Bovine Rumen Research Articles

Climate Cattle

Scientific measurement and prediction tools have highlighted the significant greenhouse gas contributions of farmed animals, particularly dairy and meat cows. Emergent analysis and associated political discourse have refigured narratives of blame for the contemporary climate crisis, influencing international policy and inspiring a range of technological and economic fixes to construct “climate cattle” as keystone species for a “good Anthropocene.” Interventions are centered on bovine metabolisms at different spatial and temporal scales; they include the use of feed supplements that inhibit methane production in bovine rumens during digestion, and selective breeding or genetic engineering for the breeding of future-ready low-methane cows. In these bovine “technofix” solutions, the global scale is invoked to drive metabolic interventions at multiple smaller scales including individual cows, their microbiomes, and their genomes. Research, however, suggests that these interventions do not neatly scale back up as invoked by those deploying them for climate-related ends. Rather, the global scale functions discursively to incentivize bovine metabolic intervention, influence agricultural policies, and draw investment into ecomodernist visions of “good cows for a good Anthropocene.” Through examining how cows figure as both problems and solutions through metabolic interventions, this article traces the importance of, and issues with, scale in contemporary environmental governance.

Growth Performance, Nutrient Digestibility, Carcass Characteristics and Organoleptic Properties of Broiler Chicken Fed Cocoa Bean Shell

The high cost of conventional feed ingredients has forced poultry farmers to concentrate on more accessible and reasonably priced alternative feed sources having considerable nutritional potential. One of these alternative feed sources is cocoa bean shell (CBS), which is widely available, inexpensive, and nutritious. There is limited research on the application of fermentation of bovine rumen filtrate on CBS in poultry production. A feeding trial for 56 days was conducted to investigate the dietary effect of rumen filtrate fermented cocoa bean shell (RFCBS) as partial replacement for maize on the performance of broiler chickens. Fresh cocoa bean shell was mixed with rumen filtrate obtained at ratio 1:1, fermented for 24 hours and then dried. The dried fermented cocoa bean shell (FCBS) was incorporated into the experimental diets at varying levels; 0, 5, 10, 15 and 20% respectively to formulate five experimental diets. Ross 308 broiler chicks (n=150) were randomly allotted into five treatments groups of thirty (30) birds per treatment and three replicates containing ten birds each in a completely randomized design (CRD). Data on performance indices, hematological, nutrient digestibility, carcass characteristics and sensory evaluation collected during the experiment were subjected to ANOVA at α = 0.05. Results revealed that fermentation method employed had significant influence (P<0.05) on the chemical composition of cocoa bean shell used in this study. The crude protein (CBS: 8.18% – FCBS: 5.10%), ash (CBS: 10.40% - FCBS: 9.08%), nitrogen free extract (CBS: 57.64% - FCBS: 57.07%) content of the cocoa bean shell reduced after being fermented but increased its crude fibre content from 10.27% to 15.26%. It also helped to improve the phytochemical constituents of CBS. Dietary supplementation up to 10 % FCBS had comparable weight gain, feed intake and the best feed conversion ratio. Birds fed 10% FCBS based diet had improved (P<0.05) nutrient digestibility values when compared with other diets. Birds on 0 (2088.89g/b), 5 (2044.44g/b) and 10 (1944.44g/b) % FCBS had similar dressed weight but recorded significantly the highest value. Birds fed 10% FCBS based diet recorded the highest tenderness (8.33), juiciness (8.37), flavour (8.43), colour (8.30), aroma (8.37) and taste (8.00) values. Results indicated that the cost of the feed per kg (#2178.92 - 2229.23) decreased across the dietary treatments as the FCBS increased. It is concluded that FCBS can be incorporated up to 10 % in broiler chickens’ diet for better output in terms of weight gain, feed intake, feed conversion ratio, carcass trait sensory evaluation and better health status of the birds.

