750, and 1000 μg/mL buffered rumen fluid) of green tea ethanol extract (GTEE) to a basal substrate (50% roughage: 50% concentrate formulated with 50% barley and 50% corn grain) on rumen fermentation, methane emissions, and population of microorganism under in vitro experiment. The potential of gas production (A), methane emission, and methane ratio (mL/mL total gas 24 h) were linearly decreased by increasing the dose of GTEE (p<.001). The control group has the highest methane emission (p<.05), while it was the lowest (p<.05) at a dose of 1000 GTEE (47.74 versus 24.23 mL/g DM). In vitro digestibility of dry and organic matter were negatively affected by GTEE (L and Q; p<.001). The addition of GTEE significantly decreased total volatile fatty acids (TVFA) and N-NH3 concentration (L, p<.001), and also changed the VFA profile compared to the control group by decreasing and increasing the acetate and the propionate proportions (p<.001). The highest decrease in total protozoa population (93%), total fungi (38%), and methanogenic archaea (95%) compared to the control group was observed at the highest dose (1000) of GTEE. The addition of GTEE stimulates the population of Prevotella ruminicola and Selenomonas ruminantium, but Butyrivibrio fibrisolvent population was inhibited, in different supplementation doses. The lowest supplementation level (250 μg/mL) seems to have the most benefits on the in vitro fermentation parameters with minimum negative effects on nutrient digestibility. It can be concluded that GTEE can potentially be used to manipulate ruminal fermentation patterns. Highlights Reducing the methane concentration through the anti-protozoal activity of green tea extract improve rumen fermentation patterns by decreasing acetate and N-NH3 concentration and increasing the propionate proportions. Although the in vitro anti-acidosis potential of GTEE is not as much as monensin, the anti-acidosis potential is significantly increased by increasing GTEE dose compared to the control. The decrease in in vitro total gas, CH4 production, and dry- and organic-matter digestibility on the addition of GTEE could be attributed to the antimicrobial action of GTEE.

Effect of sole maize and maize –lablab silage on the ruminal volatile fatty acids (VFAS) of grazing calves in the dry season

Silages of sole maize and mixtures of maize-lablab were made at harvest in plastic bags. The experimental Unit consists of twelve cross-bred yearling bulls (White Fulani x N’dama) calves weighing 71-72kg and were randomly allotted to three dietary treatments: Grazing + sole maize silage, Grazing + mixtures of maize-lablab silage and Unsupplemented grazing as control. The experimental design was a completely randomized design and lasted 84days. Silage diets were given between 07:30 and 11:00 hours daily before grazing. Rumen fluid was collected at the end of the study to evaluate the co-efficient of ruminal fluid. The crude protein content in sole maize silage was half of that in mixture of maize-lablab silage. Inclusion of lablab in maize stover silage increased the mineral content as well as the lignin fraction. The mean pH value of sole maize silage (3.80) was less (P &lt; 0.05) than 4.25 obtained with addition of lablab. The buffering capacity (5.37%) of sole maize silage significantly (P &lt; 0.05) increased to 5.71% in mixture of maize-lablab silage. Lactic acid contents differed was influenced significantly (P &lt; 0.05) with a mean value of 8.4% and 8.5% respectively in the sole maize silage and with lablab inclusion. Total volatile fatty acid (VFA) ranged from 56.7 μmoles/ml in calves without supplementation to 95.2 μmoles/ml in the calves fed mixture of maize-lablab silage. Mixture of Maize-lablab silage had the highest values for all the minerals determined in the feed materials while sole maize had the least. It was concluded from this trial, that forage legumes are relatively good sources of degradable nitrogen and fermentable energy, so their inclusion in the diet is likely to increase the rumen population of cellulolytic microbes and also proves that, mixture of maize-lablab silage could be used as supplement to enhance the growth and survival of calves during the dry season, when animal feeds are relatively scarce.

