Diversity Of Rumen Methanogens Research Articles

Weaning methods affect ruminal methanogenic archaea composition and diversity in Holstein calves

The objective of the present study was to examine the effect of different weaning methods on the ruminal methanogenic archaea composition and diversity in Holstein calves. Thirty-six newborn Holstein bull calves were assigned to 1 of 3 treatments: (1) conventional weaning (d 56) and fed a high proportion of solid feed (CWS); (2) conventional weaning (d 56) and fed a high proportion of liquid feed (CWL); (3) early weaning (d 42) and fed with a high proportion of solid feed (EWS). High-throughput sequencing of the methyl coenzyme M reductase (mcrA) gene, which encodes the α-subunit of methyl coenzyme M reductase — the enzyme that catalyzes the final step in methanogenesis was used to determine the composition and diversity of rumen methanogens. No significant difference (P>0.05) was observed for operational taxonomic units (OTUs) or richness indices, but diversity indices increased (P<0.05) for calves fed high dietary solids. Predominant families across the three treatments were Methanobacteriaceae, Thermoplasmataceae and Methanomassiliicoccaceae. Calves in the EWS treatment had a higher (P<0.05) relative abundance of Methanobrevibacter sp. strain AbM4 and Methanosphaera stadtmanae, while calves in the CWL treatment had a higher (P<0.05) abundance of Methanosphaera sp. strain SM9. A positive (P<0.05) relationship was identified between butyrate and Methanobrevibacter sp. strain AbM4. In conclusion, the composition and diversity of methanogens in the rumen of Holstein calves varied under the different weaning methods. This study identified a positive relationship between butyrate and Methanobrevibacter sp. strain AbM4, potentially reflecting correlations between ruminal fermentation variables and methanogenesis function. These in-depth analyses provide further understanding of weaning methods for intensified production systems.

The 16S rRNA and mcrA gene based comparative diversity of methanogens in cattle fed on high fibre based diet

In the present study, the diversity of rumen methanogens in crossbred Karan Fries cattle was determined by constructing 16S rRNA and mcrA (methyl coenzyme-M reductase α subunit) gene libraries using specific primers. All thirteen OTUs or phylotypes from 16S rRNA library clustered with order Methanobacteriales, twelve of which aligned with Methanobrevibacter spp., whereas one OTU resemble with Methanosphaera stadtmanae. Out of eighteen OTUs identified from mcrA gene library, fifteen clustered with order Methanobacteriales, two resemble with Methanomicrobiales and remaining one grouped with Methanosarcinales. These results revealed that Methanobrevibacter phylotype was predominantly present in Karan Fries crossbred cattle fed on high fibrous diet containing wheat straw. Compared to 16S rRNA gene, mcrA gene OTUs clustered in three orders providing better insights of rumen methanogens diversity in cattle.

Effects of Leucaena leaf pellet on bacterial diversity and microbial protein synthesis in swamp buffalo fed on rice straw

The experiment was conducted to determine the effect of Leucaena leaf pellet (LLP) supplementation on feed intake, microbial protein synthesis and rumen microbial population and diversity in swamp buffalo fed on rice straw. Four swamp buffalo bulls were randomly assigned according to a 4×4 Latin square design to receive LLP at 0, 150, 300 and 450g/hd/d. Untreated rice straw was fed ad libitum, while concentrate was fed at 5g/kg BW. The results revealed that rice straw intake and total intake were significantly improved when level of LLP supplementation increased. Ruminal NH3–N concentration was significantly higher than in the control group. Population of fungal zoospores, amylolytic bacteria, proteolytic bacteria and cellulolytic bacteria were significantly increased (P<0.05) with increasing LLP supplementation while the population of rumen protozoa decreased. Supplementation of LLP increased the population of total bacteria, Ruminococcus albus, Fibrobacter succinogenes, and Ruminococcus flavefaciens, while population of methanogenic bacteria were decreased (P<0.05). The N balance and microbial nitrogen supply were remarkably improved when LLP supplementation level increased. Rumen methanogen diversity was not shifted as analyzed by PCR-DGGE technique, while rumen total bacterial diversity was similar by sampling time and treatments. Supplementation of LLP can improved rumen ecology, thus improved N-retention and microbial N supply.

Methyl coenzyme M reductase (mcrA) gene based phylogenetic analysis of methanogens population in Murrah buffaloes (Bubalus bubalis)

The aim of the present study was to decipher the diversity of methanogens in rumen of Murrah buffaloes so that effective strategies can be made in order to mitigate methane emission from these methanogens. In the present study diversity of rumen methanogens in Murrah buffaloes (Bubalus bubalis) from North India was evaluated by using mcr-A gene library obtained from the pooled PCR product from four animals and by using MEGA4 software. A total of 104 clones were examined, revealing 26 different mcr-A gene sequences or phylotypes. Of the 26 phylotypes, 16 (64 of 104 clones) were less than 97% similar to any of the cultured strain of methanogens. Seven clone sequences were clustered with Methanomicrobium mobile and three clone sequences were clustered with Methanobrevibacter gottschalkii during the phylogenetic analysis. Uncultured group of methanogens comes out to be the major component of the methanogens community structure in Murrah buffaloes. Methanomicrobium phylotype comes out to be major phylotype among cultured methanogens followed by Methanobrevibacter phylotype. These results help in making effective strategies to check the growth of dominant communities in the rumen of this animal which in turn help in the reduction of methane emission in the environment and ultimately helps us in fighting with the problem of global warming.

Long-Term Monensin Supplementation Does Not Significantly Affect the Quantity or Diversity of Methanogens in the Rumen of the Lactating Dairy Cow

A long-term monensin supplementation trial involving lactating dairy cattle was conducted to determine the effect of monensin on the quantity and diversity of rumen methanogens in vivo. Fourteen cows were paired on the basis of days in milk and parity and allocated to one of two treatment groups, receiving (i) a control total mixed ration (TMR) or (ii) a TMR with 24 mg of monensin premix/kg of diet dry matter. Rumen fluid was obtained using an ororuminal probe on day -15 (baseline) and days 20, 90, and 180 following treatment. Throughout the 6-month experiment, the quantity of rumen methanogens was not significantly affected by monensin supplementation, as measured by quantitative real-time PCR. The diversity of the rumen methanogen population was investigated using denaturing gradient gel electrophoresis (DGGE) and 16S rRNA clone gene libraries. DGGE analysis at each sampling point indicated that the molecular diversity of rumen methanogens from monensin-treated cattle was not significantly different from that of rumen methanogens from control cattle. 16S rRNA gene libraries were constructed from samples obtained from the rumen fluids of five cows, with a total of 166 clones examined. Eleven unique 16S rRNA sequences or phylotypes were identified, five of which have not been recognized previously. The majority of clones (98.2%) belonged to the genus Methanobrevibacter, with all libraries containing Methanobrevibacter strains M6 and SM9 and a novel phylotype, UG3322.2. Overall, long-term monensin supplementation was not found to significantly alter the quantity or diversity of methanogens in the rumens of lactating dairy cattle in the present study.