SENSORY EVALUATION OF MEAT OBTAINED FROM BROILER CHICKENS FED DIETARY BOVINE RUMEN FILTRATE FERMENTED COCOA BEAN SHELL

A sensory evaluation was conducted on meat obtained of broiler chickens fed for 56 days on diet containing graded levels of bovine rumen filtrate Fermented Cocoa Bean Shell (FCBS). Fresh cocoa bean shell was mixed with rumen filtrate obtained at ratio 5:5, fermented and then dried. The dried fermented cocoa bean shell was incorporated into the experimental diets at varying levels; 0, 5, 10, 15 and 20% respectively to formulate five experimental diets. One hundred and fifty one-day old broiler chickens were randomly allotted into five treatment groups with thirty (30) birds per treatment and three replicates containing ten birds each in a completely randomized design. At the end of the feeding trial, after being fasted for 12 h; three birds per replicate were randomly selected and sacrificed; then the sensory evaluation of the cooked samples were carried out by 10 panelists. Parameters; colour, juiciness, flavour, tenderness, aroma and taste were evaluated by the panellist using a nine point hedonic scale. The collected data on sensory traits were analysed using ANOVA at (P<0.05). Tenderness (7.60 – 8.33), juiciness (7.40 – 8.37), flavour (7.37 – 8.43), colour (7.53 - 8.30), aroma (7.53 – 8.37) and taste (7.07 – 8.13) of the cooked meat samples varied significantly across the dietary treatments in which birds fed 10% FCBS based diet recorded the highest values (8.33, 8.37, 8.43, 8.30, 8.37 and 8.00) respectively. Therefore, the meat sample on 10% FCBS based diet recorded highest level of preference across the dietary treatments investigated.

FERTILIZER EFFECTS OF BOVINE RUMEN CONTENT ON PERFORMANCE OF GAMBA GRASS (ANDROPOGON GAYANUS) IN SEMI-ARID REGION, BORNO STATE, NIGERIA

Animal waste in developing countries like Nigeria due to its bulky, low-grade composition and high water content. Research on the use of this waste as a plant nutrient source is limited, but Gamba grass has shown potential as a high-yielding option for utilizing these wastes. Therefore, the objective of the study was to determine the effects of bovine rumen content as fertilizer on growth components, yield and quality of Andropogon gayanus (Gamba Grass) in semi-arid region of Borno state. A Nine plots measuring 3m x 3m each were laid in a completely randomized design (CRD) Three levels (0, 8 and 12t/ha-1) of bovine rumen content were applied into the soil with three replication. Gamba grass tiller crown were transplanted at 50cm x 50cm intra and inter row spacing. The parameters measured were plant heigh, plant width, leaf width, leaf length and number of tillers while a cutting of 10cm from each treatment (replicate) was done at different age after transplanting (4,6 and 8 weeks) and yield harvesting was done at 97 days. The results indicated that bovine rumen content significantly (P<0.05) influenced growth components of A.gayanus. There wass no significant (p>0.05) effect on all growth components at weeks 4 and 10 between the treatment (0, 8, and 12t/ha-1) respectively. However, it was observed that plant height increasde with increase in number of cutting interval with the higher regrowth at 10 WAT with 108.60 at 8ton/ha, and lowest with 96.60 regrowth height at 0ton/ha respectively. Based on the findings of this study, it was suggested that rumen contents at the rate of 12ton/ha is recommended. The study recommended that further studies should be carried out during the raining season to ascertain the potential yield and herbage quality of A. gayanus on different rumen contents rates.

In vitro and ex vivo metabolism of chemically diverse fructans by bovine rumen Bifidobacterium and Lactobacillus species

