Abstract:________________________________________________________________________________ AbstractSixty high-producing multiparous Holstein cows were used in a randomized complete block design experiment to determine the effect of a direct-fed microbial (DFM), Megasphaera elsdenii NCIMB 41125 (Me), on dairy cattle productivity and health. The cows received one of two experimental diets (total mixed rations (TMR)) from calving until 60 days post partum. Two experimental diets were formulated, namely a low concentrate di… Show more
“…In the study by Wallace et al [44] in beef cattle, although not reported in the paper itself, the abundance of M. elsdenii was 13-fold higher in the low-methane steers, thus entirely consistent with the results of Shabat et al [46]. M. elsdenii has been trialled with some success as a probiotic for ruminants on the grounds of its pH-stabilizing properties [52, 53]. Thus, thanks to these studies, a picture is emerging whereby it can be seen that differences in the abundance of H 2 -producing bacteria, non-H 2 -producing bacteria and H 2 utilisers, together with the abundance of pH-stabilizing bacteria, affect the quantity of methane that a ruminant animal produces and its feed efficiency.Fig.…”
Methane emissions from ruminal fermentation contribute significantly to total anthropological greenhouse gas (GHG) emissions. New meta-omics technologies are beginning to revolutionise our understanding of the rumen microbial community structure, metabolic potential and metabolic activity. Here we explore these developments in relation to GHG emissions. Microbial rumen community analyses based on small subunit ribosomal RNA sequence analysis are not yet predictive of methane emissions from individual animals or treatments. Few metagenomics studies have been directly related to GHG emissions. In these studies, the main genes that differed in abundance between high and low methane emitters included archaeal genes involved in methanogenesis, with others that were not apparently related to methane metabolism. Unlike the taxonomic analysis up to now, the gene sets from metagenomes may have predictive value. Furthermore, metagenomic analysis predicts metabolic function better than only a taxonomic description, because different taxa share genes with the same function. Metatranscriptomics, the study of mRNA transcript abundance, should help to understand the dynamic of microbial activity rather than the gene abundance; to date, only one study has related the expression levels of methanogenic genes to methane emissions, where gene abundance failed to do so. Metaproteomics describes the proteins present in the ecosystem, and is therefore arguably a better indication of microbial metabolism. Both two-dimensional polyacrylamide gel electrophoresis and shotgun peptide sequencing methods have been used for ruminal analysis. In our unpublished studies, both methods showed an abundance of archaeal methanogenic enzymes, but neither was able to discriminate high and low emitters. Metabolomics can take several forms that appear to have predictive value for methane emissions; ruminal metabolites, milk fatty acid profiles, faecal long-chain alcohols and urinary metabolites have all shown promising results. Rumen microbial amino acid metabolism lies at the root of excessive nitrogen emissions from ruminants, yet only indirect inferences for nitrogen emissions can be drawn from meta-omics studies published so far. Annotation of meta-omics data depends on databases that are generally weak in rumen microbial entries. The Hungate 1000 project and Global Rumen Census initiatives are therefore essential to improve the interpretation of sequence/metabolic information.
“…In the study by Wallace et al [44] in beef cattle, although not reported in the paper itself, the abundance of M. elsdenii was 13-fold higher in the low-methane steers, thus entirely consistent with the results of Shabat et al [46]. M. elsdenii has been trialled with some success as a probiotic for ruminants on the grounds of its pH-stabilizing properties [52, 53]. Thus, thanks to these studies, a picture is emerging whereby it can be seen that differences in the abundance of H 2 -producing bacteria, non-H 2 -producing bacteria and H 2 utilisers, together with the abundance of pH-stabilizing bacteria, affect the quantity of methane that a ruminant animal produces and its feed efficiency.Fig.…”
Methane emissions from ruminal fermentation contribute significantly to total anthropological greenhouse gas (GHG) emissions. New meta-omics technologies are beginning to revolutionise our understanding of the rumen microbial community structure, metabolic potential and metabolic activity. Here we explore these developments in relation to GHG emissions. Microbial rumen community analyses based on small subunit ribosomal RNA sequence analysis are not yet predictive of methane emissions from individual animals or treatments. Few metagenomics studies have been directly related to GHG emissions. In these studies, the main genes that differed in abundance between high and low methane emitters included archaeal genes involved in methanogenesis, with others that were not apparently related to methane metabolism. Unlike the taxonomic analysis up to now, the gene sets from metagenomes may have predictive value. Furthermore, metagenomic analysis predicts metabolic function better than only a taxonomic description, because different taxa share genes with the same function. Metatranscriptomics, the study of mRNA transcript abundance, should help to understand the dynamic of microbial activity rather than the gene abundance; to date, only one study has related the expression levels of methanogenic genes to methane emissions, where gene abundance failed to do so. Metaproteomics describes the proteins present in the ecosystem, and is therefore arguably a better indication of microbial metabolism. Both two-dimensional polyacrylamide gel electrophoresis and shotgun peptide sequencing methods have been used for ruminal analysis. In our unpublished studies, both methods showed an abundance of archaeal methanogenic enzymes, but neither was able to discriminate high and low emitters. Metabolomics can take several forms that appear to have predictive value for methane emissions; ruminal metabolites, milk fatty acid profiles, faecal long-chain alcohols and urinary metabolites have all shown promising results. Rumen microbial amino acid metabolism lies at the root of excessive nitrogen emissions from ruminants, yet only indirect inferences for nitrogen emissions can be drawn from meta-omics studies published so far. Annotation of meta-omics data depends on databases that are generally weak in rumen microbial entries. The Hungate 1000 project and Global Rumen Census initiatives are therefore essential to improve the interpretation of sequence/metabolic information.