EXPLORING THE METABOLICALLY ACTIVE RUMEN MICROBIOTA AND ITS FIBROLYTIC POTENTIAL IN CROSSBRED CATTLE FED ON FIBROUS DIET THROUGH METATRANSCRIPTOMICS

The rumen wharves conglomerate of symbiotic fibrolytic microflora with the potential to produce repertoire of carbohydrate-active enzymes to elicit the degradation of recalcitrant plant lignocellulosic complex into simpler forms that can be utilized by the host. A metatranscriptomics approach was adopted to explore the metabolically active microbiota and the transcripts involved in the deconstruction of lignocellulose in Indian crossbred cattle rumen. The experimental animals were fed with mixed diet for a period of twenty-one days and the total RNA was isolated from the rumen digesta using a modified total RNA extraction protocol. After mRNA enrichment, the cDNA libraries were subjected to sequencing under Illumina HiSeq platform and generated about 2.89 GB of raw sequences. The contig assembly was accomplished using two different tools and the redundant sequences were removed before further processing. A total of 133,930 orfs were predicted from the assembled contigs using MetaGeneMark tool and the taxonomic affiliation of orfs were achieved using MEGAN 6.0 Community Edition. A total of 17 bacterial, 5 eukaryotic and 1 archaeal phylum were identified from rumen metatranscriptomic dataset. Phylum Bacteroidetes were acknowledged as the most abundant and metabolically active rumen bacterial populations in cattle rumen with 36,414 orfs corresponding to it, followed by Firmicutes with 6,349 orfs. Further, MEGAN annotation of metatranscriptomic data at species level revealed that Prevotella brevis and Prevotella ruminicola as the most metabolically active bacterial populations representing 4,022 and 2,725 orfs each. The functional annotation of metatranscriptomic data using COG database revealed that a large number of transcripts (~16%) were corresponding to translation, ribosomal structure and biogenesis and carbohydrate transport and metabolism (15%). dbCAN annotation of rumen metatranscriptomic data identified and classified 5,267 transcripts belonging to 168 CAZyme families (GH-52%, GT-26%, CBM-14%, CE-6%, PL-2% and AA-0%). The microbial community analysis of the CAZyme encoding transcripts using M5NR database revealed that a significant proportion of CAZymes were contributed by genera Prevotella (37%) and Bacteroides (21%). The cattle rumen microbiome metatranscriptome analysis presented in this study facilitated the detection of large number of transcripts encoding diverse CAZymes that actively take part in the hydrolysis of plant lignocellulose complex that may be useful for improving livestock and biofuel generation.

Effect of diets containing oak kernel on the rumen fermentation and digestibility, blood metabolites and liver enzymes in Khuzestani buffalo

This study was conducted to investigate the effect of different levels of oak kernel on rumen digestibility and fermentation, blood metabolites and liver enzymes of Khuzestani buffalo. Sixteen male buffaloes, one year old were fed with experimental diets containing different levels of oak kernel (0, 15.8%, 31.58% and 47.37% equal to 0, 1.5, 3 and 4.5% tannin, respectively) in a completely randomized design for 35 days. In end of experiment, dry matter intake, digestibility, rumination behaviour, rumen and blood parameters were measured. The results showed that oak kernel increased dry matter intake and digestibility of dry matter and organic matter but the digestibility of protein, NDF and ADF was decreased. Incorporation of 47.37% oak kernel in the diet caused significant decrease in ammonia- N and protozoa population of buffalo rumen, but pH and total fatty acids were not affected. The rumination activity in diet containing 47.37% oak kernel was the lowest. With the increasing oak kernel in the buffalo diet, blood cholesterol level decreased, but there were no significant changes in blood glucose, urea, triglycerides, alkaline phosphatase, aspartate and alanin amino transferase enzymes between the experimental treatments. Therefore, even if the digestibility of ADF and CP decreased by adding of oak kernel but the using of oak kernel up to 47.37% in buffalo diet had no negative effect on the rumen fermentation characteristics, digestibility and blood metabolites, hence it may be used in buffalo’s diet.

Observações clínicas, hematologia e características do fluido ruminal de bovinos de corte recebendo dieta "Max Beef" grão inteiro