BackgroundInulin and inulin-derived fructooligosaccharides (FOS) are well-known prebiotics for use in companion animals and livestock. The mechanisms by which FOS contribute to health has not been fully established. Further, the fine chemistry of fructan structures from diverse sources, such as graminan-type fructans found in cereal crops, has not been fully elucidated. New methods to study fructan structure and microbial responses to these complex carbohydrates will be key for evaluating the prebiotic potency of cereal fructans found in cattle feeds. As the rumen microbiome composition is closely associated with their metabolic traits, such as feed utilization and waste production, prebiotics and probiotics represent promising additives to shift the microbial community toward a more productive state.ResultsWithin this study, inulin, levan, and graminan-type fructans from winter wheat, spring wheat, and barley were used to assess the capacity of rumen-derived Bifidobacterium boum, Bifidobacterium merycicum, and Lactobacillus vitulinus to metabolize diverse fructans. Graminan-type fructans were purified and structurally characterized from the stems and kernels of each plant. All three bacterial species grew on FOS, inulin, and cereal crop fructans in pure cultures. L. vitulinus was the only species that could metabolize levan, albeit its growth was delayed. Fluorescently labelled polysaccharides (FLAPS) were used to demonstrate interactions with Gram-positive bacteria and confirm fructan metabolism at the single-cell level; these results were in agreement with the individual growth profiles of each species. The prebiotic potential of inulin was further investigated within naïve rumen microbial communities, where increased relative abundance of Bifidobacterium and Lactobacillus species occurred in a dose-dependent and temporal-related manner. This was supported by in situ analysis of rumen microbiota from cattle fed inulin. FLAPS probe derived from inulin and fluorescent in situ hybridization using taxon-specific probes confirmed that inulin interacts with Bifidobacteria and Lactobacilli at the single-cell level.ConclusionThis research revealed that rumen-derived Bifidobacteria and Lactobacilli vary in their metabolism of structurally diverse fructans, and that inulin has limited prebiotic potential in the rumen. This knowledge establishes new methods for evaluating the prebiotic potential of fructans from diverse plant sources as prebiotic candidates for use in ruminants and other animals.

Integrating genome-and transcriptome-wide association studies to uncover the host-microbiome interactions in bovine rumen methanogenesis.

The ruminal microbiota generates biogenic methane in ruminants. However, the role of host genetics in modifying ruminal microbiota-mediated methane emissions remains mysterious, which has severely hindered the emission control of this notorious greenhouse gas. Here, we uncover the host genetic basis of rumen microorganisms by genome-and transcriptome-wide association studies with matched genome, rumen transcriptome, and microbiome data from a cohort of 574 Holstein cattle. Heritability estimation revealed that approximately 70% of microbial taxa had significant heritability, but only 43 genetic variants with significant association with 22 microbial taxa were identified through a genome-wide association study (GWAS). In contrast, the transcriptome-wide association study (TWAS) of rumen microbiota detected 28,260 significant gene-microbe associations, involving 210 taxa and 4652 unique genes. On average, host genetic factors explained approximately 28% of the microbial abundance variance, while rumen gene expression explained 43%. In addition, we highlighted that TWAS exhibits a strong advantage in detecting gene expression and phenotypic trait associations in direct effector organs. For methanogenic archaea, only one significant signal was detected by GWAS, whereas the TWAS obtained 1703 significant associated host genes. By combining multiple correlation analyses based on these host TWAS genes, rumen microbiota, and volatile fatty acids, we observed that substrate hydrogen metabolism is an essential factor linking host-microbe interactions in methanogenesis. Overall, these findings provide valuable guidelines for mitigating methane emissions through genetic regulation and microbial management strategies in ruminants.

Cellulolytic characterization of the rumen-isolated Acinetobacter pittii ROBY and design of a potential controlled-release drug delivery system

A novel cellulolytic bacterial strain, ROBY, was isolated from a bovine rumen sample using the enrichment culture method. This isolate was found to be Acinetobacter pittii, with >99 % similarity according to 16S rRNA gene sequence analysis. The potential use of this strain in combination with doxorubicin (Dox)-integrated cellulose nanoparticles (Dox-CNPs) was evaluated as a proof-of-concept study for the further development of this approach as a novel controlled-release drug delivery strategy. The isolate can utilize CNPs as the sole carbon source for growth and degrade both Dox-CNPs and empty CNPs with high efficiency. Extracellular cellulases isolated from bacteria may also be used to trigger Dox release. The results also demonstrated that the release of Dox into the environment due to nanoparticle degradation in the samples incubated with Dox-CNPs significantly affected bacterial cell viability (∼75 % decrease), proving the release of Dox due to bacterial cellulase activity and suggesting the great potential of this approach for further development.

GROWTH PERFORMANCE OF CROSSBRED WEANER RABBITS FED DEHYDRATED BOVINE RUMEN DIGESTA

Twenty four crossbred rabbit of mixed sexes were used to evaluate the effect of different inclusion levels of dehydrated bovine rumen digesta (DBRD) on growth performance, carcass and organ characteristics of weaner rabbits. Four diets were formulated to contain 0% (control), 5, 10 and 15% DBRD. The rabbits were randomly divided into four groups and allotted into four treatments of 6 rabbits each in a completely randomized design (CRD). The trial lasted for 8 weeks. The result showed that the final body weight, average daily weight gain and feed conversion ratio values of rabbits on 5, 10 and 15% DBRD diets were comparable (p>0.05) to those of rabbits on the control diet. The average daily feed intake was significantly (p<0.05) increased as the levels of the test material increased. Nutrient intake by the rabbits were significantly (p<0.05) increased with the increase in DBRD inclusion levels. Apparent nutrient digestibility was affected (p<0.05) significantly by the diets. It was concluded that up to 15% of graded levels of DBRD can be included in the diet of weaner rabbits without any deleterious effect on performance.