“…This is in contrast to the results of Aikman et al (2009) who found that milk fat and protein were reduced by Me in high-producing cows on both their standard and high-energy diets. Hagg et al (2010) on the other hand found no significant effect of Me on milk composition. These variable responses in milk composition are probably associated with differences in dietary composition and feed processing: the primary energy source in the present trial was steam-flaked sorghum and maize meal, whereas it was wheat and barley in the trial of Aikman et al (2009) and maize meal only in the trial of Hagg et al (2010).…”
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confidence: 70%
“…Hagg et al (2010) on the other hand found no significant effect of Me on milk composition. These variable responses in milk composition are probably associated with differences in dietary composition and feed processing: the primary energy source in the present trial was steam-flaked sorghum and maize meal, whereas it was wheat and barley in the trial of Aikman et al (2009) and maize meal only in the trial of Hagg et al (2010). It is well-established that these sources differ in ruminal fermentation rate, and consequently in ruminal passage rate (NRC, 2001).…”
The objective of the study was to determine whether early post-partum dosing of Megasphaera elsdenii NCIMB 41125 (Me) will be beneficial to performance of high producing TMR-fed cows. Sixty multiparous Holstein cows were randomly allocated to four treatments (60% or 70% concentrate diet and placebo or Me [single oral dose of 10 11 cfu in 250 mL suspension on day of calving and Days 10 and 20 postpartum, respectively]). Observations were recorded between calving and 80 days post-partum. Performance data were analysed for all 60 cows combined and for the 40 highest producing cows only, since they were considered more susceptible to ruminal acidosis. For all 60 cows, body weight, condition score and milk yield tended to increase with Me, but data for the 40 highest producing cows suggested that this response could be ascribed primarily to higher producing cows on the higher concentrate diet. Dry matter intake and milk protein were not affected by Me, whereas milk fat percentage increased with Me but only in cows on the 60% concentrate diet. Results support the hypothesis that dosing with Megasphaera elsdenii is most likely to benefit higher producing cows with greater risk of acidosis.
“…Several reports have described experiments in which M. elsdenii was deliberately dosed into the rumen to gauge its effects on ruminal chemistry (pH and organic acid concentrations) and animal performance. These studies have yielded contradictory results (Klieve et al, 2003;Hagg et al, 2010;Meissner et al, 2010;Aikman et al, 2011;Henning et al, 2011); in general, treatment effects on both ruminal pH and milk production and composition have been minimal or absent. But in only one of these studies (Klieve et al, 2003) were any population assessments made to determine whether or not the dosed strain persisted in the rumen, which is a key consideration given the well-known difficulty of establishing exogenously added strains in a well-adapted animal (Weimer, 1998).…”
Megasphaera elsdenii is a lactate-utilizing bacterium whose ruminal abundance has been shown to be greatly elevated during milk fat depression (MFD). To further examine this association, a total of 23 cannulated multiparous Holstein cows were examined in 3 experiments in which strains of M. elsdenii were directly dosed into the rumen (~2 × 10(12) cells/dose); control cows were dosed with sterile lactate-free culture medium. Cows were fed a total mixed ration (292 g of starch/kg of dry matter) that contained primarily corn silage, alfalfa silage, finely ground high-moisture corn, supplemental protein, and corn oil (3 g/kg of dry matter). Experiments differed in stage of lactation of the cows (early or late), dosing events (single dose, or 4 doses over a 5-d period), timing of dose (prefeed or 4 h postfeed), and M. elsdenii strain (laboratory strain YI9 or 3 strains isolated from cows in the same herd). Dry matter intake and milk yield and composition were measured from 5 to 0 d before dosing and 1 to 7d after first dosing, plus later time points that varied by experiment. Milk yield and composition were not affected by dosing. Megasphaera elsdenii was quantified in the liquid phase of ruminal contents by automated ribosomal intergenic spacer analysis, or by PCR with relative quantification (M. elsdenii 16S rRNA gene copy number as a percentage of total bacterial 16S rRNA gene copies). Neither the M. elsdenii-dosed or control cows displayed MFD after dosing, and in almost all cases M. elsdenii populations returned to low baseline levels (<0.02% of 16S rRNA gene copy number) within 24 h of dosing. This rapid decline in M. elsdenii also occurred in several cows that were dosed with a strain of M. elsdenii that had been isolated from that particular cow during a previous bout of MFD. Ruminal pH and total millimolar volatile fatty acids and lactate did not differ between dosed and control cows, although acetate-to-propionate ratio declined in both groups and butyrate increased after dosing with M. elsdenii. The results confirm that establishing exogenously added bacterial strains in the rumen is difficult, even for strains previously isolated from the recipient cow. The potential role of M. elsdenii as an agent of MFD remains unclear in the absence of successful establishment of the dosed strains.
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