Este estudo propôs caracterizar os efeitos da alimentação baseada na dieta do grão de milho inteiro na dinâmica de parâmetros clínicos e metabólitos bioquímicos de bovinos confinados. Foram utilizados 20 bovinos, sem raça definida, adultos, com peso médio de 300 kg, divididos em dois grupos experimentais. O grupo experimental (G1; n=15), composto por animais alimentado somente dieta “Max Beef” Grão Inteiro e o grupo controle (G2; n=5), composto por animais, alimentado com bagaço de cana e a dieta “Max Beef” Grão Inteiro, na proporção 30:70. Todos os animais foram submetidos às observações clínicas, colheita de sangue por venopunção jugular e fluido ruminal. Os animais do grupo G1 (Dieta “Max Beef” Grão Inteiro) apresentaram movimentos ruminais incompletos, timpania ruminal branda e diarreia com grãos de milho inteiro. Não foram registradas alterações hematológicas nem na concentração de fibrinogênio. Apresentaram menor valor de pH ruminal durante todo o período experimental, com comprometimento da população de infusórios, diminuição da prova de redução do azul de metileno e tempo de sedimentação e flotação ausente. Conclui-se que dietas para bovinos de corte contendo “Max Beef” Grão Inteiro provoca acidose crônica ruminal e compromete as características físico-químicas e microbiológicas do fluido ruminal.

Effect of Dried Leaves of Leucaena leucocephala on Rumen Fermentation, Rumen Microbial Population, and Enteric Methane Production in Crossbred Heifers

Simple SummaryThe objective of the experiment was to evaluate the effects of dietary supplementation of heifers with increasing levels of dried Leucaena leucocephala leaves (DLL) on nutrient digestibility, fermentation parameters, microbial rumen population, and production of enteric methane (CH4). Nutrient digestibility decreased with increasing levels of DLL in the ration. Inclusion of DLL did not have detrimental effects on rumen pH, rumen microbial community, and volatile fatty acids proportions. Enteric CH4 emissions in heifers were reduced with increasing levels of DLL in the ration.The effects of dietary inclusion of dried Leucaena leucocephala leaves (DLL) on nutrient digestibility, fermentation parameters, microbial rumen population, and production of enteric methane (CH4) in crossbred heifers were evaluated. Four heifers were used in a 4 × 4 Latin square design consisting of four periods and four levels of inclusion of DLL: 0%, 12%, 24%, and 36% of dry matter (DM) intake. Results showed that DM intake (DMI), organic matter intake, and gross energy intake (GEI) were similar (p > 0.05) among treatments. Apparent digestibility of organic matter, neutral detergent fiber, and energy decreased with increasing levels of DLL in the ration (p < 0.05). In contrast, digestible crude protein (CP) was higher (p < 0.05) in treatments with 12% and 24% DM of DLL. The inclusion of DLL did not affect (p > 0.05) rumen pH and total volatile fatty acids. Rumen microbial community was not affected (p > 0.05) by treatment. There was a linear reduction (p < 0.05) in CH4 emissions as the levels of DLL in the ration were increased. Results of this study suggest that an inclusion of 12% DM of ration as DLL enhances digestible CP and reduces daily production of enteric CH4 without adversely affecting DMI, rumen microbial population, and fermentation parameters.

82 Effect of by-product feed supplementation of a hay-based diet on rumen fermentation, diet digestibility, methane production and protozoal population in an artificial rumen (RUSITEC)

Abstract This study investigated the effects of adding sunflower screenings, flax screenings and quinoa to a hay-based diet on ruminal fermentation, DM digestibility (DMD) and enteric methane (CH4) production in an artificial rumen system (RUSITEC). The experiment was a RCBD with 4 treatments assigned to 16 fermentation vessels (n = 4/treatment) in 2 RUSITEC apparatuses. The control diet was 100% hay, with treatments consisting of sunflower screenings, flax screenings and quinoa dockage at inclusion rates of 1.10, 1.38, and 1.59 g DM, respectively. The study period was 15 d, with an 8-d adaptation and 7-d sample collection period. Data were analyzed using the PROC MIXED procedure of SAS with fixed effects of treatment, day of sampling and their interaction as fixed effects. Compared to control, the addition of sunflower screenings decreased (P = 0.020) CH4produced per g of DM digested (10.43 vs. 7.88 mg/g DMD). Inclusion of sunflower screenings reduced (P &amp;lt; 0.01) DMD (67.6 vs. 57.8 %) and the number of protozoa (2.2x104vs. 1x103ml) compared to the control. The addition of flax screenings versus the control diet increased (P = 0.001) CH4produced per g of DMD (10.43 vs. 15.05 mg/g). However, inclusion of flax screenings resulted in a decrease (P &amp;lt; 0.05) in DMD and number of protozoa compared to the control (1.07x103vs. 2.2x104ml, 64.33 vs. 67.64 %, respectively). The addition of flax screenings decreased DMD (P = 0.04). Quinoa inclusion had no effect on DMD or protozoa count, while CH4production increased (P = 0.0003) compared to the control (15.15 vs 10.43 mg/g DMD). Disappearance of NDF did not differ between treatments (P = 0.72). Inclusion of sunflower screenings and quinoa did not affect molar proportions of propionate or and butyrate, while decreased (P &amp;lt; 0.05) by adding flax screenings. In conclusion, the addition of sunflower screenings provided the greatest potential to reduce CH4 emissions associated with supplemented hay-based diets.