Biochemical characterization of a SusD-like protein involved in β-1,3-glucan utilization by an uncultured cow rumen Bacteroides.

In ruminants, the rumen is a specialized stomach that is adapted to the breakdown of plant-derived complex polysaccharides through the coordinated activities of a diverse microbial community. Bacteroidota is a major phylum in this bovine rumen microbiota. They contain several clusters of genes called polysaccharide utilization loci (PULs) that encode proteins working in concert to capture, degrade, and transport polysaccharides. Despite the critical role of SusD-like proteins for efficient substrate transport, they remain largely unexplored. Here, we present the biochemical characterization of a SusD-like protein encoded by a β-glucan utilization locus from an Escherichia coli metagenomic clone previously isolated by functional screening of the bovine rumen microbiome. In this study, we show that clone 41O1 can grow on laminaritriose, cellotriose, and a mixture of cellobiosyl-cellobiose and glucosyl-cellotriose as sole carbon sources. Based on this, we used various in vitro analyses to investigate the binding ability of 41O1_SusD-like towards these oligosaccharides and the corresponding polysaccharides. We observed a clear binding affinity for β-1,6 branched β-1,3-glucans (laminarins, yeast β-glucan) and laminaritriose. Comparison of the AlphaFold2 model of 41O1_SusD-like with its closest structural homologs highlights a similar pattern of substrate recognition. In particular, three tryptophan residues are shown to be crucial for laminarin recognition. In the context of the cow rumen, we discuss the possible substrates targeted by the 41O1_PUL, such as the (1,3;1,4)-β-d-glucans present in cereal grains or the β-1,3- and (1,3;1,6)-β-d-glucans that are components of the cell wall of ruminal yeasts.IMPORTANCEThe rumen microbiota can majorly impact overall animal health, feed efficiency, and release of harmful substances into the environment. This microbiota is involved in the fermentation of organic matter to provide the host with valuable and assimilable nutrients. Bacteroidota efficiently captures, breaks down, and imports complex polysaccharides through the concerted action of proteins encoded by polysaccharide utilization loci (PULs). Within this system, SusD-like protein has proven necessary for the active internalization of the substrate. Nevertheless, the vast majority of SusD-like proteins characterized to date originate from cultured bacteria. With regard to the diversity and importance of uncultured bacteria in the rumen, further studies are required to better understand the role of polysaccharide utilization loci in ruminal polysaccharide degradation. Our detailed characterization of the 41O1_SusD-like therefore contributes to a better understanding of the carbohydrate metabolism of an uncultured Bacteroides from the cow rumen.

Characterization of BrGH3A, a bovine rumen-derived glycoside hydrolase family 3 β-glucosidase with a permuted domain arrangement.

The bovine rumen contains a large consortium of residential microbes that release a variety of digestive enzymes for feed degradation. However, the utilization of these microbial enzymes is still limited because these rumen microorganisms are mostly anaerobes and are thus unculturable. Therefore, we applied a sequence-based metagenomic approach to identify a novel 2,445-bp glycoside hydrolase family 3 β-glucosidase gene known as BrGH3A from the metagenome of bovine ruminal fluid. BrGH3A β-glucosidase is a 92-kDa polypeptide composed of 814 amino acid residues. Unlike most glycoside hydrolases in the same family, BrGH3A exhibited a permuted domain arrangement consisting of an (α/β)6 sandwich domain, a fibronectin type III domain and a (β/α)8 barrel domain. BrGH3A exhibited greater catalytic efficiency toward laminaribiose than cellobiose. We proposed that BrGH3A is an exo-acting β-glucosidase from Spirochaetales bacteria that is possibly involved in the intracellular degradation of β-1,3-/1,4-mixed linkage glucans that are present in grass cell walls. BrGH3A exhibits rich diversity in rumen hydrolytic enzymes and may represent a member of a new clan with a permuted domain topology within the large family.

Microbiome-informed study of the mechanistic basis of methane inhibition by Asparagopsis taxiformis in dairy cattle.

Livestock emits copious quantities of methane, a major constituent of the greenhouse gases currently driving climate change. Methanogens within the bovine rumen produce methane during the breakdown of feed. While the red seaweed Asparagopsis taxiformis (AT) can significantly reduce methane emissions when fed to cows, its effects appear short-lived. This study revealed that the effective reduction of methane emissions by AT was accompanied by the near-total elimination of methane-generating Methanosphaera. However, Methanosphaera populations subsequently rebounded due to their ability to inactivate bromoform, a major inhibitor of methane formation found in AT. This study presents novel findings on the contribution of Methanosphaera to ruminal methanogenesis, the mode of action of AT, and the possibility for complementing different strategies to effectively curb methane emissions.

Anaerobic co‑digestion of bovine ruminal waste and brewery spent grain: Effects of inoculum to substrate ratio, mixing ratio, process stability, organic matter removal, and methane yield

The technological potential of co-digesting bovine rumen waste (BRW) with brewery spent grain (BSG) is significant, offering enhanced biogas production and effective waste management. This study's findings demonstrate that the anaerobic digestion process becomes significantly more efficient when difficult to degrade BRW is combined with easily degradable BSG. The highest methane yield obtained in the mono-digestion of BRW was 127.11 NmLCH4 gVS−1 with biodegradability of 33.89 % in inoculum to substrate ratio (ISR) 2, and for de BSG obtained was 304.18 NmLCH4 gVS−1 with biodegradability of 68.26 % in ISR 4. The overall average obtained in co-digestion for volatile solids (VS) removal was 26.28 %, and the concentration of methane present in the biogas was 57.18 %. The VS removal efficiency and the increase in biogas and methane yield were directly proportional to the rise in ISR and the proportion of BSG in the mixture. Specifically, the ideal mix of 25 % BRW with 75 % BSG at ISR 4 resulted in a notable methane yield of 255.30 NmLCH4 gVS−1. This process stabilizes digestion and significantly improves solids removal and methane concentration, making it a highly efficient solution for sustainable energy production and industrial waste management.

39 Effects of feeding sun-dried bovine rumen contents on growth and carcass quality of New Zealand White rabbits

This research study aimed to investigate the impact of sun-dried bovine rumen contents (SDBRC) on the growth and linear body measurements of New Zealand White rabbits. The experimental rabbits (n=12) were selected from four New Zealand White bucks and subsequently allocated into three distinct treatments, each with specific dietary compositions. The control group was provided with a standard diet of rabbit pellets, while the experimental groups received rabbit pellets supplemented with 30% (Treatment A) and 40% (Treatment B) of SDBRC. All animals were subjected to consistent and meticulous livestock management practices throughout the 12-week experimental period. There were no significant differences in the growth of rabbits given rabbit pellets and 30% SDBRC. However, the live weight gain and final weights of rabbits on 40% SDBRC inclusion were significantly lower than the 30% SDBRC inclusion and the control (P<0.05). Parameters, such as total feed intake, feed conversion ratio, and dressing percentage were not significantly different (P>0.05). The linear body measurements (heart girth, body length, and abdominal circumference), were not significantly (P>0.05) influenced by dietary variations. Carcass weight for the rabbits on 40% SDBRC inclusion was significantly lower than for rabbits on the control and 30% SBDRC inclusion diets (p=0.001). Other carcass parameters such as meat colour and pH exhibited no significant differences across all three treatments (p>0.05). These findings highlight the promising potential of incorporating SDBRC into rabbit diets, particularly up to 30%, without compromising growth performance and carcass characteristic.