PSXIV-16 Comparative in vitro effects of spray-dried and freshly-harvested Paenibacillus fortis strain 79R4 on rumen methane, nitrate, nitrite and ammonia metabolism

Abstract Nitrate supplementation into the ruminant diet can decrease ruminal methane emissions, but amounts needed to achieve appreciable decreases can risk ruminal accumulations of nitrite with potential for methemoglobinemia. A denitrifying rumen Paenibacillus fortis strain 79R4 (79R4) selected for enhanced nitrite-metabolizing ability has shown promise as a probiotic to decrease risks of nitrite toxicosis. Presently, a spray-dried prototype of this spore-forming, facultative anaerobe was tested during anaerobic culture (10 mL/tube) of rumen fluid freshly-collected from an alfalfa hay-fed cannulated Jersey cow. Cultures supplemented with 22 mM sodium nitrate and without or with inoculations of freshly-harvested (FH) cells or spray dried (SP) 79R4 spores (3 tubes/treatment; 108 cells/spores per tube) were cultured anaerobically (39oC for 24 h with 100% CO2). The FH- and SP- cells were grown aerobic, 72 h in tryptic soy broth, SP- cells were then processed and spray-dried. Nitrate-supplementation decreased (P = 0.0006; SEM = 0.31) methane production by the cultures, but this decrease was unaffected by 79R4 inoculation (2.57 µmol CH4/mL with no nitrate/no inoculum versus 0.15 µmol CH4/mL with nitrate/inoculum). Nitrate-metabolizing activity in nitrate-treated cultures were unaffected by 79R4 inoculations (P = 0.17; SEM = 0.15), rates being 0.95, 0.63 and 0.50 µmol nitrate/mL h-1 FH-, SP- and non-inoculated cultures, respectively. Nitrite accumulation rates (P = 0.10; SEM = 0.06) and peak nitrite concentrations (P = 0.06; SEM = 0.75) tended to be lower in SP- than in FH- and non-inoculated cultures (0.29, 0.47 and 0.47 µmol nitrite/mL h-1 and 3.33, 5.67 and 5.66 µmol/mL, respectively). Rates of ammonia accumulation were more rapid (P = 0.01; SEM = 0.01) in SP- and FH- than in non-inoculated cultures (0.16 and 0.15 versus 0.06 µmol/mL h-1, respectively). Results provide evidence that 79R4 prototype may aid rumen populations in detoxifying nitrite, therefore enhancing the abilities of high nitrate diets.

Metatranscriptomics reveals mycoviral populations in the ovine rumen.

The rumen is known to contain DNA-based viruses, although it is not known whether RNA-based viruses that infect fungi (mycoviruses) are also present. Analysis of publicly available rumen metatranscriptome sequence data from sheep rumen samples (n=20) was used to assess whether RNA-based viruses exist within the ovine rumen. A total of 2466 unique RNA viral contigs were identified that had homology to nine viral families. The Partitiviridae was the most consistently observed mycoviral family. High variation in the abundance of each detected mycovirus suggests that rumen mycoviral populations vary greatly between individual sheep. Functional analysis of the genes within the assembled mycoviral contigs suggests that the mycoviruses detected had simple genomes, often only carrying the machinery required for replication. The fungal population of the ovine rumen was also assessed using metagenomics data from the same samples, and was consistently dominated by the phyla Ascomycota and Basidomycota. The strictly anaerobic phyla Neocallimastigomycota were also present in all samples but at a low abundance. This preliminary investigation has provided clear evidence that mycoviruses with RNA genomes exist in the rumen, with further in-depth studies now required to characterise this mycoviral community and determine its role in the rumen.