The morphophysiological and yield characteristics of biquinho amarelo pepper in response to bovine rumen residue and chicken litter in soil are dose dependent

In response to the growing demand for environmentally sustainable agricultural practices that enhance production efficiency, this study aimed to determine the optimal application rates of bovine rumen content (CBR) and chicken litter (CCL) as organic composts. Conducted in a controlled greenhouse environment, the research assessed the effects of various doses of these composts on soil chemical and microbiological properties and on the growth and productivity of yellow biquinho pepper (Capsicum chinense Jacq.). The results of this study confirm that organic composts improve soil health and increase the growth and productivity of yellow biquinho pepper. However, while CBR consistently enhances plant growth across a range of doses, CCL shows a dose-dependent response, with the highest fruit production achieved at an application rate of 73.92 Mg ha−1. Although this dose of CCL is beneficial for increasing yield, it also marks a threshold beyond which further increases may lead to negative effects such as nutrient saturation or salt accumulation, potentially resulting in soil toxicity. The study supports the use of CBR and CCL as effective soil conditioners and emphasizes the need to identify the optimal compost dose to efficiently harness the benefits of organic composts in sustainable agricultural practices.

Effect of feeding spent coffee grounds on the methane production in bovine rumen

The environmental impact of methane, a greenhouse gas emitted from ruminants, is a pressing issue and methods to control methane emissions from ruminants are being investigated worldwide. In this study, we investigated the effects of the administration of spent coffee grounds (SCG) on methane production in the rumen in two cows. In the control condition (days 1 and 2), the cows were fed a basic diet twice daily (roughage and concentrate), and in the SCG condition (days 1 and 2) sequentially, the cows were fed the same basic diet and administered SCG into the rumen twice daily. The methane and carbon dioxide concentrations in rumen gas were measured via a fistula after feeding on days 2 in both cases of the study. The measurements were made using a newly developed gas measurement system with a portable gas monitor, and data were obtained for the control condition and SCG condition at each measurement time. The methane ratio at each measurement time was calculated from the methane and carbon dioxide concentrations, and compared between the two conditions. Statistical analysis showed no significant difference between the two conditions in the methane ratios after the morning (P=0.108) and afternoon feedings (P=0.345). However, the methane ratios before the morning (P=0.043) and afternoon feedings (P=0.008) were significantly lower in the SCG condition than in the control condition, suggesting that the administration of SCG may suppress methane production in the rumen.

Production of Hydrogen with Ruminal Microbiota: Finding Culture Conditions for High Yields

Hydrogen is ideal for replacing fossil fuels because upon combustion it generates only water. Dark fermentation (DF) from lignocellulose might be a competitive process for hydrogen production at the industrial scale. However, lignocellulose must be pretreated to obtain fermentable sugars, which is costly and creates pollution. Microorganisms from bovine rumen efficiently degrade lignocellulose. Unfortunately, they have scarcely been explored for the production of hydrogen. Therefore, deeper studies on the culture conditions have to be undertaken to understand the behavior of microbial consortia from the rumen of bovines (MCRB) during hydrogen production. In this work, we evaluated the production of hydrogen by DF with MCRB by varying the incubation time, two culture media (MB and Rhodospirillaceae), headspace (40 and 80 mL), and thermal treatment. It was found that the production of hydrogen was maximum at 16 h MCRB incubation in MB. An amount of 80 mL headspace resulted in a threefold production of hydrogen as compared to 40 mL; the MCRB without heat treatment had a higher H2 yield. The production of hydrogen with 32 MCRB was highly variable, ranging between 21 and 696 mL. Our findings show a different perspective on the treatment of MCRB for the production of hydrogen and give insights on the impact of the culture conditions for increasing hydrogen production.

226 Oral and rumen microbiome characterization to predict host phenotypes

Abstract Studies have utilized rumen microbiome composition and function to predict animal phenotypes. Yet, sample collection for rumen microbial community analysis can be difficult and invasive and hinders the possibility of sampling large animal populations. In this study, we investigated the development of the bovine rumen microbiome over time, to identify the potential of the oral microbiome as a proxy for the rumen microbiome, and to test the applicability of using the oral microbiome for predicting phenotypes in beef cattle. We employed 16S rRNA amplicon sequencing to characterize the rumen and oral bacterial community structure over time and collected both birth and weaning weights in a population of 220 animals. Our findings show that both the oral and rumen microbiomes are established early, and a significant portion of the taxa persists even after weaning. We identified a group of core successional species shared between the oral and rumen bacterial communities, which are established early and persist over time. The oral bacterial community was dominated by phyla Proteobacteria, Firmicutes, Bacteroidota, and Actinobacteria, while the rumen bacterial community was dominated by phyla Bacteroidota, Firmicutes, Verrucomicrobia, Fibrobacteria, and Spirochaetota. Furthermore, we observed that 38% of Amplicon Sequence Variants (ASVs) were shared between the oral and rumen microbiomes at 50 to 120 d of age. At 170 to 240 d of age, 37% of ASVs were shared, and at 295 to 365 d, 33% of ASVs were shared. Finally, at 400 to 468 d, 21% of ASVs were shared. Based on weighted Unifrac analysis, notable differences and distinct clustering was observed between oral and rumen microbiome communities at different sampling ages (P = 0.001; R2 = 0.50969, 50 to 120; P = 0.001; R2 = 0.66247, 170 to 240; P = 0.001; R2 = 0.62036, 295 to 365; and P = 0.001, R2 = 0.66559, 400 to 468). Microbiability estimates varied across different stages and microbial environments. For the oral bacterial community at 50 to 120, the estimates were 0.029%, 0.032%, 0.029%, and 0.028% for birth weight, weaning weight, intramuscular fat (IMF), and ribeye area (REA), respectively. In contrast, the rumen microbiome exhibited microbiability values of 0.034%, 0.058, 0.059, and 0.069% for birth weight, weaning weight, IMF, and REA respectively during the same period. As the animal aged the microbiability increased. At 170 to 240, oral microbiomes showed microbiability estimates of 0.051%, 0.060%, 0.069%, and 0.21% for birth weight, weaning weight, IMF, and REA respectively. In comparison, the rumen microbiome displayed greater microbiability estimates of 0.12%, 0.124%, 0.20%, and 0.26% for birth weight, weaning weight, IMF, and REA respectively. In conclusion, the oral microbiome is not a good proxy for the rumen microbiome composition; however, there is potential to use the oral microbiome for phenotype prediction.

Short communication: Metabolic synthesis of vitamin D2 by the gut microbiome

The origin of vitamin D2 in herbivorous animals was investigated in vivo in sheep and in bovine as well as mouse gastrointestinal tracts. A high concentration of 25-hydroxyvitamin D2 in blood plasma of sheep both in summer and winter appeared to be incompatible with the undetectable level of vitamin D2 in the pasture on which the sheep were grazing. Studies with bovine rumen contents from a cow grazing the same pasture as the sheep, demonstrated an increased concentration of vitamin D2 on anaerobic incubation in a ‘Rusitec’ artificial rumen, which was further enhanced when cellulose powder was added as a fermentation substrate. The colon contents of mice that were fed from weaning on a vitamin D-free diet were found to contain vitamin D2. The results of these comparative studies in 3 animal species indicated that vitamin D2 was being generated by microbial anaerobic metabolism in the gastrointestinal tract.

Yeasts isolated from bovine rumen selected to degrade lignocellulosic roughage

Abstract. Duarte ER, Lima SM, Nere JC, Freitas CES, Maia HAR, Júlio ADL, Abrão FO, Alves JMS, Santos VLD, Geraseev LC, Cota J. 2024. Yeasts isolated from bovine rumen selected to degrade lignocellulosic roughage. Biodiversitas 25: 1159-1166. Commercial yeast strains are viable alternatives to chemical additives in ruminants; however, they are not self to the rumen ecosystem. The present study was conducted to compare the degradation of Urochloa decumbens (Stapf) R.D.Webster (UD) hay and sugarcane bagasse (SB) by eight selected yeast strains, naturally present in the rumen cows and control without microorganisms. Eight yeast isolates that showed >6 log CFU per mL of ruminal fluid were selected and identified as four Pichia kudriavzevii isolates, three Rhodotorula mucilaginosa isolates and one Candida tropicalis isolate, according to their morphological and physiological characteristics and by analyses of the D1 - D2 variable domain sequences of the 28S rRNA gene. The strain V5 (R. mucilaginosa) showed higher cell biomass production than other strains of this species in fermentations with UD (P<0.05). Two isolates of Pichia kudriavzevii (V10 and V62) and one of R. mucilaginosa (V5) promoted a higher reduction of dry matter (DM) of UD than other yeast. The strain V5 was also the most efficient to reduce DM of SB (P <0.05). These selected yeasts could represent a potential alternative for use in animal diets and for industrial applications.

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.